ArticleLiterature Review

Rupnik M, Wilcox MH, Gerding DN.. Clostridium difficile infection: new developments in epidemiology and pathogenesis. Nat Rev Microbiol 7: 526-536

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  • National laboratory for Health, Environment and Food, NLZOH
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Abstract

Clostridium difficile is now considered to be one of the most important causes of health care-associated infections. C. difficile infections are also emerging in the community and in animals used for food, and are no longer viewed simply as unpleasant complications that follow antibiotic therapy. Since 2001, the prevalence and severity of C. difficile infection has increased significantly, which has led to increased research interest and the discovery of new virulence factors, and has expanded and focused the development of new treatment and prevention regimens. This Review summarizes the recent epidemiological changes in C. difficile infection, our current knowledge of C. difficile virulence factors and the clinical outcomes of C. difficile infection.

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... Clostridioides difficile is a highly infectious, Gram-positive, sporeforming anaerobe (Bartlett, 2010) that is recognised as the leading cause of antibiotic-associated diarrhoea, attributing 15-25% of all cases (Ananthakrishnan, 2011). C. difficile infection (CDI) causes a spectrum of intestinal disease, with symptoms ranging from mild diarrhoea to severe pseudomembranous colitis (PMC), bowel perforation and toxic megacolon, which can ultimately be fatal (Rupnik et al., 2009). ...
... In recent years, the incidence of CDI has rapidly increased, and the disease is becoming associated with higher rates of morbidity and mortality (Rupnik et al., 2009;Freeman et al., 2010). A number of hypervirulent C. difficile variants have also emerged, of most note, the BI/NAP1/027 hypervirulent strain (Rupnik et al., 2009;O'Connor et al., 2009), shown to secrete elevated levels of both TcdA and TcdB (Loo et al., 2005;McDonald et al., 2005). ...
... In recent years, the incidence of CDI has rapidly increased, and the disease is becoming associated with higher rates of morbidity and mortality (Rupnik et al., 2009;Freeman et al., 2010). A number of hypervirulent C. difficile variants have also emerged, of most note, the BI/NAP1/027 hypervirulent strain (Rupnik et al., 2009;O'Connor et al., 2009), shown to secrete elevated levels of both TcdA and TcdB (Loo et al., 2005;McDonald et al., 2005). In addition, there has been considerable increase in recurrence and relapse rates associated with CDI (Kelly, 2012), due to the ability to produce endospores . ...
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Clostridioides difficile infection (CDI) is a leading cause of antibiotic-associated diarrhoea. Adhesion of this Gram-positive pathogen to the intestinal epithelium is a crucial step in CDI, with recurrence and relapse of disease dependent on epithelial interaction of its endospores. Close proximity, or adhesion of, hypervirulent strains to the intestinal mucosa are also likely to be necessary for the release of C. difficile toxins, which when internalized, result in intestinal epithelial cell rounding, damage, inflammation, loss of barrier function and diarrhoea. Interrupting these C. difficile -epithelium interactions could therefore represent a promising therapeutic strategy to prevent and treat CDI. Intake of dietary fibre is widely recognised as being beneficial for intestinal health, and we have previously shown that soluble non-starch polysaccharides (NSP) from plantain banana ( Musa spp.), can block epithelial adhesion and invasion of a number of gut pathogens, such as E. coli and Salmonellae. Here, we assessed the action of plantain NSP, and a range of alternative soluble plant fibres, for inhibitory action on epithelial interactions of C. difficile clinical isolates, purified endospore preparations and toxins. We found that plantain NSP possessed ability to disrupt epithelial adhesion of C. difficile vegetative cells and spores, with inhibitory activity against C. difficile found within the acidic (pectin-rich) polysaccharide component, through interaction with the intestinal epithelium. Similar activity was found with NSP purified from broccoli and leek, although seen to be less potent than NSP from plantain. Whilst plantain NSP could not block the interaction and intracellular action of purified C. difficile toxins, it significantly diminished the epithelial impact of C. difficile , reducing both bacteria and toxin induced inflammation, activation of caspase 3/7 and cytotoxicity in human intestinal cell-line and murine intestinal organoid cultures. Dietary supplementation with soluble NSP from plantain may therefore confer a protective effect in CDI patients by preventing adhesion of C. difficile to the mucosa, i.e. a “contrabiotic” effect, and diminishing its epithelial impact. This suggests that plantain soluble dietary fibre may be a therapeutically effective nutritional product for use in the prevention or treatment of CDI and antibiotic-associated diarrhoea.
... It decreases the diversity of commensal bacteria, which compromises resistance to colonization by incoming invading pathogenic bacteria or by existing pathobiont expansion (Modi et al., 2014). The loss of commensal-mediated colonization resistance against pathogens by antibiotics increases the individual susceptibility to enteric pathogen infections such as by S. Typhimurium and EHEC and most notably leads to substantial growth in the abundance of C. difficile, followed by a severe intestinal inflammation (Rupnik et al., 2009;Ayres et al., 2012;Modi et al., 2014;Grünewald and Ruf, 2016;Mullineaux-Sanders et al., 2018). S. Typhimurium, EHEC, and C. difficile are typically the pathogenic bacterial species used for most mechanistic studies investigating such interactions (Modi et al., 2014;Grünewald and Ruf, 2016). ...
... S. Typhimurium, EHEC, and C. difficile are typically the pathogenic bacterial species used for most mechanistic studies investigating such interactions (Modi et al., 2014;Grünewald and Ruf, 2016). C. difficile is a leading nosocomial infectious disease associated with diarrhea and colitis (Rupnik et al., 2009). Typically in the intestine of a healthy human, C. difficile growth is suppressed by commensals, thus controlling its presence and number; however, a substantial increase was seen after treatment with broadspectrum antibiotics in hospitalized patients, followed by an acute intestinal inflammation (Ferreyra et al., 2014b;Rupnik et al., 2009;Grünewald and Ruf, 2016). ...
... C. difficile is a leading nosocomial infectious disease associated with diarrhea and colitis (Rupnik et al., 2009). Typically in the intestine of a healthy human, C. difficile growth is suppressed by commensals, thus controlling its presence and number; however, a substantial increase was seen after treatment with broadspectrum antibiotics in hospitalized patients, followed by an acute intestinal inflammation (Ferreyra et al., 2014b;Rupnik et al., 2009;Grünewald and Ruf, 2016). Like in human, the mouse C. difficile infection model has also reported that C. difficile could not colonize and induce intestinal inflammation in wild-type mice, whereas antibiotic therapy enhanced the incidence of C. difficile infection, which did not disseminate systemically but caused gross damage to the intestinal epithelial barrier via production of their associated toxins TcdA and TcdB (Rupnik et al., 2009;Ng et al., 2010). ...
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The mammalian gut microbial community, known as the gut microbiota, comprises trillions of bacteria, which co-evolved with the host and has an important role in a variety of host functions that include nutrient acquisition, metabolism, and immunity development, and more importantly, it plays a critical role in the protection of the host from enteric infections associated with exogenous pathogens or indigenous pathobiont outgrowth that may result from healthy gut microbial community disruption. Microbiota evolves complex mechanisms to restrain pathogen growth, which included nutrient competition, competitive metabolic interactions, niche exclusion, and induction of host immune response, which are collectively termed colonization resistance. On the other hand, pathogens have also developed counterstrategies to expand their population and enhance their virulence to cope with the gut microbiota colonization resistance and cause infection. This review summarizes the available literature on the complex relationship occurring between the intestinal microbiota and enteric pathogens, describing how the gut microbiota can mediate colonization resistance against bacterial enteric infections and how bacterial enteropathogens can overcome this resistance as well as how the understanding of this complex interaction can inform future therapies against infectious diseases.
... C lostridioides difficile infection (CDI) is estimated to annually cause approximately 500,000 cases per year, with 15,000 to 20,000 attributable deaths in the Unites States alone. 1 The Centers for Disease Control and Prevention (CDC) defines CDI as a positive C difficile toxin assay or a positive C difficile molecular assay (eg, polymerase chain reaction [PCR]) of a stool specimen from a patient of the surveillance catchment area who is 1 year of age or older. 2,3 Cases are further stratified into 2 major epidemiological categories: community-onset CDI, indicating a positive stool specimen collected in an outpatient setting or within 3 calendar days from a patient with no documented overnight stay in a health care facility during the 12 weeks previously; and health care facilityeonset (HCFO) CDI, indicating a positive stool specimen collected more than 3 calendar days after admission to a health care facility. ...
... 7 Health care facilityeonset CDI was defined as a positive stool specimen collected more than 3 calendar days after hospital admission per CDC surveillance definition. 2,3 Measure Our QI initiative measured the incidence of C difficile orders that met testing criteria and were processed (criteria met and tested), C difficile orders discontinued because of not meeting testing criteria (criteria not met and stopped), C difficile orders that did not meet testing criteria and were still processed (criteria not met and tested), and HCFO CDI identified by appropriate and inappropriate testing. An assessment of provider knowledge regarding CDI and diagnostic stewardship preand postintervention was also done. ...
Article
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Objective To reduce health care facility–onset (HCFO) Clostridioides difficile infection (CDI) incidence by improving diagnostic stewardship and reducing the inappropriate testing of C difficile assays. Patients and Methods A multidisciplinary team conducted a quality improvement initiative from January 1, 2020, through March 31, 2021. Clostridioides difficile infection and inappropriate testing were identified via electronic health records using predefined criteria related to stool quantity/caliber, confounding medications, and laboratory data. An intervention bundle was designed including (1) provider education, (2) implementation of an appropriate testing algorithm, (3) expert review of C difficile orders, and (4) batch testing of assays to facilitate review and cancellation if inappropriate. Results Compared with a baseline period from January to September 2020, implementation of our intervention bundle from December 2020 to March 2021 resulted in an 83.6% reduction in inappropriate orders tested and a 41.7% reduction in HCFO CDI incidence. Conclusion A novel prevention bundle improved C difficile diagnostic stewardship and HCFO CDI incidence by reducing testing of inappropriate orders. Such initiatives targeting HCFO CDI may positively affect patient safety and hospital reimbursement.
... Clostridioides difficile is the leading cause of nosocomial diarrhoea in industrialized countries and the aetiological agent of antibiotic-associated pseudomembranous colitis [1][2][3]. The clinical spectrum of C. difficile infection (CDI) ranges from mild, self-limiting diarrhoea to severe outcomes such as fulminant colitis, toxic megacolon, bowel perforation, and sepsis [3,4]. ...
... Clostridioides difficile is the leading cause of nosocomial diarrhoea in industrialized countries and the aetiological agent of antibiotic-associated pseudomembranous colitis [1][2][3]. The clinical spectrum of C. difficile infection (CDI) ranges from mild, self-limiting diarrhoea to severe outcomes such as fulminant colitis, toxic megacolon, bowel perforation, and sepsis [3,4]. ...
Article
Full-text available
The epidemiology of Clostridioides difficile infection (CDI) has changed over the last two decades, due to the emergence of C. difficile strains with clinical relevance and responsible for nosocomial outbreaks with severe outcomes. This study reports an outbreak occurred in a Long-term Care Unit from February to March 2022 and tracked by using a Matrix-Assisted Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) typing approach (T-MALDI); subsequently, a characterization of the toxigenic and antimicrobial susceptibility profiles of the C. difficile isolates was performed. A total of 143 faecal samples belonging to 112 patients was evaluated and C. difficile DNA was detected in 51 samples (46 patients). Twenty-nine C. difficile isolates were obtained, and three different clusters were revealed by T-MALDI. The most representative cluster accounted 22 strains and was considered to be epidemic, in agreement with PCR-Ribotyping. Such epidemic strains were susceptible to vancomycin (MIC ≤ 0.5 mg/mL) and metronidazole (MIC ≤ 1 mg/mL), but not to moxifloxacin (MIC > 32 mg/mL). Moreover, they produced only the Toxin A and, additionally, the binary toxin. To our knowledge, this is the first reported outbreak referable to a tcdA+/tcdB-/cdt+ genotypic profile. In light of these results, T-MALDI is a valid and rapid approach for discovering and tracking outbreaks.
... The symptoms of C. difficile infection (CDI) range from relatively mild diarrhea to severe life-threatening pseudomembranous colitis, toxic megacolon with bowel perforation and a concomitant sepsis (Lessa et al., 2015). In the last two decades, an emerging number of nosocomial and community-acquired infections was reported worldwide (Bartlett, 2006;Rupnik et al., 2009;Lessa et al., 2015). CDI is commonly, but not necessarily associated with previous administration of antibiotics. ...
... Further risk factors are age, cancer treatment and immunosuppression. However, CDI also affects individuals without these classical risk factors (Bignardi, 1998;Rupnik et al., 2009). ...
... sodium hypochlorite (applied at 60°C for 10 min) are recommended for a sporicidal I&I laundry process [19]. According to Rupnik and colleagues (2009), bacterial spores are able to survive typical I&I laundry cycles and a transfer of spores to other laundry items is possible [20]. It was further suggested by Diab-Elschahawi and colleagues (2010), that bleach concentrations usually applied in I&I laundry processes, act not sufficiently sporicidal [21]. ...
... It can lead to a transfer of C. difficile spores to other laundry items and pose a potential health risk for other patients and the health care personnel. Furthermore, the use of subletal concentrations of certain disinfectants can induce sporulation rate and thus increase pathogenicity of C. difficile [20]. The reference household detergent IEC-A* was of very low sporicidal efficiency. ...
Article
Clostridioides difficile associated infections (CDI) develop frequently in hospitalized, elderly patients after an antibiotic treatment. The infection is highly contagious and can be transmitted to other patients when cleaning and disinfection measures are insufficient. Textiles like bed linens or health care personnel uniforms can be involved in the spread of CDI. Spore-forming bacteria are difficult to inactivate and laundering processes efficient against pathogens like Escherichia coli or Staphylococcus aureus, may be insufficient for C. difficile spores. In the present study, the sporicidal effect of laundering processes was investigated systematically. Simulated washing tests were performed with biomonitors containing Bacillus subtilis spores. B. subtilis is a suitable model strain for C. difficile with comparable tolerance against disinfectants, heat and extreme pH values. The efficiency of different Peracetic acid (PAA) and sodium hypochlorite concentrations against B. subtilis spores was tested at different temperatures and contact times. Furthermore, a bleach-containing household detergent was included in the investigation. PAA concentrations, typically applied in I&I laundry cycles, were able to reduce B. subtilis spores sufficiently. Less effective were the tested NaClO-concentrations. The household laundry detergent failed to remove a significant number of bacterial spores.
... The symptoms of C. difficile infection (CDI) range from relatively mild diarrhea to severe life-threatening pseudomembranous colitis, toxic megacolon and a subsequent sepsis (Lessa et al., 2015). In the last two decades, an emerging number of nosocomial and community-acquired infections was reported worldwide (Bartlett, 2006;Rupnik et al., 2009;Lessa et al., 2015). CDI is commonly, but not necessarily associated with previous administration of antibiotics. ...
... Further risk factors are age, cancer treatment and immunosuppression. However, CDI also affects individuals without these classical risk factors (Bignardi, 1998;Rupnik et al., 2009). ...
... Many factors influence toxin production and a great number of regulators have been identified so far, but these have been reviewed elsewhere (Martin-Verstraete et al., 2016). Once toxin production has been initiated, toxins accumulate in the cell and are released during late stages of growth (Karlsson et al., 2003;Rupnik et al., 2009;Di Bella et al., 2016). Some strains, such as epidemic ribotype (RT) 027 and RT078, also produce a third toxin called binary toxin [or C. difficile transferase (CDT)]. ...
Article
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Clostridioides difficile is often resistant to the actions of antibiotics to treat other bacterial infections and the resulting C. difficile infection (CDI) is among the leading causes of nosocomial infectious diarrhea worldwide. The primary virulence mechanism contributing to CDI is the production of toxins. Treatment failures and recurrence of CDI have urged the medical community to search for novel treatment options. Strains that do not produce toxins, so called non-toxigenic C. difficile , have been known to colonize the colon and protect the host against CDI. In this review, a comprehensive description and comparison of the immune responses to toxigenic C. difficile and non-toxigenic adherence, and colonization factors, here called non-toxin proteins, is provided. This revealed a number of similarities between the host immune responses to toxigenic C. difficile and non-toxin proteins, such as the influx of granulocytes and the type of T-cell response. Differences may reflect genuine variation between the responses to toxigenic or non-toxigenic C. difficile or gaps in the current knowledge with respect to the immune response toward non-toxigenic C. difficile . Toxin-based and non-toxin-based immunization studies have been evaluated to further explore the role of B cells and reveal that plasma cells are important in protection against CDI. Since the success of toxin-based interventions in humans to date is limited, it is vital that future research will focus on the immune responses to non-toxin proteins and in particular non-toxigenic strains.
... [109][110][111] Further, in residents of long-term care facilities it belongs to the most common infectious cause for healthcare-associated diarrhea. [112] In the US alone, 250.000 [113] people get infections by C. difficile and 15.000 -20.000 [113][114] people die due to these infections each year, hence the center for disease control and prevention (CDC) classifies C. difficile with an urgent threat level. [113] This threat level is caused by the emergence of a "hypervirulent" strain of C. difficile that is resistant against commonly used antibiotics to treat C. difficile. ...
... ILC1s protect against a broad range of intracellular pathogens, including bacteria, viruses, and protozoa. Clostridium difficile infection can cause severe colitis and diarrhea when the normal microbiota is perturbed after antibiotic treatment (149). ILCs appear to protect against C. difficile because Nfil À/À mice, which lack all ILC subsets, succumbed within 3 d, while WT and Nfil3 1/À heterozygous mice recovered (150). ...
Article
The critical role of commensal microbiota in regulating the host immune response has been established. In addition, it is known that host-microbial interactions are bidirectional, and this interplay is tightly regulated to prevent chronic inflammatory disease. Although many studies have focused on the role of classic T cell subsets, unconventional lymphocytes such as NKT cells and innate lymphoid cells also contribute to the regulation of homeostasis at mucosal surfaces and influence the composition of the intestinal microbiota. In this review, we discuss the mechanisms involved in the cross-regulation between NKT cells, innate lymphoid cells, and the gut microbiota. Moreover, we highlight how disruptions in homeostasis can lead to immune-mediated disorders.
... CDI frequently occurs post-broad-spectrum antibiotics treatment, which disrupts the gut microflora that would otherwise keep the proliferation of C. difficile in check. Symptoms of CDI range from mild cases of antibiotic-associated diarrhea to fatal pseudomembranous colitis (Kelly et al., 1994;Leffler and Lamont, 2009;Rupnik et al., 2009). The current paradigm for treating CDI is to administer additional antibiotics, mainly vancomycin and fidaxomicin. ...
Article
Clostridioides difficile is an enteric bacterium whose exotoxins, TcdA and TcdB, inactivate small GTPases within the host cells, leading to bloody diarrhea. In prior work, our group engineered a panel of potent TcdB-neutralizing designed ankyrin repeat proteins (DARPin) as oral therapeutics against C. difficile infection. However, all these DARPins are highly susceptible to digestion by gut-resident proteases, i.e. trypsin and chymotrypsin. Close evaluation of the protein sequence revealed a large abundance of positively charged and aromatic residues in the DARPin scaffold. In this study, we significantly improved the protease stability of one of the DARPins, 1.4E, via protein engineering. Unlike 1.4E, whose anti-TcdB EC50 increased >83-fold after 1-hour incubation with trypsin (1 mg/ml) or chymotrypsin (0.5 mg/ml), the best progenies-T10-2 and T10b-exhibit similar anti-TcdB potency as their parent in PBS regardless of protease treatment. The superior protease stability of T10-2 and T10b is attributed to the removal of nearly all positively charged and aromatic residues except those directly engaged in target binding. Furthermore, T10-2 was found to retain significant toxin-neutralization ability in ex vivo cecum fluid and can be easily detected in mouse fecal samples upon oral administration. Both T10-2 and T10b enjoy a high thermo- and chemo-stability and can be expressed very efficiently in Escherichia coli (>100 mg/l in shaker flasks). We believe that, in additional to their potential as oral therapeutics against C. difficile infection, T10-2 and T10b can also serve as a new generation DARPin scaffold with superior protease stability.
... The development of CDI is strongly associated with the alteration of bile acid metabolism and disruption of gut microbiota through the use of broad-spectrum antibiotics, allowing for optimal conditions for spore germination and subsequent colonization of the gut lumen (Shen, 2012). The clinical manifestations of CDI range in severity from mild diarrhea to life-threatening pseudomembranous colitis (Rupnik et al., 2009). The pathogenesis of CDI is strongly associated with the production of enterotoxin A (TcdA) and enterotoxin B and the presence of other virulence factors such as S-layer proteins and flagellin (Thelestam and Chaves-Olarte, 2000;Ausiello et al., 2006;Stevenson et al., 2015). ...
Article
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Clostridioides difficile infection (CDI) is frequently associated with intestinal injury and mucosal barrier dysfunction, leading to an inflammatory response involving neutrophil localization and upregulation of pro-inflammatory cytokines. The severity of clinical manifestations is associated with the extent of the immune response, which requires mitigation for better clinical management. Probiotics could play a protective role in this disorder due to their immunomodulatory ability in gastrointestinal disorders. We assessed five single-strain and three multi-strain probiotics for their ability to modulate CDI fecal water (FW)-induced effects on T84 cells. The CDI-FW significantly ( p < 0.05) decreased T84 cell viability. The CDI-FW-exposed cells also exhibited increased pro-inflammatory cytokine production as characterized by interleukin (IL)-8, C-X-C motif chemokine 5, macrophage inhibitory factor (MIF), IL-32, and tumor necrosis factor (TNF) ligand superfamily member 8. Probiotics were associated with strain-specific attenuation of the CDI-FW mediated effects, whereby Saccharomyces boulardii CNCM I-1079 and Lacticaseibacillus rhamnosus R0011 were most effective in reducing pro-inflammatory cytokine production and in increasing T84 cell viability. ProtecFlor™, Lactobacillus helveticus R0052, and Bifidobacterium longum R0175 showed moderate effectiveness, and L. rhamnosus GG R0343 along with the two other multi-strain combinations were the least effective. Overall, the findings showed that probiotic strains possess the capability to modulate the CDI-mediated inflammatory response in the gut lumen.
... The clinically most relevant form of C. difficile infections is pseudomembranous colitis, a severe inflammation of colon tissue accompanied by perturbation of the epithelial barrier and infiltration by immune cells (Abt et al., 2016;Guery et al., 2019). Many of the pathological consequences of the infection process are connected to the activities of two toxins (TcdA and TcdB) produced by C. difficile (Rupnik et al., 2009). Efficient colonization of the human colon by C. difficile require several traits, most of which are not well understood (Guarner and Malagelada, 2003;Britton and Young, 2014;Abt et al., 2016). ...
Article
Infections by the pathogenic gut bacterium Clostridioides difficile cause severe diarrheas up to a toxic megacolon and are currently among the major causes of lethal bacterial infections. Successful bacterial propagation in the gut is strongly associated with the adaptation to changing nutrition-caused environmental conditions; e.g. environmental salt stresses. Concentrations of 350 mM NaCl, the prevailing salinity in the colon, led to significantly reduced growth of C. difficile. Metabolomics of salt- stressed bacteria revealed a major reduction of the central energy generation pathways, including the Stickland-fermentation reactions. No obvious synthesis of compatible solutes was observed up to 24 h of growth. The ensuing limited tolerance to high salinity and absence of compatible solute synthesis might result from an evolutionary adaptation to the exclusive life of C. difficile in the mammalian gut. Addition of the compatible solutes carnitine, glycine-betaine, γ-butyrobetaine, crotonobetaine, homobetaine, proline-betaine and dimethylsulfoniopropionate (DMSP) restored growth (choline and proline failed) under conditions of high salinity. A bioinformatically-identified OpuF-type ABC-transporter imported most of the used compatible solutes. A long-term adaptation after 48 h included a shift of the Stickland fermentation-based energy metabolism from the utilization to the accumulation of L-proline and resulted in restored growth. Surprisingly, salt stress resulted in the formation of coccoid C. difficile cells instead of the typical rod-shaped cells, a process reverted by the addition of several compatible solutes. Hence, compatible solute import via OpuF is the major immediate adaptation strategy of C. difficile to high salinity-incurred cellular stress. This article is protected by copyright. All rights reserved.
... (O'Sullivan et al., 2013). After antibiotic treatment, virulent strains of C. difficile can colonize the gut and synthesize toxins, shedding spores and causing illnesses, ranging from mild diarrhea to fulminant relapsing diarrhea and pseudomembranous colitis (Rupnik et al., 2009). During the use of antibiotics, strategies aimed at restoring the microbiota have been studied, particularly the use of probiotics to adjust the dysbiosis in the bifidobacteria population and the change in gut microbiota after antibiotic treatment. ...
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The gastrointestinal (GI) microbiota is one of the most complex ecosystems in nature that are mainly comprised of bacteria and other microbes like fungi, protozoa, and viruses. More than 1000 bacterial species have been reported in the gut microbiome, of which most of these species belong to Firmicutes (31.1%), Proteobacteria (29.5%), Actinobacteria (25.9%), or Bacteroidetes (7.1%) phylum. A symbiotic relationship, which plays a critical role in host health, exists between intestinal microflora and its host. With aging, the intestinal microbiota profile changes are observed, generally characterized by the decrease in biodiversity, carriage of commensals, and enrichment of opportunistic pathogens. The dysbiosis associated with aging in the gut microbiota increases the risk of several diseases. Probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host" and play crucial functions in improving gut health and disease in all age groups, particularly the elderly induvial. This review focuses on the promising effects of probiotics on slowing down the aging process, treating age-related diseases, and improving the quality of life in light of the current clinical studies.
... CA and CDCA affected folding of different subsets of bacterial proteins, showing antibacterial function and reducing the diversity of gut microbiota (Dawson and Karpen 2015). Glycine, CA and TCA are well known to facilitate in vitro growth of Clostridium difficile, a pathogen responsible for significant morbidity of IBD and mortality in patients (Rupnik et al. 2009;Sorg and Sonenshein 2008). CA can be converted to DCA by bacterial dihydroxylation, which, combined with DCA formation via deconjugating of GDCA and TDCA, may result in a bile acid pool with more DCA that is more hydrophobic and toxic (Ridlon et al. 2006). ...
Article
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Conjugated bile acids are synthesized in liver and subsequently secreted into the intestinal lumen from which they are actively reabsorbed and transported back to liver. The efficient enterohepatic circulation of conjugated bile acids is important to maintain homeostasis. The mycotoxin deoxynivalenol (DON) is a fungal secondary metabolite that contaminates cereal food. Upon human exposure, it can cause intestinal dysfunction. We explored the effects of DON exposure on the intestinal absorption of conjugated bile acids and the expression of bile acid transporters using an in vitro model based on Caco-2 cell layers grown in transwells. Our study shows that the transport rate of taurocholic acid (TCA) is decreased after 48-h pre-exposure of the Caco-2 cells to 2 µM DON, which is a realistic intestinal DON concentration. Exposure to DON downregulates expression of the genes coding for the apical sodium-dependent bile acid transporter (ASBT), the ileal bile acid-binding protein (IBABP) and the organic solute transporter α (OSTα), and it counteracts the agonist activity of Farnesoid X receptor (FXR) agonist GW4064 on these genes. In addition, the transport of ten taurine or glycine-conjugated bile acids in a physiological relevant mixture by the intestinal Caco-2 cell layers was decreased after pre-exposure of the cells to DON, pointing at a potential for DON-mediated accumulation of the conjugated bile acids at the intestinal luminal side. Together the results reveal that DON inhibits intestinal bile acid reabsorption by reducing the expression of bile acid transporters thereby affecting bile acid intestinal kinetics, leading to bile acid malabsorption in the intestine. Our study provides new insights into the hazards of DON exposure.
... The frequency of Clostridioides difficile infections (CDIs) has been increasing worldwide for more than 15 years (Rupnik et al., 2009). It is assumed that there are at least 1,500 severe CDIs in Germany per year, with regional incidences varying between 0.2 (State of Saarland) and 6.6 diseases/100,000 inhabitants (State of Saxony-Anhalt). ...
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With an annual incidence of 250-300 per 100,000 inhabitants, reactive arthritis is not uncommon. However, the fact that Clostridioides difficile infection (CDI) can also lead to this complication is largely unknown. We report on a 69-years-old man who developed reactive arthritis of his right knee joint one week after antibiotic-associated diarrhea with evidence of C. difficile of the hypervirulent ribotype 027. His female partner also became infected with C. difficile ribotype 027, but did not develop reactive arthritis. The further investigation showed that the patient - in contrast to his partner - was HLA-B27 positive and had strong antibody levels against C. difficile. The case history together with the review of 45 other cases described so far shows that C. difficile can also lead to reactive arthritis. C. difficile-associated reactive arthritis (CDARA) is characterized by the fact that patients suffer from diarrhea or colitis after taking antibiotics, toxigenic C. difficile or only the toxins are detectable in the stool and there are no other explanations for the arthritis and diarrhea.
... Analyzing a total of 121 patients in a rural area of Germany, we identified C. difficile as a likely cause of diarrhea in 24.0% of them. Confirming previous studies, CDI had a significant correlation with hospital-acquired infection in our cohort (Rupnik et al., 2009;Leffler and Lamont, 2015). Our rate of community-acquired CDI is also similar to the results of previous studies which reported a percentage of 20-29% for community-acquired infection (Clohessy et al., 2014;Gupta and Khanna, 2014). ...
Article
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Nosocomial infections with Clostridioides (Clostridium) difficile have become an emergent health threat. We sought to define risk factors for a C. difficile infection (CDI) beyond the widely known ones, such as antibiotic use and prior hospital stay. We therefore focused on a group of patients with diarrhea in order to identify risk factors for C. difficile infection among this symptomatic cohort. A total of 121 hospitalized patients from Seesen/Germany with diarrhea were included who submitted a stool sample and were interviewed about their socio-demographic background, lifestyle and state of health using a standardized questionnaire. Antibiotic potential of diuretics was examined by agar diffusion test. C. difficile was identified in 29 patients resulting in a prevalence of 24.0%. The infection was hospital-acquired in most cases (p < 0.001, 82.1%; n = 23/28, versus 29/91, 31.9%). The generally accepted risk factor previous antibiotic use was confirmed in this study (p = 0.002, n = 23/28 CDI patients, 82.1%, versus n = 44/91 non-CDI patients, 48.4%). The following additional risk factors were identified: regular consumption of proton pump inhibitors; PPI (p = 0.011, n = 24/29, 82.8% vs. n = 52/92, 56.5%), CDI patients ate less vegetables (p = 0.001, n = 12/29, 41.4% vs. 69/92, 75.0%). The intake of the diuretic agent torasemid in patients with CDI (p = 0.005, n = 18/29, 62.1%) was higher than in patients without (n = 30/92, 32.6%). More patients with CDI had to undergo a surgery in the previous year (p = 0.022, n = 13/29, 44.8% vs. n = 21/92, 22.8%) and held more birds (p = 0.056, n = 4/29, 13.8%) than individuals of the negative group (n = 3/92, 3.3%). In conclusion, although no antibiotic potential was detected in diuretics, especially torasemid seems to have significant influence for the occurrence of a CDI as well as a nutrition poor in vegetables. A diet rich in vegetables represented a fourfold lower risk for a CDI (OR 0.240, CI (0.0720 - 0.796]).
... The intestinal pathogen Clostridioides difficile is a strictly anaerobic bacterium and causes one of the most frequent hospital-acquired infections in developed countries called CDI for Clostridioides difficile infection. C. difficile produces two major toxins (toxins A and B) that provoke diarrhea in the first instance (Thomas et al., 2003), and in more advanced and serious cases pseudomembranous colitis, toxic megacolon and possibly even an intestinal perforation leading to sepsis (Rupnik et al., 2009). The bacterium is capable of forming extremely resistant spores that persist antibiotic treatment resulting in very high relapse rates. ...
Article
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The anaerobic bacterium Clostridioides difficile represents one of the most problematic pathogens, especially in hospitals. Dysbiosis has been proven to largely reduce colonization resistance against this intestinal pathogen. The beneficial effect of the microbiota is closely associated with the metabolic activity of intestinal microbes such as the ability to transform primary bile acids into secondary ones. However, the basis and the molecular action of bile acids (BAs) on the pathogen are not well understood. We stressed the pathogen with the four most abundant human bile acids: cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA) and lithocholic acid (LCA). Thin layer chromatography (TLC), confocal laser scanning microscopy (CLSM), and electron microscopy (EM) were employed to track the enrichment and destination of bile acids in the bacterial cell. TLC not only revealed a strong accumulation of LCA in C. difficile , but also indicated changes in the composition of membrane lipids in BA-treated cells. Furthermore, morphological changes induced by BAs were determined, most pronounced in the virtually complete loss of flagella in LCA-stressed cells and a flagella reduction after DCA and CDCA challenge. Quantification of both, protein and RNA of the main flagella component FliC proved the decrease in flagella to originate from a change in gene expression on transcriptional level. Notably, the loss of flagella provoked by LCA did not reduce adhesion ability of C. difficile to Caco-2 cells. Most remarkably, extracellular toxin A levels in the presence of BAs showed a similar pattern as flagella expression. That is, CA did not affect toxin expression, whereas lower secretion of toxin A was determined in cells stressed with LCA, DCA or CDCA. In summary, the various BAs were shown to differentially modify virulence determinants, such as flagella expression, host cell adhesion and toxin synthesis. Our results indicate differences of BAs in cellular localization and impact on membrane composition, which could be a reason of their diverse effects. This study is a starting point in the elucidation of the molecular mechanisms underlying the differences in BA action, which in turn can be vital regarding the outcome of a C. difficile infection.
... The two large clostridial toxins, TcdA and TcdB, are the main virulent factors of the pathogen. In addition, some strains can possess a third toxin called binary toxin (CDT) [8]. Several nontoxin factors involved in the virulence and infection processes have been also described, including flagella, cell wall proteins, surface layer proteins, and fibronectin-binding proteins [9,10]. ...
Article
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The full text of the paper is available from: https://doi.org/10.1016/j.anaerobe.2021.102476. Objective The motility and genotype of the flagellin fliC and fliD genes were investigated in 82 Clostridioides difficile isolates belonging to the ribotypes (RTs): 027 (n = 41), 176 (n = 17), 023 (n = 8), 017 (n = 6) and 046 (n = 10). The reference C. difficile strains 630 and M120 were included as controls for the motility assay. Methods A Multiple Locus Variable-number Tandem Repeat Analysis (MLVA) was used to exclude the genetic relatedness of C. difficile isolates belonging to the same RT. The variability of the fliC and fliD genes was determined by PCR-restriction fragment length polymorphism (RFLP) analysis and Sanger sequencing. The motility assay was carried out with 0.175% BHI agar tubes and BHI solid media plates with 0.4% agar. Results The highest motility was observed in C. difficile RT023 isolates (p < 0.01), followed by RTs 027 and 176. C. difficile isolates of RTs 017 and 046 were less motile than RTs 027, 176 and 023 (p < 0.01). The fliC and fliD genes were present in all clinical isolates irrespective of the motility results. In the fliC gene analysis, four different RFLP groups were identified (I, II, VII, X). The fliC group VII was identified in two RTs (027 and 176), whereas the remaining three groups (I, II and X) belonged to a single RT 046, 017 and 023, respectively. The fliD gene analysis identified four new RFLP groups (a, b, c and d). Conclusions C. difficile RT023 is highly motile and its motility is comparable to the hypervirulent RT027 and its genetic relative RT176.
... Clostridium difficile has been identified as one of the microorganisms that affects humans and animals as a result of contamination. Typical symptoms caused by this strain include pseudo-membrane colitis and abdominal pain (Rupnik et al. 2009). ...
... Clostridium difficile is an anaerobic Gram-positive bacillus that infects the colon of susceptible patients, mainly in hospital settings, but also increasingly in the community. C. difficile infections (CDI) are typified by severe diarrhea, pseudomembranous colitis, and in extreme cases colonic rupture, sepsis and death Rupnik et al., [22]. ...
Article
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Clostridia are obligately anaerobic, spore-forming bacilli that, at least in the early stages of growth, stain gramme positive. Clostridia produce greater toxins than any other bacterium genus, and pathogenic clostridia are typically diagnosed by their unique toxins. Clostridium spp. has been found to have more than 20 toxins and other extracellular proteins that contribute to virulence, such as spread factors and proteolytic enzymes. Botulinum and tetanus toxins are the most potent poisons ever discovered. Clostridium botulinum neurotoxins are the most potent acute toxins identified, and they are the cause of the neuroparalytic illness botulism. Such toxins work by inhibiting presynaptic nerve terminal neurotransmission in the peripheral and central nervous systems. Other clostridia toxins have different modes of action, such as tissue destruction, hemolysis, diarrhoea, or generating an overactive immunological response in the recipient. On non-integrative lysogenic bacteriophages or plasmids, the genes coding for numerous clostridial toxins are found. Protein secretory processes in Clostridia are poorly understood. It has remained a mystery as to how the tetanus toxin, which lacks a normal N-terminal signal peptide, is exported until today. Typical PAI are DNA segments that are found in pathogenic bacteria's genomes but not in nonpathogenic strains of the same or similar species.
... C. difficile is recognized as an urgent threat by the Centers for Disease Control and Prevention (CDC) and has been conservatively estimated at over 220,000 cases in hospitalized patients and nearly 13,000 deaths within the United States annually (1). The disruption of natural colonic microbiota following antibiotic use is the leading risk factor for C. difficile infection (CDI), and recurrent infections occur in ∼35% of patients (2)(3)(4). Two toxins, TcdA and TcdB, are the primary virulence factors for symptomatic infection (5). However, virulence is also attributed by other factors, including the cytolethal distending toxin, sporulation, flagella, and adhesins (6)(7)(8)(9)(10)(11)(12). ...
Article
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Significance Clostridioides difficile infections are the most common source of hospital-acquired infections and are responsible for an extensive burden on the health care system. Strains of the C. difficile species comprise diverse lineages and demonstrate genome variability, with advantageous trait acquisition driving the emergence of endemic lineages. Here, we present a systems biology analysis of C. difficile that evaluates strain-specific genotypes and phenotypes to investigate the overall diversity of the species. We develop a strain typing method based on similarity of accessory genomes to identify and contextualize genetic loci capable of discriminating between strain groups.
... the burden of CDI cases in Korea has been continually increasing [4]. C. difficile shows various clinical presentations, which range from asymptomatic colonisation to a life-threatening infection [5,6]. The prevalence of asymptomatic colonisation with C. difficile is 3% to 26% and 5% to 7% in acute care hospitals [7][8][9] and long-term care facilities [10,11], respectively. ...
Article
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Background Given the increasing incidence of Clostridioides difficile infections in Korea, there has been an increase in inappropriate testing for C. difficile , which has rendered overdiagnosis of asymptomatic colonisers common. We aimed to investigate the appropriateness of C. difficile testing and the related factors. Methods We retrospectively reviewed the medical records of patients who were admitted to a 1300-bed tertiary-care teaching hospital in Korea and were tested for C. difficile infection from September 2019 to November 2019. We performed logistic regression analysis to investigate factors related to inappropriate testing. Further, a survey was conducted on physicians to assess the knowledge and ordering patterns of C. difficile testing. Results We included 715 tests from 520 patients in the analysis. Testing was classified as hospital-onset and community-onset and subclassified as appropriate and inappropriate following an algorithmic method. Among the 715 tests, 576 (80.6%) and 139 (19.6%) tests were classified as hospital-onset and community-onset, respectively. Among the hospital-onset tests, 297 (52%) were considered inappropriate. The risk of inappropriate testing increased when C. difficile tests were conducted in the emergency room (OR 24.96; 95% CI 3.12–199.98) but decreased in intensive care units (OR 0.36, 95% CI 0.19–0.67). The survey was conducted on 61 physicians. Internal medicine physicians had significantly higher scores than non-internal medicine physicians (7.1 vs. 5.7, p = 0.001). The most frequently ordered combination of tests was toxin + glutamate dehydrogenase (47.5%), which was consistent with the ordered tests. Conclusion Almost half of the C. difficile tests were performed inappropriately. The patient being located in the emergency room and intensive care unit increased and decreased the risk of inappropriate testing, respectively. In a questionnaire survey, we showed that internal medicine physicians were more knowledgeable about C. difficile testing than non-internal medicine physicians. There is a need to implement the diagnostic stewardship for C. difficile , especially through educational interventions for emergency room and non-internal medicine physicians.
... C. difficile is intrinsically resistant to many antibiotics, limiting treatment options (26). This problem is compounded by the dissemination of hypervirulent strains such as R20291 (BI/NAPI/027) (27)(28)(29). The current treatment options of C. difficile infection (CDI) including metronidazole, vancomycin and fidaxomicin are not fully effective (30, 31) with a recurrence FIG 3 Antitoxin IgG isotypes and antitoxin neutralizing titers of sera from mice orally immunized with NTCD_Tcd169 spores. ...
Article
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Clostridioides difficile is an enteric pathogen, and symptoms of C. difficile infection (CDI) are mainly by two exotoxins TcdA and TcdB. Active vaccination is cost-effective approach to prevent CDI and high rates of recurrence.
... CDI is recognised as an important antibioticassociated infection, which is easily transmissible by spores and occurring both in the healthcare and community setting. 4 Symptoms range from mild diarrhoea to life-threatening toxic megacolon. ...
Article
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Background During the COVID-19 pandemic, several factors, such as improved hand hygiene, social distancing, and restricted hospital referral, may have had an influence on the epidemiology of Clostridioides difficile infections (CDI). Methods The annual CDI incidence rate of nine hospitals participating in the Dutch sentinel CI surveillance with complete data was compared between 2020 and the previous five surveillance years. Trends in characteristics of hospitalised CDI patients in 21–24 participating hospitals were compared between the first (March 13–May 12, 2020) or second Dutch COVID-19 wave (September 17, 2020-January 1, 2021) and the same calendar periods in 2015 through 2019. All analyses were adjusted for trend changes over time. Findings The annual CDI incidence rate in 2020 was lower compared to previous years. During the second wave, the percentage of CDI patients with severe CDI was higher compared to earlier (25·8% in 2020 vs 17·9% in 2015-2019 (RR 1·6; 95%CI 1·1-2·3)). After adjustment for delayed C. difficile diagnostics (≥8 days from start symptoms), the increase disappeared. Delayed C. difficile diagnostics was indeed more common during the second wave (RR 1·7; 95%CI 1·1-2·6), but only for community-onset CDI (CO-CDI). Interpretation This study shows that a higher percentage of severe CDI cases was observed during the second COVID-19 wave. This may partially be caused by delayed diagnostics, potentially due to decreased visits to a physician or restricted hospital referral for CO-CDI patients. Funding Dutch ministry of Health.
... Based on the increased mortality of infected oysters under low salinity, it was speculated that the enhanced oyster inflammation would still have adverse effects on oyster health in the later stage. Changes in intestinal microflora are closely related to immune status, as demonstrated in mice infected with Clostridium difficile (102). Altered host immune responses to multiple stressors may affect intestinal microbial composition, interspecific interactions, and microbial community mediated biological functions (103). ...
Article
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A sudden drop in salinity following extreme precipitation events usually causes mass mortality of oysters exposed to pathogens in ocean environment. While how low salinity stress interacts with pathogens to cause mass mortality remains obscure. In this study, we performed an experiment by low salinity stress and pathogen infection with Vibrio alginolyticus to investigate their synergistic effect on the mortality of the Pacific oyster toward understanding of the interaction among environment, host, and pathogen. We showed that low salinity stress did not significantly affect proliferation and virulence of V. alginolyticus, but significantly altered microbial composition and immune response of infected oysters. Microbial community profiling by 16S rRNA amplicon sequencing revealed disrupted homeostasis of digestive bacterial microbiota with the abundance of several pathogenic bacteria being increased, which may affect the pathogenesis in infected oysters. Transcriptome profiling of infected oysters revealed that a large number of genes associated with apoptosis and inflammation were significantly upregulated under low salinity, suggesting that low salinity stress may have triggered immune dysregulation in infected oysters. Our results suggest that host-pathogen interactions are strongly affected by low salinity stress, which is of great significance for assessing future environmental risk of pathogenic diseases, decoding the interaction among environment, host genetics and commensal microbes, and disease surveillance in the oyster.
... In this preliminary in vitro study, we observed that L. (Czepiel et al. 2019), allowing the toxins to enter the laminar propria and submucosa, where they induce the production of proinflammatory and cytotoxic molecules, such as IL-8 (Boonma et al. 2014). Increased IL-8 secretion by intestinal epithelial cells causes a massive influx of neutrophils into the colonic mucosa, resulting in epithelial damage due to inflammatory edema (Rupnik et al. 2009). We observed multiple protective effects of L. plantarum E51 on C. difficile infection, suggesting that the mechanisms underlying the protective effects may involve multiple steps in C. difficile pathogenesis. ...
Article
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Clostridioides difficile (C. difficile) infection is associated with high morbidity and mortality. This study aimed to evaluate the protective effect of Lactiplantibacillus plantarum E51 (L. plantarum E51) on C. difficile infection using the Caco-2 monolayer in vitro model. Caco-2 cells were infected with C. difficile in the presence/absence of L. plantarum E51 or Lacticaseibacillus rhamnosus GG (LGG). Caco-2 intestinal barrier functions, such as monolayer integrity, IL-8 secretion, and tight junction protein expression, were quantified to investigate the extent to which L. plantarum E51 protected against C. difficile infection in vitro. Furthermore, inhibition of C. difficile adhesion to Caco-2 cells by L. plantarum E51 was explored using competition, exclusion, and displacement assays. The results indicated that L. plantarum E51 inhibited C. difficile growth, ameliorated C. difficile-caused decrease in transepithelial/ transendothelial electrical resistance, attenuated C. difficile-induced IL8 secretion, and upregulated claudin-1 protein expression that was inhibited by C. difficile. Moreover, L. plantarum E51 suppressed C. difficile adhesion to Caco-2 cells. In conclusion, these findings demonstrated that L. plantarum E51 substantially protected against C. difficile-induced damages on intestinal barrier functions in Caco-2 cells. The probiotic potential of L. plantarum E51 against C. difficile infection warrants further investigation.
... Not only but also, antibiotic treatment in adult perturbs the intestinal microbiota, leading to an immediate reduction in microbial abundance and species diversity (Antonopoulos et al., 2009) and suppression of the innate immune system (Bartlett, 2006;Rupnik et al., 2009). Several studies indicate that the gut microbiota of healthy young adults is resilient after four days of broadspectrum antibiotic treatment with recovery of most bacterial communities in approximately 6 months, with an individualized response of the human distal gut microbiota due to this repeated antibiotic perturbation (Les whereas repeated perturbations may be particularly likely to cause such shifts, even when the community seems to have recovered from the initial perturbation (Paine et al., 1998). ...
Thesis
The human intestinal microbiota is composed of several types of microorganisms, including bacteria, archaea, fungi, unicellular eukaryotes and viruses. Among them, bacteria are the most diverse and abundant with a gene catalog 150 times larger than the genes present in the human genome, which represents a tremendous metabolic potential. These bacteria actively participate in the maintenance of intestinal homeostasis. Dysbiosis of the gut microbiota could be observed at course of many human pathologies, particularly inflammatory diseases intestinal chronic diseases (IBD), such as Crohn's disease (CD) or Ulcerative colitis (UC). These dysbiosis could contribute to the onset and progression of diseases. For example, gut microbiota transplantation experiments in murine model have allowed to show that a dysbiotic microbiota is sufficient to induce chronic inflammation in the colon and thus lead to the development of a metabolic syndrome or colitis. Different intervention strategies, including fecal transplantation, administration of probiotics or even special nutritional diets have been developed to act on the microbial communities of the digestive tract and to restore homeostasis of host tissues. The success of some interventions like Fecal transplantation represent a proof of concept in humans that acting on the composition of the intestinal microbiota is a strong lever to resolve certain physio pathological situations associated with gut microbiota dysbiosis. Diet is another important method for modulating the gut microbiota since it is the most important factor influencing its composition. In fact, the nutrients ingested can act directly on the composition of the microbiota by serving as substrates for microorganisms and indirectly by modulating intestinal homeostasis and components of the immune system associated, themselves contributing to regulate the composition microbiota. It is expected that ingestion of these beneficial microorga nisms can stimulate the immune system, promote intestinal homeostasis and to some extent contribute to the balance of the microbiota intestinal. The use of probiotic microorganisms is found to be very effective in some studies to treat different physiopathological situations (colitis, metabolic syndrome) in laboratory model organisms (rats, mice), however the use of these same probiotics in humans have given relatively disappointing clinical results, with poorly reproducible results across cohorts of patients. Except for the treatment of antibiotic-associated diarrhea. These discrepancies in results between pre-clinical models and clinical trials encourage better characterization of the molecular mechanisms used by probiotics to exert their beneficial effects and especially better understand the relationship of these probiotic microorganisms with the resident microbiota and diet.Among the different rising intervention strategies practiced nowadays in the purpose to shape the microbiota, a growing interest is given to other dietary interventions, like caloric restriction (CR) which has demonstrated several beneficial effects on various physiological systems, including the gastro-intestinal system, by modulating the innate and adaptative immune responses. In fact, emerging evidence suggests that the immune system function might be heavily influenced by the sensing of nutrient, reinforcing the idea that diet can deeply influence the inflammatory responses.
... Further, one study reported a decrease in Clostridium difficile abundance upon exercise [62]. This bacterium is a major source of infectious diarrhea associated with toxin production in the host's gastrointestinal tract [76,77], especially in the elderly [78][79][80] and obese individuals [81,82]. These observations suggest that moderate exercise has a positive effect on the abundance of Clostridium bacteria. ...
Article
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Background Gut microbiota is considered to have a great impact on human health and disease. While it is widely recognized that the gut microbiota of healthy individuals differs from those with obesity, inflammatory bowel disease, metabolic syndrome, and other chronic diseases, the alterations of gut microbiota with physical activity are not fully understood. Accordingly, we performed this systematic review to address the question regarding the effects of mild and intense exercise on the gut microbiota in humans. Methods The comparative analyses of gut microbiota were conducted following the PRISMA protocol to determine the differences in the active vs. non-active individuals (phenotypes) ( n = 11), including the influence of physical activity intervention on the human gut microbiota ( n = 13); the differences in the gut microbiota of athletes vs. non-athletes ( n = 8); and the microbiota status at different stages of athletic performance or intervention ( n = 7), with various of physical activities, sport disciplines, and activity duration. Literature searches were completed using four databases: PubMed, Web of Science, Scopus, and EBSCO, and 2090 articles were retrieved by using appropriate keywords. The low heterogeneity of the studies hasn’t allowed us to prepare a meta-analysis. After excluding 2052 articles, we ultimately selected 38 articles that met the eligibility criteria for this review. Results The data analyses revealed that in non-athletes rising physical activity markedly influenced the relative abundance of short-chain fatty acid (SCFA). Aerobic training that lasted 60 min, and physical activity that characterized 60% HRmax or more also influenced beta diversity indexes. The results showed that athletes harbor a more diverse type of intestinal microflora than non-athletes, but with a relatively reduced abundance of SCFA- and lactic acid-producing bacteria, thereby suggesting an adverse effect of intense exercise on the population of gut microbiota. Conclusion It is concluded that the level of physical activity modulates the gastrointestinal microbiota in humans. For a long period, increasing the intensity and volume of exercise may lead to gut dysbiosis. Perhaps, proper supplementation should be considered to keep gut microbiota in large biodiversity and richness, especially under unfavorable gut conditions associated with intense exercise. Trial registration Prospero CRD42021264064.
... Große Mengen Bakterien und Sporen werden über dünnflüssigen Stuhl von Infizierten ausgeschieden. Sporen, als Überdauerungsform der Bakterien resistent gegen Wärme, Austrocknung und zahlreiche Chemikalien, wie auch viele Desinfektionsmittel, Auch wenn ältere, hospitalisierte Patienten nach wie vor als Hauptrisikogruppe gelten98 , sei an dieser Stelle ebenso auf einen Anstieg bei jüngeren Patienten ohne klassische Betalaktamase-Inhibitor mit einem besonderen Risiko behaftet zu sein106 . Die Gefahr zu erkranken ist im ersten Monat nach Antibiotikagabe am höchsten 41 . ...
... C. difficile is an anaerobic, spore-forming, Gram-positive bacterium, identified as a causative agent of antibiotic-associated pseudomembranous colitis [51]. Infection comprises a spectrum of clinical manifestations that range from asymptomatic carriage or mild symptoms to life-threatening conditions (toxic megacolon, colonic perforation) and death [52]. ...
Article
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Clostridioides difficile (C. difficile) represents a major health burden with substantial economic and clinical impact. Patients with inflammatory bowel diseases (IBD) were identified as a risk category for Clostridioides difficile infection (CDI). In addition to traditional risk factors for C. difficile acquisition, IBD-specific risk factors such as immunosuppression, severity and extension of the inflammatory disease were identified. C. difficile virulence factors, represented by both toxins A and B, induce the damage of the intestinal mucosa and vascular changes, and promote the inflammatory host response. Given the potential life-threatening complications, early diagnostic and therapeutic interventions are required. The screening for CDI is recommended in IBD exacerbations, and the diagnostic algorithm consists of clinical evaluation, enzyme immunoassays (EIAs) or nucleic acid amplification tests (NAATs). An increased length of hospitalization, increased colectomy rate and mortality are the consequences of concurrent CDI in IBD patients. Selection of CD strains of higher virulence, antibiotic resistance, and the increasing rate of recurrent infections make the management of CDI in IBD more challenging. An individualized therapeutic approach is recommended to control CDI as well as IBD flare. Novel therapeutic strategies have been developed in recent years in order to manage severe, refractory or recurrent CDI. In this article, we aim to review the current evidence in the field of CDI in patients with underlying IBD, pointing to pathogenic mechanisms, risk factors for infection, diagnostic steps, clinical impact and outcomes, and specific management.
Chapter
C. difficile is a gram-positive, anaerobic spore-forming bacterium considered as the leading cause of antibiotic-associated diarrhea and pseudomembranous colitis. C. difficile is a foremost problem in hospitals, where cases can be caused by community-acquired strains, as well as by nosocomial spread. The epidemiology of C. difficile has changed considerably along the years with the variety of strains (ribotypes) from different sources, hence an accurate diagnosis of Clostridioides difficile infection (CDI) is important not only for patient care but also for epidemiology and disease research purposes. Here we make a review of the precise molecular typing technics used to better understanding of CDI epidemiology. Initially called Bacillus difficilis, due to the difficulty in its cultivation, the species is currently known as Clostridioides difficile (C. difficile). It was renamed after a new categorization of microorganisms belonging to the genus Clostridium, based on 16S ribosomal RNA. Ezaki [1] proposed a regrouping of C. difficile, due to its 94.7% similarity in the gene sequence with Clostridium mangenotii, belonging to the Peptostreptococcaceae family. However, this new reclassification generated conflict due to the various acronyms adopted over the years to refer to diseases associated with C. difficile. Therefore, Lawson et al. [2] proposed a new modification in the nomenclature of both the Clostridium difficile and the Clostridium mangenotii, for Clostridioides, with C. difficile as the main representative of this genus.
Article
Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections.
Chapter
The human body harbors diverse microbiota in different parts of the body. Most of these (more than 70%) microbiota are present in the gastrointestinal tract and are referred as “gut microbiome.” The gut microbiome performs many metabolic functions such as production of lipid and vitamins and control of glucose and lipid state in the body. It is also involved in providing antiinflammatory and anticarcinogenic effect and prevents colonization of invading microbes. Drug resistance in microbes is presently in a taxing situation. Bacterial strains have evolved numerous mechanisms to combat different antibiotics. Unrestrained use of antibiotics provides opportunity for the gut microbiome to come in direct contact with a high concentration of therapeutic drugs for a longer time, providing the environment for generation of resistance for better survival. Colonization of these resistant microbes leads to inflammation of the gastrointestinal tract and metabolic and vascular disorders in human. Resistant infections which are expensive and harder to treat pose an alarming threat to the public health. The chapter provides an overview of the health and economical effects of rising and spreading resistance in the gut microbiota and means to prevent the generation of resistance.
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Background: Nonalcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease with increasing prevalence worldwide. Clostridioides difficile infection (CDI) remains the most common cause of nosocomial diarrhea in developed countries. Aim: To assess the impact of NAFLD on the outcomes of hospitalized patients with CDI. Methods: This study was a retrospective cohort study. The Nationwide Inpatient Sample database was used to identify a total of 7239 adults admitted as inpatients with a primary diagnosis of CDI and coexisting NAFLD diagnosis from 2010 to 2014 using ICD-9 codes. Patients with CDI and coexisting NAFLD were compared to those with CDI and coexisting alcoholic liver disease (ALD) and viral liver disease (VLD), individually. Primary outcomes included mortality, length of stay, and total hospitalization charges. Secondary outcomes were in-hospital complications. Multivariate regression was used for outcome analysis after adjusting for possible confounders. Results: CDI with NAFLD was independently associated with lower rates of acute respiratory failure (2.7% vs 4.2%, P < 0.01; 2.7% vs 4.2%, P < 0.05), shorter length of stay (days) (5.75 ± 0.16 vs 6.77 ± 0.15, P < 0.001; 5.75 ± 0.16 vs 6.84 ± 0.23, P <0.001), and lower hospitalization charges (dollars) (38150.34 ± 1757.01 vs 46326.72 ± 1809.82, P < 0.001; 38150.34 ± 1757.01 vs 44641.74 ± 1660.66, P < 0.001) when compared to CDI with VLD and CDI with ALD, respectively. CDI with NAFLD was associated with a lower rate of acute kidney injury (13.0% vs 17.2%, P < 0.01), but a higher rate of intestinal perforation (P < 0.01) when compared to VLD. A lower rate of mortality (0.8% vs 2.7%, P < 0.05) but a higher rate of intestinal obstruction (4.6% vs 2.2%, P = 0.001) was also observed when comparing CDI with NAFLD to ALD. Conclusion: Hospitalized CDI patients with NAFLD had more intestinal complications compared to CDI patients with VLD and ALD. Gut microbiota dysbiosis may contribute to the pathogenesis of intestinal complications.
Article
Objectives Patients with Clostridioides difficile infection (CDI) who receive treatment at outpatient infusion centers (OICs) pose a risk for spore transmission. We investigated C. difficile contamination in the environment of CDI and non-CDI patients and evaluated the effectiveness of standard cleaning. Methods This is a multicenter, non-conventional study including 8 OICs between October 2019 and December 2020. Samples were collected at baseline, after infusion, and after cleaning CDI and non-CDI areas. Cleaning was performed using hypochlorite and non-hypochlorite products for CDI and non-CDI, respectively. Samples were cultured for toxigenic C. difficile and strain-typed via fluorescent PCR ribotyping and whole-genome sequencing. Results The overall C. difficile contamination rate was 7.9% (156/1969) with 8.1% in patient and 5.6% in non-patient care areas, respectively. For CDI areas, contamination rates were 5.9% at baseline, 15.0% after infusion, and significantly reduced to 6.2% after cleaning (P = 0.004). For non-CDI areas, contamination was similar at baseline (9.5%), after infusion (7.6%), and after cleaning (4.3%). The difference in C. difficile-positive samples after infusion was significant for CDI vs. non-CDI (15.0% vs. 7.6%, P = 0.004). Overall contamination was 11.5% for floors, 7.9% for infusion chairs, and 3.8% for equipment (P = 0.001). The most frequent ribotypes were F014-020 (42.6%), F106 (15.6%), F255 (6.1%), F001 (5.2%) and F027 (3.5%). Cleaning resulted in elimination of F106, F255, F001, F027 and partial reduction of F014-020. Conclusions Environmental C. difficile contamination was increased after CDI infusions and significantly reduced after cleaning with a hypochlorite solution, reducing the potential risk of spore transmission to others.
Chapter
Bartonella spp. is an arthropod-vectorized bacterial genus responsible for a wide array of vector-borne diseases. Although potentially lethal, Bartonella spp. has remained for years out of scope of clinicians. While challenged by the fastidious nature of Bartonella spp., the development of molecular tools has allowed identifying an increasing number of fully or partially characterized new Bartonella species, contributing to the knowledge of its epidemiology and the further understanding of its pathogenicity. The present chapter summarizes the most relevant approaches to type Bartonella spp.
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Microbiota is an integral component of the intestinal tract and plays a significant role in health status of fish. However, diet and feeding habits are the key factors affecting the intestinal microbiota. Here, a 90-day feeding trial was conducted to investigate the effects of a plant-based β-mannanase supplemented diet on the growth, gut microbiome, and mRNA level of key digestion and immunity-related genes of common carp (Cyprinus carpio). Fish were evenly distributed in 3 groups: control, A1 and A2, and fed 35% CP supplemented with β-mannanase at the rate of 0, 500, and 1000 units/kg diet respectively. At the end of the feeding trial, the intestinal microbiota was profiled by sequencing the v4 region of bacterial 16S rRNA and internal transcribed spacer (ITS) regions of fungal 18S rRNA. Results indicated improved growth performance, changes in richness and diversity of intestinal microbiota and up-regulation of intestinal digestion (Amy, Lip, Tryp, FAS, FABP), and immunity-related (SOD, NK-lys, Def, Lys, IL1-β) genes of A1 and A2 groups of fish as compared to control. This study first time demonstrates that β-mannanase in a plant-based diet could improve the intestinal health of C. carpio via modulation of gut microbiota and up-regulation of host digestion and immunity-related genes.
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Background Clostridioides difficile infection can be a significant complication in surgical patients. The purpose of this study was to describe the incidence and impact on outcomes of Clostridioides difficile infection in adult patients after appendectomy. Methods The American College of Surgeons National Surgical Quality Improvement Program data set was used to identify all patients with the primary procedure code of appendectomy between 2016 and 2018. Patient demographics and clinical characteristics were extracted from the database, and descriptive statistics were performed. A multivariate logistic regression was created to identify predictors of Clostridioides difficile infection following appendectomy. Results A total of 135,272 patients who underwent appendectomy were identified, and of those, 469(0.35%) developed Clostridioides difficile infection. Patients with Clostridioides difficile infection were more likely to be older (51.23 vs 40.47 years; P < .0001), female (P = .004), American Society of Anesthesiology score >2 (P < .0001), present with septic shock (P < .0001), or lack functional independence (P < .0001). Patients with Clostridioides difficile infection were more likely to have increased operative time (62.9 vs 50.4 minutes; P < .0001), have perforated appendicitis (48.9% vs 23.5%; P < .0001), and underwent open surgery (7.0% vs 4.0%; P = .0006). Postoperatively, patients with Clostridioides difficile infection required a longer length of stay (4.8 vs 1.8 days; P < .0001), had increased mortality (2.1% vs 0.1%; P < .0001), higher incidences of postoperative abscess (14.9% vs 2.9%; P < .0001), postoperative sepsis (15.1% vs 4.0%; P < .0001), and readmission (30.7% vs 3.4%; all P < .0001). On multivariate analysis, older age (P < .0001), female sex (P = .0043), septic shock (P = .0002), open surgery (P = .037), and dirty wound class (P = .0147) were all independently predictive factors of Clostridioides difficile infection after appendectomy. Conclusion Clostridioides difficile infection is an uncommon postoperative complication of appendectomy and is associated with worse outcomes and higher mortality. Older patients, female sex, those with sepsis, and those undergoing open surgery are at higher risk for developing Clostridioides difficile infection.
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Clostridioides difficile is a Gram-positive, spore-forming obligate anaerobe and a major threat to the healthcare system world-wide. Because of its strict anaerobic requirements, the infectious and transmissible morphotype is the dormant spore. During infection, C. difficile produces spores that can persist in the host and are responsible for disease recurrence and transmission, especially between hospitalized patients. Although the C. difficile spore surface mediates critical interactions with host surfaces, this outermost layer, known as the exosporium, is poorly conserved when compared to members of the Bacillus genus. Notably, the exosporium has been shown to be important for the persistence of C. difficile in the host. In this review, the ultrastructural properties, composition, and morphogenesis of the exosporium will be discussed.
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Clostridioides difficile is an important nosocomial pathogen that causes severe diarrhea by producing toxins and transmits disease by producing spores. While both processes are crucial for C. difficile disease, only a subset of cells express toxins and/or undergo sporulation.
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Antibiotics are modifiable risk factors for Clostridioides difficile infection (CDI), driving pathogenesis via gut microbiome disruption. The management of patients with CDI prescribed concomitant non-CDI antibiotics is problematic and influences CDI outcome and recurrence risk. Though an assessment of the ongoing requirement for concomitant antibiotics is essential, discontinuation is often not possible. Antibiotics for other reasons might also need to be commenced during CDI therapy. Attempts to minimise the number and duration of antibiotics with a change to a low-risk class are recommended. Fidaxomicin might be preferable to vancomycin due to it having less effect on the gut microbiome; however, vancomycin is also acceptable. Metronidazole should be avoided and proton pump inhibitors discontinued. Access to fidaxomicin might be limited; hence, it should be prioritised for patients at high risk of recurrence. There is insufficient evidence to support extending anti-CDI therapy duration and concerns regarding microbiome effect remain. The addition of bezlotoxumab might be considered if multiple additional risk factors for recurrent CDI exist, though the amount of evidence is low. Investigational approaches to reduce the effect of concomitant antibiotics on the gut microbiome could further optimise CDI treatment in the presence of concomitant antibiotic use in the future.
Chapter
The most common world-wide cause of antibiotic-associated infectious diarrhea and colitis is the toxin producing bacterium, Clostridioides difficile (C. difficile). Here we review the background and characteristics of the bacterium and the toxins produced together with the epidemiology and the complex pathogenesis that leads to a broad clinical spectrum of disease. The review describes the difficulties faced in obtaining a quick and accurate diagnosis despite the range of sensitive and specific diagnostic tools available. We also discuss the problem of disease recurrence and the importance of disease prevention. The high rates of infection recurrence mean that treatment strategies are constantly under review and we outline the diverse treatment options that are currently in use and explore the emerging treatment options of pulsed antibiotic use, microbial replacement therapies and the use of monoclonal antibodies. We summarize the future direction of treatment strategies which include the development of novel antibiotics, the administration of oral polyclonal antibody formulations, the use of vaccines, the administration of competitive non-toxigenic spores and the neutralization of antibiotics at the microbiota level. Future successful treatments will likely involve a combination of therapies to provide the most effective and robust approach to C. difficile management.
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Background Clostridioides (Clostridium) difficile commonly causes hospital-acquired infection which can range from mild diarrhoea to life-threatening toxic megacolon and even death. Reports on C. difficile infection (CDI) in Vietnam are limited, so this study was designed to evaluate the prevalence, molecular epidemiology and antimicrobial susceptibility of C. difficile isolated from children with diarrhoea in Vietnam. Infants are often colonised with C. difficile and it was hypothesised that those colonising strains would represent strains of C. difficile circulating in the hospital/region at the time, however, this was not an attempt to determine if C. difficile was the cause of the diarrhoea. Methods Diarrhoeal stool samples collected at two children's hospitals in northern Vietnam from 1st October 2020 to 28th February 2021 were transported to Perth, Western Australia, for culture of C. difficile and further investigations on isolates; PCR ribotyping, toxin gene profiling and antimicrobial susceptibility testing. Results From these hospitals, 370 diarrhoeal stool samples were collected, most from children aged 1–15 months (71.9%; 266/370). The overall prevalence of C. difficile in stool samples from children aged ≤16 years was 37.8% (140/370) and the highest prevalence was in the 2–12 months age group (52.9%; 74/140). In total, 151 isolates of C. difficile were recovered; the proportion of toxigenic isolates was 16.6% (25/151). Of the 25 toxigenic C. difficile isolates, the toxin gene profiles A⁺B⁺CDT⁻ and A⁻B⁺CDT⁻ comprised 72% and 28%, respectively. The four most prevalent C. difficile ribotypes (RTs) were QX 011 (25/151), RT 010 (25/151), QX 107 (12/151) and RT 012 (11/151). All isolates were susceptible to vancomycin, metronidazole and fidaxomicin, while there was significant resistance to clindamycin (90.1%), and some to moxifloxacin (6.6%) and rifaximin (3.3%). Conclusion The prevalence of C. difficile in children with diarrhoea was high (37.8%) although the proportion of toxigenic strains was comparatively low. The clinical significance of any isolate needs to be determined. https://authors.elsevier.com/c/1eonI3qfpmWqy1
Article
Clostridioides difficile infection is a global health threat and remains the primary cause of hospital-acquired infections worldwide. The burgeoning incidence and severity of infections coupled with high rates of recurrence have created an urgent need for novel therapeutics. Here, we report a novel natural product scaffold as a potential anticlostridial lead with antivirulence properties and potent activity both in vitro and in vivo . A whole cell phenotypic screening of 1,000 purified natural products identified 6 compounds with potent activity against C . difficile (minimum inhibitory concentration (MIC) range from 0.03 to 2 μg/ml). All these 6 compounds were non-toxic to human colorectal cells. The natural product compounds also inhibited the production of key toxins, TcdA and TcdB, the key virulence determinants of C . difficile infection pathology. Additionally, the compounds exhibited rapid bactericidal activity and were superior to the standard-of-care antibiotic vancomycin, in reducing a high inoculum of C . difficile in vitro . Furthermore, a murine model of C . difficile infection revealed that compound NP-003875 conferred 100% protection to the infected mice from clinical manifestations of the disease. Collectively, the current study lays the foundation for further investigation of the natural product NP-003875 as a potential therapeutic choice for C . difficile infection.
Article
Background Fidaxomicin (FDX) has received considerable attention as a novel therapeutic alternative agent to vancomycin (VCM) for Clostridioides difficile infection (CDI). However, the superiority and efficacy profile of FDX are not sufficiently determined by high-quality evidence. This study aimed to clarify the superiority of FDX for CDI treatment through a systematic review and meta-analysis. Methods We conducted a meta-analysis of randomized controlled trials (RCTs) which evaluated the efficacy and safety of FDX and VCM in patients with CDI. Electronic databases (PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov) were searched for studies published until October 15, 2021. The primary endpoint was global cure. The secondary endpoints were clinical cure, recurrence, and adverse event. Risk ratios (RRs), risk differences (RDs), and 95% confidence intervals were calculated using Mantel-Haenszel random-effects model. The risk of bias was assessed using Cochrane Handbook for Systematic Reviews of Interventions and Assessment Criteria. Results Six RCTs were included in this meta-analysis. Compared to VCM, FDX was associated with significantly higher global cure rates (RR = 1.18, P < 0.00001; RD = 0.11, 95% CI = 0.07–0.16). In addition, clinical cure rates were comparable between FDX and VCM (P = 0.31). FDX was associated with significantly lower recurrence rates compared to VCM (RR = 0.59, P < 0.0001). In addition, adverse event rates were not significantly different between the drugs (P = 0.41). Conclusion FDX achieves significantly higher global cure rates and lower recurrence rates and is comparable to VCM in clinical cure rates and adverse event rates in patients with CDI. Collectively, FDX is superior to VCM as a therapeutic agent for CDI.
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At our institution, the prevalence of clinical isolates of Clostridium difficile with resistance to metronidazole is 6.3%. We observed that initial metronidazole MICs of 16 to 64 mg/liter against toxigenic, primary fresh C. difficile isolates, as determined by agar dilution, decreased to 0.125 mg/liter after the isolates were thawed. In this study, we examined the possibility of heterogeneous or inducible resistance. Totals of 14 metronidazole-resistant and 10 metronidazole-susceptible clinical isolates of toxigenic C. difficile were studied. The isolates were investigated for the presence of nim genes by PCR. After the isolates were thawed, susceptibility testing was done by agar dilution, by disc diffusion using a 5-μg metronidazole disc, and by the Etest method. An experiment for determining the effect of prolonged exposure to metronidazole was applied to all resistant isolates and to susceptible control strains. None of the isolates presented the nim genes. All initially metronidazole-resistant C. difficile isolates became susceptible after thawing; however, they presented slow-growing subpopulations within the inhibition zones of both the disk and the Etest strip. All metronidazole-susceptible isolates remained homogeneously susceptible by both methods. After prolonged exposure in vitro to metronidazole, no zone of inhibition was found around the 5-μg disk in any of the metronidazole-resistant isolates, and the MICs as determined by the Etest method ranged from 0.125 to >256 mg/liter, with colonies growing inside the inhibition zone. Our results indicate that (i) resistance to metronidazole was not due to the presence of nim genes, (ii) resistance to metronidazole in toxigenic C. difficile isolates is heterogeneous, and (iii) prolonged exposure to metronidazole can select for in vitro resistance. We recommend routine performance of the disk diffusion method (5-μg metronidazole disk) with primary fresh C. difficile isolates in order to ensure that metronidazole-heteroresistant populations do not go undetected.
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To determine the presence of Clostridium difficile, we sampled cooked and uncooked meat products sold in Tucson, Arizona. Forty-two percent contained toxigenic C. difficile strains (either ribotype 078/toxinotype V [73%] or 027/toxinotype III [NAP1 or NAP1-related; 27%]). These findings indicate that food products may play a role in interspecies C. difficile transmission.
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Vancomycin and metronidazole remain the only primary options for the treatment of Clostridium difficile infection (CDI). Recent reports have suggested a superior clinical response to vancomycin therapy compared with metronidazole, but this has been difficult to prove or explain. There are few robust in vitro data of the effects of antibiotic treatment of CDI in a gut reflective setting. We used clindamycin to induce high-level toxin production by two epidemic C. difficile PCR ribotypes in a human gut model of CDI. Vancomycin was instilled into the models to achieve in vivo faecal concentrations. C. difficile populations and toxin titres, and gut bacterial populations and vancomycin levels were monitored before, during and after vancomycin instillation. Clindamycin treatment elicited C. difficile germination and high-level cytotoxin production. Vancomycin reduced total viable counts and cytotoxin titres of both C. difficile PCR ribotypes, with no evidence of recurrence before the model runs were ended. C. difficile PCR ribotype 027 populations exhibited greater germination capacity than did PCR ribotype 106. Vancomycin was more rapidly effective against the greater numbers of PCR ribotype 027 vegetative forms. Vancomycin showed no activity against C. difficile spores. Bacteriological response to vancomycin varies between strains causing CDI, possibly correlating with the extent of germination capacity. Vancomycin effectively reduced vegetative forms and cytotoxin titres of both of the epidemic C. difficile PCR ribotypes evaluated, but showed no anti-spore activity. Comparison with the results of a previous gut model study showed that vancomycin was more effective than metronidazole in reducing C. difficile PCR ribotype 027 numbers and cytotoxin titres.
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In recent years, Clostridium difficile infection (CDI) has emerged as an increasing problem, both in in- and outpatients. In a rural region of southern Germany, the annual number of C. difficile toxin (Tcd)-positive patients has increased from 95 to 796 in the period from 2000 to 2007. Simultaneously, the proportion of positive tests among all Tcd examinations has risen from 7.0% to 12.8%, indicating that the higher number of affected patients was not solely due to an increase in the number of assays. Elevated numbers of CDI have recently been associated with outbreaks of the ribotype 027 strain, particularly in North America. This strain has also been isolated in Europe, including in Germany. Ribotyping and PCR testing for binary toxin genes of C. difficile strains isolated from in- and outpatients demonstrate a predominance (59%) of C. difficile ribotype 001, which exhibits antibiotic resistance to erythromycin, ciprofloxacin, and moxifloxacin, but lacks binary toxin genes. In summary, in our region of Germany, the number of patients affected by CDI has increased, probably due to spread of C. difficile ribotype 001.
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The human intestinal microbiota is essential to the health of the host and plays a role in nutrition, development, metabolism, pathogen resistance, and regulation of immune responses. Antibiotics may disrupt these coevolved interactions, leading to acute or chronic disease in some individuals. Our understanding of antibiotic-associated disturbance of the microbiota has been limited by the poor sensitivity, inadequate resolution, and significant cost of current research methods. The use of pyrosequencing technology to generate large numbers of 16S rDNA sequence tags circumvents these limitations and has been shown to reveal previously unexplored aspects of the "rare biosphere." We investigated the distal gut bacterial communities of three healthy humans before and after treatment with ciprofloxacin, obtaining more than 7,000 full-length rRNA sequences and over 900,000 pyrosequencing reads from two hypervariable regions of the rRNA gene. A companion paper in PLoS Genetics (see Huse et al., doi: 10.1371/journal.pgen.1000255) shows that the taxonomic information obtained with these methods is concordant. Pyrosequencing of the V6 and V3 variable regions identified 3,300-5,700 taxa that collectively accounted for over 99% of the variable region sequence tags that could be obtained from these samples. Ciprofloxacin treatment influenced the abundance of about a third of the bacterial taxa in the gut, decreasing the taxonomic richness, diversity, and evenness of the community. However, the magnitude of this effect varied among individuals, and some taxa showed interindividual variation in the response to ciprofloxacin. While differences of community composition between individuals were the largest source of variability between samples, we found that two unrelated individuals shared a surprising degree of community similarity. In all three individuals, the taxonomic composition of the community closely resembled its pretreatment state by 4 weeks after the end of treatment, but several taxa failed to recover within 6 months. These pervasive effects of ciprofloxacin on community composition contrast with the reports by participants of normal intestinal function and with prior assumptions of only modest effects of ciprofloxacin on the intestinal microbiota. These observations support the hypothesis of functional redundancy in the human gut microbiota. The rapid return to the pretreatment community composition is indicative of factors promoting community resilience, the nature of which deserves future investigation.
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Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease. We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk. Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2). Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.
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To compare the efficacy of oritavancin and vancomycin in the treatment of Clostridium difficile infection (CDI) using an in vitro human gut model. We induced CDI by instilling clindamycin into an in vitro gut model primed with pooled human faeces and C. difficile ribotype 027 spores. Oritavancin and vancomycin were instilled in separate experiments at levels equivalent to those expected in the faeces (vancomycin) of patients or levels limited by the solubility of the drug (oritavancin). Clindamycin exposure elicited C. difficile proliferation and high-level cytotoxin production in both experiments. Vancomycin instillation reduced vegetative C. difficile numbers within 1 day but did not affect the numbers of C. difficile spores. Oritavancin instillation markedly reduced C. difficile vegetative numbers and spores to below the limits of detection within 2 days. Cytotoxin titres in both experiments declined to the limits of detection after instillation with oritavancin or vancomycin, but did so more quickly (within 5 days) in the vancomycin experiment. Cessation of vancomycin instillation was associated with further C. difficile proliferation and high-level cytotoxin production. Conversely, toxin recrudescence was not observed following cessation of oritavancin. Both oritavancin and vancomycin were effective in treating clindamycin-induced CDI in a human gut model, but only oritavancin appeared active against spore forms of C. difficile. Furthermore, recurrence of high-level cytotoxin production was observed following vancomycin instillation but not oritavancin. Oritavancin therapy may be more effective in treating CDI than vancomycin, possibly because it may prevent recrudescence of C. difficile spores.
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Outbreaks of Clostridium difficile infections (CDI) with increased severity, high relapse rate and significant mortality have been related to the emergence of a new, hypervirulent C. difficile strain in North America and Europe. This emerging strain is referred to as PCR ribotype 027 (Type 027). Since 2005, individual countries have developed surveillance studies about the spread of type 027.C. difficile Type 027 has been reported in 16 European countries. It has been responsible for outbreaks in Belgium, Germany, Finland, France, Ireland, Luxembourg, The Netherlands, Switzerland and the United Kingdom (England, Wales, Northern Ireland and Scotland). It has also been detected in Austria, Denmark, Sweden, Norway, Hungary, Poland and Spain. Three countries experienced imported patients with CDI due to Type 027 who acquired the infection abroad.The antimicrobial resistance pattern is changing, and outbreaks due to clindamycin-resistant ermB positive Type 027 strains have occurred in three European countries. Ongoing epidemiological surveillance of cases of CDI, with periodic characterisation of the strains involved, is required to detect clustering of cases in time and space and to monitor the emergence of new, highly virulent clones.
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The incidence of Clostridium difficile infection is increasing, with reports implicating fluoroquinolone use. A three-stage chemostat gut model was used to study the effects of three fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin) on the gut microbiota and two epidemic C. difficile strains, strains of PCR ribotypes 027 and 001, in separate experiments. C. difficile total viable counts, spore counts, and cytotoxin titers were determined. The emergence of C. difficile isolates with reduced antibiotic susceptibility was monitored with fluoroquinolone-containing medium, and molecular analysis of the quinolone resistance-determining region was performed. C. difficile spores were quiescent in the absence of fluoroquinolones. Instillation of each fluoroquinolone led to C. difficile spore germination and high-level cytotoxin production. High-level toxin production occurred after detectable spore germination in all experiments except those with C. difficile PCR ribotype 027 and moxifloxacin, in which marked cytotoxin production preceded detectable germination, which coincided with isolate recovery on fluoroquinolone-containing medium. Three C. difficile PCR ribotype 027 isolates and one C. difficile PCR ribotype 001 isolate from fluoroquinolone-containing medium exhibited elevated MICs (80 to ≥180 mg/liter) and possessed mutations in gyrA or gyrB. These in vitro results suggest that all fluoroquinolones have the propensity to induce C. difficile infection, regardless of their antianaerobe activities. Resistant mutants were seen only following moxifloxacin exposure.
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Antimicrobial treatment for Clostridium difficile infection (CDI) has typically been metronidazole, although reports have questioned the efficacy of this option. We screened recently isolated C. difficile (2005-06) for susceptibility to metronidazole and compared results for historic isolates (1995-2001). C. difficile ribotypes 001 (n = 86), 106 (n = 81) and 027 (n = 48) and isolates from the 10 other most prevalent ribotypes in Leeds (n = 57) were screened using spiral gradient endpoint analysis (SGE). C. difficile with metronidazole SGE MICs > or = 6 mg/L were analysed further by agar incorporation and Etest. Multiple-locus variable-number tandem-repeat analysis (MLVA) typing was performed for 28 C. difficile isolates. No reduced metronidazole susceptibility was observed in C. difficile ribotypes 106 and 027 (geometric mean SGE MICs 1.11 and 0.90 mg/L, respectively). In contrast, 21 (24.4%) C. difficile ribotype 001 demonstrated reduced susceptibility to metronidazole (geometric mean SGE MICs 3.51 mg/L, P < 0.001). Variations in susceptibility were observed relating to the method and media, but increased metronidazole MICs were confirmed by an agar incorporation method. Geometric mean agar incorporation MICs for historic C. difficile ribotype 001 (n = 72) were 1.03 (range 0.25-2) mg/L compared with 5.94 (4-8) mg/L (P < 0.001) for recent isolates displaying reduced metronidazole susceptibility. MLVA typing revealed two clonal complexes of C. difficile with reduced susceptibility to metronidazole. We have demonstrated the emergence of reduced susceptibility to metronidazole in 24.4% of the recent C. difficile ribotype 001 isolates from our institution. Our observations could have implications in the clinical setting due to the poor penetration of metronidazole into the colon.
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Relapse of Clostridium difficile-associated diarrhoea occurs in 15-20% of patients; however, whether relapse is due to an endogenous source of the organism or reinfection from the environment remains unclear. Restriction enzyme analysis (REA) of chromosomal DNA was used to type multiple isolates from ten patients who had experienced apparent relapses. More than half the relapses were due to infection with a new strain of C. difficile. The remaining patients were infected with the same strain, but whether this strain was acquired from the environment or from endogenous sources could not be determined. Relapses with a different strain of C. difficile could occur if an individual harboured more than one strain in their gastrointestinal tract. To investigate this possibility ten other patients were assessed for carriage of multiple strains. Ten colonies from a primary culture plate from each patient were typed by REA and tested for their ability to produce cytotoxin. All isolates from the same patient were identical by both methods, indicating that multiple carriage of strains may be a rare event.
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We studied the acquisition and transmission of Clostridium difficile infection prospectively on a general medical ward by serially culturing rectal-swab specimens from 428 patients admitted over an 11-month period. Immunoblot typing was used to differentiate individual strains of C. difficile. Seven percent of the patients (29) had positive cultures at admission. Eighty-three (21 percent) of the 399 patients with negative cultures acquired C. difficile during their hospitalizations. Of these patients, 52 (63 percent) remained asymptomatic and 31 (37 percent) had diarrhea; none had colitis. Patient-to-patient transmission of C. difficile was evidenced by time-space clustering of incident cases with identical immunoblot types and by significantly more frequent and earlier acquisition of C. difficile among patients exposed to roommates with positive cultures. Of the hospital personnel caring for patients with positive cultures, 59 percent (20) had positive cultures for C. difficile from their hands. The hospital rooms occupied by symptomatic patients (49 percent) as well as those occupied by asymptomatic patients (29 percent) were frequently contaminated. Eighty-two percent of the infected cohort still had positive cultures at hospital discharge, and such patients were significantly more likely to be discharged to a long-term care facility. We conclude that nosocomial C. difficile infection, which was associated with diarrhea in about one third of cases, is frequently transmitted among hospitalized patients and that the organism is often present on the hands of hospital personnel caring for such patients. Effective preventive measures are needed to reduce nosocomial acquisition of C. difficile.
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Toxin A but not toxin B, appears to mediate intestinal damage in animal models of Clostridium difficile enteritis. The purpose of this study was to investigate the electrophysiologic and morphologic effects of purified C. difficile toxins A and B on human colonic mucosa in Ussing chambers. Luminal exposure of tissues to 16-65 nM of toxin A and 0.2-29 nM of toxin B for 5 h caused dose-dependent epithelial damage. Potential difference, short-circuit current and resistance decreased by 76, 58, and 46%, respectively, with 32 nM of toxin A and by 76, 55, and 47%, respectively, with 3 nM of toxin B, when compared with baseline (P < 0.05). 3 nM of toxin A did not cause electrophysiologic changes. Permeability to [3H]mannitol increased 16-fold after exposure to 32 nM of toxin A and to 3 nM of toxin B when compared with controls (P < 0.05). Light and scanning electron microscopy after exposure to either toxin revealed patchy damage and exfoliation of superficial epithelial cells, while crypt epithelium remained intact. Fluorescent microscopy of phalloidin-stained sections showed that both toxins caused disruption and condensation of cellular F-actin. Our results demonstrate that the human colon is approximately 10 times more sensitive to the damaging effects of toxin B than toxin A, suggesting that toxin B may be more important than toxin A in the pathogenesis of C. difficile colitis in man.
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We analyzed the Spanish hospital discharges registered from 1997 to 2005 with patient diagnoses of "intestinal infection due to Clostridium difficile." The mean annual incidence rate was 41.2 diagnoses per 100,000 discharges. A significant increase was found from 1997 to 2005 (slope of the regression line [b], 5.12; P < .001). Overall rates were 2.5 times as high in the group of patients aged at least 65 years as in the group aged 45-64 years. © 2008 by The Society for Healthcare Epidemiology of America. All rights reserved.
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Despite recognition that Clostridium difficile diarrhea/colitis is a nosocomial infection, the manner in which this organism is transmitted is still not clear. Hands of health care workers have been shown to be contaminated with C. difficile and suggested as a vehicle of transmission. Therefore, we conducted a controlled trial of the use of disposable vinyl gloves by hospital personnel for all body substance contact (prior to the institution of universal body substance precautions) to study its effect on the incidence of C. difficile disease. The incidence of nosocomial C. difficile diarrhea was monitored by active surveillance for six months before and after an intensive education program regarding glove use on two hospital wards. The interventions included initial and periodic in-services, posters, and placement of boxes of gloves at every patient's bedside. Two comparable wards where no special intervention was instituted served as controls. A decrease in the incidence of C. difficile diarrhea from 7.7 cases/1,000 patient discharges during the six months before intervention to 1.5/1,000 during the six months of intervention on the glove wards was observed (p = 0.015). No significant change in incidence was observed on the two control wards during the same period (5.7/1,000 versus 4.2/1,000). Point prevalence of asymptomatic C. difficile carriage was also reduced significantly on the glove wards but not on the control wards after the intervention period (glove wards, 10 of 37 to four of 43, p = 0.029; control wards, five of 30 to five of 49, p = 0.19). The cost of 61,500 gloves (4,505 gloves/100 patients) used was $2,768 on the glove wards, compared with $1,895 (42,100 gloves; 3,532 gloves/100 patients) on the control wards. Vinyl glove use was associated with a reduced incidence of C. difficile diarrhea and is indirect evidence for hand carriage as a means of nosocomial C. difficile spread.