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Distribution of Serogroups of Vibrio cholerae non-O1 non-O139 with Specific Reference to Their Ability to Produce Cholera Toxin, and Addition of Novel Serogroups
Abstract
A total of 1898 strains of Vibrio cholerae non-O1 non-O139, which had been collected worldwide for the past 3 year period of 1994-1996, were serogrouped. The strains were also examined for presence of cholera toxin (CT) gene (ctx) and NAG-ST gene, and strains which carried to ctx were further analyzed for their ability to produce CT. In addition, attempts were made to establish novel serogroups for those serologically untypable strains. Of those examined, 1,774 strains of V. cholerae non-O1 non-O139 was classified into 128 known serogroups while 50 strains were found to belong to R type, and the rest of the 74 strains could not be serotyped. Distribution of the serogroups did not seem to correspond to either the strains geographic distribution or sources of isolation. Of those serologically untypable strains, 38 novel serogroups (O156-O193) were established and added to our reference of V. cholerae antigenic schema. It was also found that antisera raised against many V. cholerae strains included R antibodies. This indicates that any V. cholerae antisera for diagnostic purpose should be absorbed with the reference R strains, CA385, before use. There were luminescence producing strains among those sucrose and VP reaction negative strains. Subsequent DNA/DNA homology analysis revealed that they were identified as V. cholerae. This points to a possibility that strains tentatively identified as Vibrio mimicus by conventional biochemical tests may have included luminescent strains of V. cholerae. It is thus highly recommended that strains in question should be tested for the luminescence production in order to differentiate V. cholerae from V. mimicus. Of those 1989 strains examined, 37 strains (ca. 2%) were found to produce CT. Interestingly, CT producing strains were prevalent in serogroup O141; 10 strains out of 16 strains (63%) were positive for CT. The evidence calls for a caution to possible occurrence of cholera-like diarrhea caused by V. cholerae O141 in the future.
... The theme that V. cholerae serogrouping as O37 can be both members of the same lineage as well as being unrelated to that lineage(s) was subsequently reiterated [25]. In this study, electrophoretic typing (ET) by multi-locus enzyme electrophoresis (MLEE) rather than molecular fingerprinting was used to classify 254 isolates from Mexico and Guatemala, plus 143 of the V. cholerae serogrouping reference strains [38], into 279 electrophoretic types. The authors noted that 'there are two examples of epidemic V. cholerae expressing a non-O1 antigen' [25], referring to V. cholerae O139 and the Sudanese outbreak of V. cholerae O37 [25]. ...
... Beltrán et al. also found that the O37 reference isolate was of the same ET as the non-toxigenic serogroup O102 reference isolate, obtained from PR China in 1988 [38]. However, the authors acknowledged that sequence data would be required in addition to MLEE data to understand the clonal relationships of V. cholerae, and to account for the possible role of recombination amongst these bacteria [39]. ...
... To our knowledge, V. cholerae have not yet been identified that harbour ctxB9 other than Sudan lineage V. cholerae O37 [9,58]. Although it might be tempting to use ctxB9 as a marker of V. cholerae O37, it is important to recall that not all V. cholerae O37 are toxigenic [25,38], and that because ctxB is encoded by a mobilizable prophage, we cannot exclude the possibility that this gene is present in other V. cholerae just because we have only found ctxB9 in members of this lineage to date. ...
Between 1965 and 1968, outbreaks of cholera in Sudan and former Czechoslovakia provoked considerable public health concern. These still represent important historical events that need to be linked to the growing genomic evidence describing the aetiological agent of cholera, Vibrio cholerae. Whilst O1 serogroup V. cholerae are canonically associated with epidemic and pandemic cholera, these events were caused by a clone of toxigenic V. cholerae O37 that may be more globally distributed than just to Europe and North Africa. Understanding the biology of these non-O1 strains of V. cholerae is key to understanding how diseases like cholera continue to be globally important. In this article, we consolidate epidemiological, molecular and genomic descriptions of the bacteria responsible for these outbreaks. We attempt to resolve discrepancies in order to summarize the history and provenance of as many commonly used serogroup O37 strains as possible. Finally, we highlight the potential for whole-genome sequencing of V. cholerae O37 isolates from strain collections to shed light on the open questions that we identify.
... Vibrio cholerae is a Gram-negative, flagellated bacterium with a comma shape. Based on somatic O antigen, more than 206 serotypes of V. cholerae have already been discovered, with V. cholerae O1 and O139 being the epidemic serogroups (Yamai et al., 1997). Ogawa and Inaba are the two primary serotypes of V. cholerae O1. ...
... Natural sources were used to develop several antimicrobials. In developing nations, healthcare has benefited from low-cost, sometimes soil-derived medicines, but exhausting their viability necessitates discovery of alternative antibacterial compounds (Gould, 2016;Woon and Fisher, 2016; 4.6 Development of new antimicrobial agents Wohlleben et al., 2016;Clardy et al., 2009;Mir et al., 2020). However, the generation of synthetic antimicrobials from existing natural medications has been shown to have low success rates (Woon and Fisher, 2016;Payne et al., 2007). ...
... In developing nations, healthcare has benefited from low-cost, sometimes soil-derived medicines, but exhausting their viability necessitates discovery of alternative antibacterial compounds (Gould, 2016;Woon and Fisher, 2016; 4.6 Development of new antimicrobial agents Wohlleben et al., 2016;Clardy et al., 2009;Mir et al., 2020). However, the generation of synthetic antimicrobials from existing natural medications has been shown to have low success rates (Woon and Fisher, 2016;Payne et al., 2007). The researchers are now concentrating their efforts on finding novel ways to combat MDR. ...
... Vibrio cholerae is a Gram-negative, flagellated bacterium with a comma shape. Based on somatic O antigen, more than 206 serotypes of V. cholerae have already been discovered, with V. cholerae O1 and O139 being the epidemic serogroups (Yamai et al., 1997). Ogawa and Inaba are the two primary serotypes of V. cholerae O1. ...
... Natural sources were used to develop several antimicrobials. In developing nations, healthcare has benefited from low-cost, sometimes soil-derived medicines, but exhausting their viability necessitates discovery of alternative antibacterial compounds (Gould, 2016;Woon and Fisher, 2016; 4.6 Development of new antimicrobial agents Wohlleben et al., 2016;Clardy et al., 2009;Mir et al., 2020). However, the generation of synthetic antimicrobials from existing natural medications has been shown to have low success rates (Woon and Fisher, 2016;Payne et al., 2007). ...
... In developing nations, healthcare has benefited from low-cost, sometimes soil-derived medicines, but exhausting their viability necessitates discovery of alternative antibacterial compounds (Gould, 2016;Woon and Fisher, 2016; 4.6 Development of new antimicrobial agents Wohlleben et al., 2016;Clardy et al., 2009;Mir et al., 2020). However, the generation of synthetic antimicrobials from existing natural medications has been shown to have low success rates (Woon and Fisher, 2016;Payne et al., 2007). The researchers are now concentrating their efforts on finding novel ways to combat MDR. ...
ABSTRACT: Bacteria are cosmopolitan in nature and are present even inside Human gut, lungs and on skin surfaces. Most of the bacteria are beneficial but some strains are pathogenic and some of them are zoonotic. Bacterial infection could range in severity from latent infection to active infection depending on their pathogenicity and are affecting millions of individuals worldwide (Mir, 2013). The common examples of pathogenic bacteria include S. epidermis, straphylococcus, bacteriodes and enterobacteriaceae. Some bacterial infections acted as the significant public health threat worldwide. Salmonllosis caused by the salmonella enteric subspecies enterica serovar Typhimurium accounts for about 93.8 million cases annually and are associated with death toll up to 150,000 every year. Salmonella Typhimurium has been identified as the most common serovar causing non-typhoidal salmonella infection which accounts about 63.7 % in children less than 5 years of age worldwide. Besides salmonellosis, tuberculosis and Cholera are also the life threatening food-borne bacterial infections globally. The major concern in the present times is resistance developed by the pathogenic bacteria against the antibiotics to withstand the adverse effects of drugs, resulting in their efficiency of virulence. The major classes of drugs commonly used for bacterial infections include penicillin, tetracycline, cephalosporins, fluroquinolones, Macrolides and sulfonamides. In this chapter we will discuss some major bacterial infections, their nature, novel antibacterial targets and present approach of therapeutics to combat their infection.
... There was no difference in the illness caused by the two serogroups due to the same virulence, mainly cholera toxin (CT) and similar encoding genes [4][5][6]. In recent years, the cholera toxin (CT)-producing or cholera toxin gene (ctx)-positive strains of V. cholerae non-O1/non-O139 serogroups have been extensively reported [7][8][9], as their pathogenicity and potential harm are worthy of attention. Diagnostic serums are often used to rapidly identify V. cholerae strains; however, it is sometimes difficult to distinguish them easily using the serum agglutination test alone, especially between the serotypes in the O1 serogroup. ...
... The former, usually an epidemic strain, is of great significance in the cholera epidemic while the latter, as a non-epidemic strain, is often found in localized diarrhea and environmental water [6,15]. It was noteworthy that the CT-producing and ctx-positive strains of the V. cholerae non-O1/non-O139 serogroups have been increasingly reported [7][8][9] and have also been found in Jiaxing, a water city threatened by cholera in the south of the Yangtze River, China. Therefore, our new developed multiplex assay can not only be used in the emergency detection of V. cholerae during an epidemic period but may also play an important role in routine surveillance during non-epidemic periods. ...
Molecular diagnostic assays for cholera detection have superior sensitivity to conventional assays and are now being accepted as the new standard method, especially the real-time PCR/RT-PCR. However, limited throughput capacity and long detection duration prevent them from detecting more specimens and more targets in one turnaround time simultaneously. In this study, we utilized nucleic acid extraction-free, direct RT-PCR and high-speed amplification to develop a novel multiplex assay, a quadplex direct one-tube real-time RT-PCR assay, for rapid detection of the serogroup and cholera toxin toxigenicity of Vibrio cholerae targeting the epsM, ctxA, rfb-O1, and rfb-O139 genes. Performance of the multiplex assay was evaluated by comparison with the monoplex real-time PCR assay according to the China Cholera Prevention Manual. Detection data from clinical specimens showed that the new assay had good diagnostic sensitivities for epsM (100%, n = 301), ctxA (100%, n = 125), rfb-O1 (100%, n = 85), and rfb-O139 (97.87%, n = 49). Analysis of the analytical sensitivities with serial dilutions of positive standards showed that the detection limits of the new assay for Vibrio cholerae epsM, ctxA, rfb-O1, and rfb-O139 were up to 200, 590, 115, and 1052 copies per mL lower than the monoplex real-time PCR (910, 345, and 1616 copies/mL respectively, for ctxA, rfb-O1, and rfb-O139). The results indicate that the multiplex assay is a rapid, sensitive, specific, and easy-to-use detection tool for Vibrio cholerae, especially suitable for rapid identification and screening detection of mass specimens.
... This bacterium inhabits aquatic environments and can cause cholera outbreaks in endemic areas and regions affected by natural or man-made disasters. V. cholerae is broadly classified into >200 serogroups based on the lipopolysaccharide (LPS) component (O antigen) of the cell wall, and out of these, only O1 and O139 are known to cause epidemics and pandemics 1 . In contrast, the non-O1/O139 V. cholerae, which also reside in the environment, generally cause sporadic diseases with mild 'cholera-like diarrhea' and food-associated outbreaks [2][3][4][5] . ...
... The convergence of each run was manually evaluated by inspecting the chain traces. The tree data obtained from BEAST was summarized using the program TreeAnnotator v. 1 Springer Nature journal content, brought to you courtesy of Springer Nature Customer Service Center GmbH ("Springer Nature"). Springer Nature supports a reasonable amount of sharing of research papers by authors, subscribers and authorised users ("Users"), for smallscale personal, non-commercial use provided that all copyright, trade and service marks and other proprietary notices are maintained. ...
Cholera is a life-threatening infectious disease that remains an important public health issue in several low and middle-income countries. In 1992, a newly identified O139 Vibrio cholerae temporarily displaced the O1 serogroup. No study has been able to answer why the potential eighth cholera pandemic (8CP) causing V. cholerae O139 emerged so successfully and then died out. We conducted a genomic study, including 330 O139 isolates, covering emergence of the serogroup in 1992 through to 2015. We noted two key genomic evolutionary changes that may have been responsible for the disappearance of genetically distinct but temporally overlapping waves (A-C) of O139. Firstly, as the waves progressed, a switch from a homogenous toxin genotype in wave-A to heterogeneous genotypes. Secondly, a gradual loss of antimicrobial resistance (AMR) with the progression of waves. We hypothesize that these two changes contributed to the eventual epidemiological decline of O139. The O139 Vibrio cholerae serogroup emerged in the 1990s and spread rapidly but did not become globally dominant. Here, the authors describe the genomic epidemiology of this strain and identify changes in virulence and antimicrobial resistance characteristics that they hypothesise may have contributed to its decline.
... antigen are the basis of the serological classification of Vibrio cholerae. The bacterium is classified into 206 "O" serogroups (Shimada et al., 1994;Yamai et al., 1997). Vibrio cholerae serogroups O1 and O139 cause epidemic cholera while the remaining serogroups rarely cause epidemics and are classified as Vibrio cholerae non-O1 and non-O139 and do not produce the cholera toxin (CT) . ...
... The isolates were examined by PCR for the presence of ctxA (a gene encoding the A subunit of cholera toxin), toxR regulatory gene for the cholera toxin prophage, inDS (encoding class 1 integrons) (Dalsgaard et al., 1999), int (encoding for SXT integrase) (Hochhut et al., 2001), strA, sul2 and tetA (encoding for genes conferring resistance to streptomycin, sulfamethoxazole and tetracycline respectively) (Hochhut et al., 2001;Yamai et al., 1997). Oligonucleotide primers were used in the PCR assays, their sequences and the amplicon sizes are described in Appendix 5. ...
Over the last decade cholera outbreaks have become common in some parts of Kenya. A number of recent studies have described the epidemiology of cholera in Kenya but there has been little information regarding the phenotypic and molecular characteristics of Vibrio cholerae in these outbreaks. The aim of this study was therefore to characterize Vibrio cholerae isolates from Kenya. A total of 168 Vibrio cholerae O1, biotype El Tor isolates collected between 2007 and 2010 from various cholera outbreaks in Kenya were studied. Their serotypes, antimicrobial susceptibility, genetic mechanisms of resistance, and their genetic relatedness were determined. Biochemical identification was performed using the API 20E identification system. Serologic identification was done by slide agglutination. Antimicrobial susceptibility testing was performed using the E-test method and disk diffusion. Polymerase Chain Reaction (PCR) was used to detect pathogenic and antibiotic resistant genes whereas Pulsed-field Gel Electrophoresis (PFGE) was used to determine their genetic diversity. Biochemical characterization confirmed all isolates as Vibrio cholerae belonging to serotypes Inaba and Ogawa, with Inaba being the predominant one. The isolates displayed reduced susceptibity towards ceftriaxone, chloramphenicol, doxycycline and streptomycin antimicrobials. Majority were resistant to amoxicillin, cotrimoxazole, erythromycin and nalidixic acid. Notably, 45% of the isolates were resistant to three or more of the antimicrobials recommended for cholera treatment. All were susceptible to ciprofloxacin, gentamicin and ofloxacin. Majority of the isolates were also resistant to O/129 Vibriostatic agent that is used to differentiate Vibrio species from closely related organisms. PCR results for detection of virulence genes revealed that the isolates harbored the cholera toxin, ctxA and/or the cholera toxin regulatory gene, toxR. They were found to harbor genetic determinants for antimicrobial resistance namely the SXT integrating conjugative element and the class one intergron. Genes that code for antimicrobial resistance were detected in these elements. Pulsed-field Gel Electrophoresis results suggest that two clones of Vibrio cholerae strains were circulating within Kenya. The finding that a majority of the Kenyan isolates were resistant towards cotrimoxazole and erythromycin suggest that these antimicrobials should not be used to treat cholera caused by current Vibrio cholerae O1 strains. Surveillance for antimicrobial drug resistance should continue among Vibrio cholerae isolates. The finding that most isolates were resistant towards the O/129 Vibriostatic agent suggests that the agent should not be used to characterize Kenyan isolates. Whole genome sequencing should be performed to better understand the genetic mechanisms of resistance and genetic relatedness of these isolates. The findings from this study will be presented to the Kenyan Ministry of Health and hopefully be used in policy making.
... Cholera remains a global threat to public health and a key indicator of lack of social development. Cholera, an acute diarrheal disease caused by gram-negative bacillus Vibrio cholerae of serogroup 01 and 0139 is associated with high morbidity and mortality [1][2][3]. ...
... Asymptomatic cases shed vibrios in their stools and serve as a potential source of infection to others. Symptomatic patients may also shed vibrios before the onset of illness and will continue to shed the organisms for about 1 to 2 weeks [1,3,4]. ...
Background
Cholera remains a disease of public health importance in Nigeria associated with high morbidity and mortality. In November 2014, the Nigeria Field Epidemiology and Laboratory Training Programme (NFELTP) was notified of an increase in suspected cholera cases in Gomani, Kwali Local Government Area. NFELTP residents were deployed to investigate the outbreak with the objectives of verifying the diagnosis, identifying risk factors and instituting appropriate control measures to control the outbreak.
Methods
We conducted an unmatched case-control study. We defined a cholera case as any person aged ≥5 years with acute watery diarrhea in Gomani community. We identified community controls. A total of 43 cases and 68 controls were recruited. Structured questionnaires were administered to both cases and controls. Four stool samples from case-patients and two water samples from the community water source were collected for laboratory investigation. We performed univariate and bivariate analysis using Epi-Info version 7.1.3.10.
Results
The mean age of cases and controls was 20.3 years and 25.4 respectively (p value 0.09). Females constituted 58.1% (cases) and 51.5%(controls). The attack rate was 4.3% with a case fatality rate of 13%. Four stool (100%) specimen tested positive for Vibrio cholerae. The water source and environment were polluted by indiscriminate defecation. Compared to controls, cases were more likely to have drank from Zamani river (OR 14.2, 95% CI: 5.5–36.8) and living in households(HH) with more than 5 persons/HH (OR 5.9, 95% CI: 1.3–27.2). Good hand hygiene was found to be protective (OR 0.3, 95% CI: 0.1–0.7).
Conclusion
Vibrio cholerae was the cause of the outbreak in Gomani. Drinking water from Zamani river, living in overcrowded HH and poor hand hygiene were significantly associated with the outbreak. We initiated hand hygiene and water treatment to control the outbreak.
... The V. cholerae population can currently be broken into 206 serogroups based on the presence of the major surface O-antigen (Yamai et al. 1997). A single serogroup expressing the O1 surface antigen gave rise to a monophyletic clade known as the pandemic-generating lineage or phylocore genome (PG) clade (Feng et al. 2008;Chun et al. 2009;Islam et al. 2017) (Fig. 3.2). ...
Vibrio cholerae, the agent of cholera, is a natural inhabitant of aquatic environments. Over the past decades, the importance of specific nutrients and micronutrients in the environmental survival, host colonization, and pathogenesis of this species has become increasingly clear. For instance, V. cholerae has evolved ingenious mechanisms that allow the bacterium to colonize and establish a niche in the intestine of human hosts, where it competes with commensals (gut microbiota) and other pathogenic bacteria for available nutrients. Here, we discuss the carbon and energy sources utilized by V. cholerae and what is known about the role of nutrition in V. cholerae colonization. We examine how nutritional signals affect virulence gene regulation and how interactions with intestinal commensal species can affect intestinal colonization.Keywords
Vibrio cholerae
Carbon utilizationNutrient uptakeHost colonizationHost–pathogen interaction
... The V. cholerae population can currently be broken into 206 serogroups based on the presence of the major surface O-antigen (Yamai et al. 1997). A single serogroup expressing the O1 surface antigen gave rise to a monophyletic clade known as the pandemic-generating lineage or phylocore genome (PG) clade (Feng et al. 2008;Chun et al. 2009;Islam et al. 2017) (Fig. 3.2). ...
The Vibrionaceae is a highly diverse family of aquatic bacteria. Some members of this ubiquitous group can cause a variety of diseases in humans ranging from cholera caused by Vibrio cholerae, severe septicemia caused by Vibrio vulnificus, to acute gastroenteritis by Vibrio parahaemolyticus. Planet Earth is experiencing unprecedented changes of planetary scale associated with climate change. These environmental perturbations paired with overpopulation and pollution are increasing the distribution of pathogenic Vibrios and exacerbating the risk of causing infections. In this chapter, we discuss various aspects of Vibrio infections within the context of the twenty-first century with a major emphasis on the aforementioned pathogenic species. Overall, we believe that the twenty-first century is posed to be both one full of challenges due to the rise of these pathogens, and also a catalyst for innovative and groundbreaking discoveries.KeywordsVibrio infectionsClimate changeCholeraGlobal warming
Vibrio parahaemolyticus
Vibrio vulnificus
... V. cholerae can be often isolated from aquatic environments and as a facultative human pathogen (Mohamad et al., 2019;Islam et al., 2020). They are Gram-negative curved rod bacteria comprising over 200 serogroups, with only two serogroups (O1 and O139) implicated in epidemic and pandemic cholera (Yamai et al., 1997;Domman et al., 2017). The O1 serogroup is further classified into El-Tor and Classical biotypes (Kaper et al., 1995). ...
Recurrent epidemics of cholera denote robust adaptive mechanisms of
Vibrio cholerae for ecological shifting and persistence despite variable
stress conditions. Tracking the evolution of pathobiological traits requires
comparative genomic studies of isolates from endemic areas. Here, we
investigated the genetic differentiation among V. cholerae clinical and
environmental isolates by highlighting the genomic divergence associated
with gene decay, genome plasticity, and the acquisition of virulence and
adaptive traits. The clinical isolates showed high phylogenetic relatedness
due to a higher frequency of shared orthologs and fewer gene variants in
contrast to the evolutionarily divergent environmental strains. Divergence of
the environmental isolates is linked to extensive genomic rearrangements
in regions containing mobile genetic elements resulting in numerous
breakpoints, relocations, and insertions coupled with the loss of virulence
determinants acf, zot, tcp, and ctx in the genomic islands. Also, four isolates
possessed the CRISPR-Cas systems with spacers specific for Vibrio phages
and plasmids. Genome synteny and homology analysis of the CRISPRCas
systems suggest horizontal acquisition. The marked differences in the
distribution of other phage and plasmid defense systems such as Zorya,
DdmABC, DdmDE, and type-I Restriction Modification systems among the isolates indicated a higher propensity for plasmid or phage disseminated
traits in the environmental isolates. Our results reveal that V. cholerae strains
undergo extensive genomic rearrangements coupled with gene acquisition,
reflecting their adaptation during ecological shifts and pathogenicity.
... Later, in 1883, Robert Koch isolated and detected the "Kommabacillus" using microscopy during an epidemic of cholera in Egypt, thus presenting evidence of the microbiological pathophysiology. The Vibrio cholerae serogroups were classi ed during the 1930's from outer membrane O-antigen polysaccharide composition and currently there are 206 known serogroups (6)(7)(8)(9). There are two O1 biotypes; classical" or El Tor and three distinct serotypes named Ogawa, Inaba and Hikojima. ...
Purpose (stating the main purposes and research question) Vibrio cholerae is classified in O-antigen polysaccharide outer membrane properties where O1 and O139 are strains that cause pandemics and epidemics while non-O1/non-O139 usually cause mild disease. The dynamic evolution of Vibrio cholerae involves new virulence factors through horizontal gene transfer and formerly nontoxigenic serogroups are being reported as causing increasingly severe forms of human disease. Our purpose was to investigate serogroup and virulence factors in one imported isolate from Vietnam and compare these to virulence factors seen in different strains of Vibrio cholerae.
Methods This is an observational study where we have serotyped one isolate of imported Vibrio cholerae from Vietnam to Denmark and performed whole genome sequencing to identify known virulence genes and furthermore studied the epidemiology of virulence in pathogenic strains of Vibrio cholerae.
Results We have identified virulence factors in our isolate that are recently discovered and one toxin, MakA, has not previously been reported from an Asian strain. The isolate was found to be a serogroup non-O1/non-O139 strain, however, sequence analysis gave a 96, 6% ID match of the wbfZ gene, stipulating our isolate to belong to either serogroup O22 or O139.
Conclusions Looking at the combination of virulence factors of the isolate we suggest the finding of a rough variant of a nontoxigenic Vibrio cholerae O139 rather than a O22 serogroup version. This is a rare finding in a clinical isolate.
... This genetic mutation type allows the organism to effect increased virulence and pathogenesis on individual who are previously immune to O1 V. cholerae, hence adults are it's major host. Suffix to say that the somatic antigen carries the epitope for attachment and pathogenicity, hence similar pathogenic effects are expressed amongst O1/O139 members that are agglutinating and other nonagglutinating types (also known as non-O1/non-O139) eg; O5, O2, 04, O27, O37, O53, O65, O75, O141, etc. (Takahashi et al. 2021;Aydanian et al.2011;Tobin-D'Angelo et al. 2008;Nesper et al. 2002;Stine et al. 2000;Yamai et al. 1997). From the study of Aydanian and his group, it was hypothesized that pathogenic O1/O139 V. cholerae members have the tendency to mutate or change or exchange their somatic antigenic genes which confirms their genetic heterogeneity or plasticity (Aydanian et al. 2011). ...
Somatic antigen agglutinable type Vibrio cholerae of 1/139 (SAAT-Vc-1/139) members or O1/O139 Vibrio cholerae have been described by various investigators as choleragenic due to their increase pathogenic potential and production of choleragen. Reported cholera outbreak cases around the World have been associated with these choleragenic Vibrio cholerae with high case fatality involving various educational, human, governmental, animal and financial resources. These Vibrio members have shown genealogical and phylogenetic relationship with the somatic antigen non-agglutinable strains of 1/139 Vibrio cholerae (SANAS- Vc -1/139) or O1/O139 non-agglutinating Vibrio cholerae (O1/O139-NAG-Vc). The O1/O139-NAGVc members have been reported to be implicated in most cholera/cholera-like cases, sporadic cases, diarrhea, production of cholera toxin and transmitted via consumption and/or contact with contaminated water/seafood. Some reported cases of cholera outbreaks, sporadic cases and observed change in nature has also been tracable to these non-agglutinable Vibrio members (O1/O139-NAGVc) yet there is a sustained paucity of reports on the non-agglutinable V. cholerae members implication in cholera outbreak. The emergence of fulminating extraintestinal and systemic Vibriosis is another aspect of SANAS- Vc -1/139 involvement which has received low attention in terms of research driven interest. This review addresses the need to appraise and continue in research based studies on the somatic antigen non-serogroup agglutinable type-1/139 Vibrio cholerae members which are currently prevalent in water bodies, fruits/vegetables, foods and terrestrial environment. Our opinion is a summative of interest in integrated surveillance studies, management/control of cholera outbreaks as well as diarrhea and other disease related cases both in the rural, suburban and urban metropolis.
... This genetic mutation type allows the organism to effect increased virulence and pathogenesis on individual who are previously immune to O1 V. cholerae, hence adults are it's major host. Suffix to say that the somatic antigen carries the epitope for attachment and pathogenicity, hence similar pathogenic effects are expressed amongst O1/O139 members that are agglutinating and other nonagglutinating types (also known as non-O1/non-O139) eg; O5, O2, 04, O27, O37, O53, O65, O75, O141, etc. (Takahashi et al. 2021;Aydanian et al.2011;Tobin-D'Angelo et al. 2008;Nesper et al. 2002;Stine et al. 2000;Yamai et al. 1997). From the study of Aydanian and his group, it was hypothesized that pathogenic O1/O139 V. cholerae members have the tendency to mutate or change or exchange their somatic antigenic genes which confirms their genetic heterogeneity or plasticity (Aydanian et al. 2011). ...
Somatic antigen agglutinable type-1/139 Vibrio cholerae (SAAT-1/139-Vc) members or O1/O139 V. cholerae have been described by various investigators as pathogenic due to their increasing virulence potential and production of choleragen. Reported cholera outbreak cases around the world have been associated with these choleragenic V. cholerae with high case fatality affecting various human and animals. These virulent Vibrio members have shown genealogical and phylogenetic relationship with the avirulent somatic antigen non-agglutinable strains of 1/139 V. cholerae (SANAS-1/139- Vc) or O1/O139 non-agglutinating V. cholerae (O1/O139-NAG-Vc). Reports on implication of O1/O139-NAGVc members in most sporadic cholera/cholera-like cases of diarrhea, production of cholera toxin and transmission via consumption and/or contact with contaminated water/seafood are currently on the rise. Some reported sporadic cases of cholera outbreaks and observed change in nature has also been tracable to these non-agglutinable Vibrio members (O1/O139-NAGVc) yet there is a sustained paucity of research interest on the non-agglutinable V. cholerae members. The emergence of fulminating extraintestinal and systemic vibriosis is another aspect of SANAS-1/139- Vc implication which has received low attention in terms of research driven interest. This review addresses the need to appraise and continually expand research based studies on the somatic antigen non-serogroup agglutinable type-1/139 V.cholerae members which are currently prevalent in studies of water bodies, fruits/vegetables, foods and terrestrial environment. Our opinion is amassed from interest in integrated surveillance studies, management/control of cholera outbreaks as well as diarrhea and other disease-related cases both in the rural, suburban and urban metropolis.
... Later, in 1883, Robert Koch isolated and detected the "Kommabacillus" using microscopy during an epidemic of cholera in Egypt, thus presenting evidence of the microbiological pathophysiology. The Vibrio cholerae serogroups were classi ed during the 1930's from outer membrane O-antigen polysaccharide composition and currently there are 206 known serogroups (6)(7)(8)(9). There are two O1 biotypes; classical" or El Tor and three distinct serotypes named Ogawa, Inaba and Hikojima. ...
Purpose (stating the main purposes and research question) Vibrio cholerae is classified in O-antigen polysaccharide outer membrane properties where O1 and O139 are strains that cause pandemics and epidemics while non-O1/non-O139 usually cause mild disease. The dynamic evolution of Vibrio cholerae involves new virulence factors through horizontal gene transfer and formerly nontoxigenic serogroups are being reported as causing increasingly severe forms of human disease. Our purpose was to investigate serogroup and virulence factors in one imported isolate from Vietnam and compare these to virulence factors seen in different strains of Vibrio cholerae .Methods
We have serotyped one isolate of imported Vibrio cholerae from Vietnam to Denmark and performed whole genome sequencing to identify known virulence genes. ResultsWe have identified virulence factors in our isolate that are recently discovered and one toxin, MakA, has not previously been reported from an Asian strain. The isolate was found to be a serogroup non-O1/non-O139 strain, however, sequence analysis gave a 96, 6% ID match of the wbfZ gene, stipulating our isolate to belong to either serogroup O22 or O139. Conclusions
Looking at the combination of virulence factors of the isolate we suggest the finding of a rough variant of a nontoxigenic Vibrio cholerae O139 rather than a O22 serogroup version. This is a rare finding in a clinical isolate.
... Cholera, an acute dehydrating diarrhoea caused by the aquatic bacterial pathogen Vibrio cholerae, dates back to antiquity in the form of epidemics and pandemics throughout the World (Politzer, 1959;Kaper et al., 1995;Faruque et al., 1998a). Vibrio cholerae has been classified into more than 200 serogroups based on the somatic O antigen from which O1 and O139 serogroups produce cholera toxin and thus carries pathogenic strains (Yamai et al., 1997). In the beginning of 19th century, the V. cholerae O1 El Tor biotype was supposed to be responsible for all epidemics and endemic cholera worldwide. ...
The genome of Vibrio cholerae O139 strains has undergone cryptic changes since its first emergence in 1992 in South India. This study aimed to determine the presence of genotypic changes marked in ctxB, tcpA and rstR genes located within the CTX prophages among the strains of V. cholerae O139 isolated from 1999 to 2017 in Odisha. Antibiotic susceptibility test was conducted on 59 V. cholerae O139 strains. A conventional PCR assay was done for ctxB gene typing followed by sequencing along with identification of rstR and tcpA gene. Pulsed-field gel electrophoresis (PFGE) was carried out to reveal clonal variations among the V. cholerae O139 strains. Among V. cholerae O139 isolates more than 60% showed resistance to ampicillin, co-trimoxazole, furazolidone, streptomy-cin, neomycin and nalidixic acid. The ctxB sequencing and rstR allele-specific PCR assay revealed the presence of three genotypes 1, 3 and 4 with at least one copy of CTX Calc φ in addition to CTX ET and CTX Cl prophages in V. cholerae O139 isolates. PFGE analysis revealed 13 pulsotypes with two clades having 60% similarity among V. cholerae O139 strains. The circulating V. cholerae O139 strains in Odisha showed variation in genotypes with multiple clonal expansions over the years.
... For the determination of serogroups O1 and O139, we used commercially available antisera (Denkaseiken, Tokyo, Japan). Serogroups other than O1 and O139 were determined using 206 O group-specific serum supplied by National Institute of Infectious Diseases of Japan (Yamai et al., 1997 to the DDBJ Sequenced Read Archive (DRA), and each accession number is listed in Table 2. ...
Cholera toxin (CT)-producing Vibrio cholerae O1 and O139 cause acute diarrheal disease and are proven etiological agents of cholera epidemics and pandemics. On the other hand, V. cholerae non-O1/non-O139 are designated as non-agglutinable (NAG) vibrios and are not associated with epidemic cholera. The majority of NAG vibrios do not possess the gene for CT ( ctx ). In this study, we isolated three NAG strains (strains No. 1, 2, and 3) with ctx from pond water in Kolkata, India, and examined their pathogenic properties. The enterotoxicity of the three NAG strains in vivo was examined using the rabbit ileal intestinal loop test. Strain No. 1 induced the accumulation of fluid in the loop, and the volume of fluid was reduced by simultaneous administration of anti-CT antiserum into the loop. The volume of fluid in the loop caused by strains No. 2 and 3 was small and undetectable, respectively. Then, we cultured these three strains in liquid medium in vitro at two temperatures, 25°C and 37°C, and examined the amount of CT accumulated in the culture supernatant. CT was accumulated in the culture supernatant of strain No.1 when the strain was cultured at 25°C, but that was low when cultured at 37°C. The CT amount accumulated in the culture supernatants of the No. 2 and No. 3 strains was extremely low at both temperature under culture conditions examined. In order to clarify the virulence properties of these strains, genome sequences of the three strains were analyzed. The analysis showed that there was no noticeable difference among three isolates both in the genes for virulence factors and regulatory genes of ctx . However, vibrio seventh pandemic island-II (VSP-II) was retained in strain No. 1, but not in strains No. 2 or 3. Furthermore, it was revealed that the genotype of the B subunit of CT in strain No. 1 was type 1 and those of strains No. 2 and 3 were type 8. Histopathological examination showed the disappearance of villi in intestinal tissue exposed to strain No. 1. In addition, fluid accumulated in the loop due to the action of strain No. 1 had hemolytic activity. This indicated that strain No. 1 may possesses virulence factors to induce severe syndrome when the strain infects humans, and that some strains of NAG vibrio inhabiting pond water in Kolkata have already acquired virulence, which can cause illness in humans. There is a possibility that these virulent NAG vibrios, which have acquired genes encoding factors involved in virulence of V. cholerae O1, may emerge in various parts of the world and cause epidemics in the future.
... Vibrio cholerae, a Gram-negative bacterium is the causative agent of cholera [6]. Based on somatic 'O' antigen, more than 206 serogroups of V. cholerae has been identified and among them, V. cholerae O1 and O139 are the epidemic serogroups [7]. V. cholerae O1 has two major serotypes, Ogawa and Inaba. ...
Cholera is one of the major public health problems in the state of Odisha, India since centuries. The current paper is a comprehensive report on epidemiology of cholera in Odisha, which was documented from 1993. PubMed and Web of Knowledge were searched for publications reporting cholera in Odisha during the period 1993–2015. The search was performed using the keywords ‘Odisha’ and/or ‘Orissa’ and ‘Cholera’. In addition, manual search was undertaken to find out relevant papers. During the study period, a total of 37 cholera outbreaks were reported with an average of >1.5 cholera outbreaks per year and case fatality ratio was 0.3%. Vibrio cholerae O1 Ogawa serotype was the major causative agent in most of the cholera cases. The recent studies demonstrated the prevalence of V. cholerae O1, El Tor variants carrying ctxB1 , ctxB7 and Haitian variant tcpA allele associated with polymyxin B sensitivity and these variants are replacing the proto type El Tor. The first report of variant ctxB7 in Odisha during super-cyclone 1999 predicted its emergence and subsequent spread causing cholera outbreaks. The prevalence of multidrug-resistant V. cholera e at different time periods created alarming situation. The efficacy trial of oral cholera vaccine (OCV, Shanchol) in a public health set-up in Odisha has shown encouraging results which should be deployed for community level vaccination among the vulnerable population. This paper has taken an effort to disseminate the valuable information of epidemiology of cholera that will influence the policy-makers and epidemiologists for constant surveillance in other parts of Odisha, India and around the globe.
... Vibrio cholerae is a Gram-negative, rod-shaped bacterium. It has more than 200 serogroups based on the surface 'O' antigen [1]. Among these, V. cholerae strains belonging to the O1 and O139 serogroups are associated with epidemic cholera a ecting millions of people every year [2]. ...
Introduction. Cholix toxin (ChxA) is an ADP-ribosylating exotoxin produced by Vibrio cholerae . However, to date, there is no quantitative assay available for ChxA, which makes it difficult to detect and estimate the level of ChxA produced by V. cholerae .
Hypothesis/Gap Statement. It is important to develop a reliable and specific quantitative assay to measure the production level of ChxA, which will help us to understand the role of ChxA in V. cholerae pathogenesis.
Aim. The aim of this study was to develop a bead-based sandwich ELISA (bead-ELISA) for the quantification of ChxA and to evaluate the importance of ChxA in the pathogenesis of V. cholerae infection.
Methodology. Anti-rChxA was raised in New Zealand white rabbits, and Fab-horse radish peroxidase conjugate was prepared by the maleimide method to use in the bead-ELISA. This anti-ChxA bead-ELISA was applied to quantify the ChxA produced by various V. cholerae strains. The production of ChxA was examined in different growth media such as alkaline peptone water (APW), Luria-Bertani broth and AKI. Finally, the assay was evaluated using a mouse lethality assay with representative V. cholerae strains categorized as low to high ChxA-producers based on anti-ChxA bead-ELISA.
Results. A sensitive bead-ELISA assay, which can quantify from 0.6 to 60 ng ml ⁻¹ of ChxA, was developed. ChxA was mostly detected in the extracellular cell-free supernatant and its production level varied from 1.2 ng ml ⁻¹ to 1.6 µg ml ⁻¹ . The highest ChxA production was observed when V. cholerae strains were cultured in LB broth, but not in APW or AKI medium. The ChxA-producer V. cholerae strains showed 20–80 % lethality and only the high ChxA II-producer was statistically more lethal than a non-ChxA-producer, in the mice model assay. ChxA I and II production levels were not well correlated with mice lethality, and this could be due to the heterogeneity of the strains tested.
Conclusion. ChxA I to III was produced mostly extracellularly at various levels depending on strains and culture conditions. The bead-ELISA developed in this study is useful for the detection and quantification of ChxA in V. cholerae strains.
... Among 206 O-serogroups of V. cholerae, there are only two major pathogenic strains: serogroups O1 and O139. 4 The O1 serogroup is subdivided into two biotypes based on phenotypic and genotypic differences, namely, classical and El Tor. The classical strain is responsible for first six pandemics, and the seventh pandemic that began in 1961 is associated with the El Tor strain. ...
Because of the emergence of multidrug-resistant pathogenic bacteria, there is a growing interest for the development of an efficient alternative to antibiotics. Gold nanoparticles (AuNPs) are promising candidates due to their inherent non-toxicity and can be used as effective carriers of drugs. Cholera caused by Gram-negative Vibrio cholerae is still a potential threat in many developing countries. Virstatin, a small molecule, has been reported to inhibit virulence regulation in V. cholerae. Herein, we report an efficient synthesis of virstatin-conjugated gold nanoparticles (VL-AuNPs) and their antibacterial efficacy against the El Tor biotype of V. cholerae (VcN16961). The spherical-shaped NPs have an average diameter of ∼17 nm. The uniqueness of VL-AuNPs relies in the enhanced antibacterial efficacy compared to virstatin, as evidenced from the inhibitory concentration obtained from growth kinetics, and attributed to the inhibition of ATPase activity and DNA damage. More importantly, the expression of cholera toxin, the most important virulence factor of V. cholera, is reduced to a far greater extent than by any of the component molecules. The effect of VL-AuNPs on VcN16961 was monitored using various assays such as confocal microscopy, FACS, fluorescence spectroscopy, and so on. Overall, VL-AuNPs could be a potential candidate for the use as an effective agent for combating diarrheal diseases caused by V. cholera.
... 6. Virulence factors and genetic diversity of environmental V. cholerae vis-à-vis clinical isolates V. cholerae is known to be autochthonous to marine and estuarine ecosystems, which act as a source and reservoir for human infections [25]. Based on variations in cell-surface lipopolysaccharides, almost 200 serogroups (O1-O200) are known for V. cholerae, out of which only serogroups O1 and O139 are pathogenic, and are associated with cholera [26][27][28][29][30]. The other serogroups are collectively called as non-O1 non-O139 V. cholerae, which are seldom associated with diarrheal diseases less severe than cholera [31]. ...
In the freshwater environment of north India, cholera appears seasonally in form of clusters as well as sporadically, accounting for a significant piece of the puzzle of cholera epidemiology. We describe a number of cholera outbreaks with an average attack rate of 96.5/1000 but an overall low case fatality (0.17). Clinical cholera cases coincided with high rainfall and elevated temperatures, whereas isolation of V. cholerae non-O1 non-O139 from water was dependent on temperature (p < 0.05) but was independent of rainfall and pH (p > 0.05). However, isolation from plankton samples correlated with increased temperature and pH (p < 0.05). A lag period of almost a month was observed between rising temperature and increased isolation of V. cholerae from the environment, which in succession was followed by an appearance of cholera cases in the community a month later. Our results suggested that the aquatic environment can harbor highly divergent V. cholerae strains and serve as a reservoir for multiple V. cholera virulence-associated genes that may be exchanged via mobile genetic elements. In agreement with PFGE, AFLP data also proved that the V. cholerae O1 population was not clonal but was closely related. Our investigation did not support the concept that seasonal cholera outbreaks occur by movement of a single clonal strain across the region, as the clinical isolates from the same years were clearly different, implying that continuous evolution of V. cholerae O1 strains occurs in the cholera endemic area. Interestingly, the viable but non-culturable (VBNC) V. cholerae O1 cells were demonstrated in 2.21% samples from natural water bodies in addition to 40.69% samples from cholera-affected areas respectively. This suggests that aquatic environs do harbor the pathogenic O1 strain, though the isolation of culturable V. cholerae O1 is a rare event in the presence of relatively abundant non-O1 non-O139 isolates.
... On the basis of the variable somatic O antigen composition, 206 serogroups of Vibrio cholerae have been recognized [2], but not all of them cause the severe diarrheal disease known as cholera. Seven cholera pandemics have been reported throughout history. ...
Background
Of the hundreds of Vibrio cholerae serogroups, O1 and O139 are the main epidemic-causing ones. Although non-O1/non-O139 serogroups rarely cause epidemics, the possibility exists for strains within them to have pathogenic potential.
Results
We selected 25 representative strains within 16 V. cholerae serogroups and examined their genomic and functional characteristics. We tentatively constructed a gene pool containing 405 homologous gene clusters, which is well organized and functions in O-antigen polysaccharide (O-PS) synthesis. Our network analysis indicate that great diversity exists in O-PS among the serogroups, and several serogroup pairs share a high number of homologous genes (e.g., O115 and O37; O170 and O139; O12 and O39). The phylogenetic analysis results suggest that a close relationship exists between serogroups O170, O89 and O144, based on neighbor-joining (NJ) and gene trees, although serogroup O159 showed an inconsistent phylogenetic relationship between the NJ tree and the gene tree, indicating that it may have undergone extensive recombination and horizontal gene transfer. Different phylogenetic structures were observed between the core genes, pan genes, and O-PS genes. The virulence gene analysis indicated that the virulence genes from all the representative strains may have their sources from four particular bacteria (Pseudomonas aeruginosa, V. vulnificus, Haemophilus somnus and H. influenzae), which suggests that V. cholerae may have exchanged virulence genes with other bacterial genera or species in certain environments. The mobile genetic element analysis indicated that O159 carries nearly complete VSP-II and partial VPI-1 and VPI-2, O170 carries partial VPI-1 and VPI-2, and several non-O1/non-O139 strains contain full or partial VPI-1 and VPI-2. Several genes showing evidence of positive selection are involved in chemotaxis, Na + resistance, or cell wall synthesis, suggestive of environmental adaptation.
Conclusions
This study reports on the newly sequenced O159 and O170 genomes and their comparisons with other V. cholerae serogroups. The complicated O-PS network of constituent genes highlights the detailed recombination mechanisms that have acted on the serogroups’ genomes. The serogroups have different virulence-related gene profiles, and there is evidence of positive selection acting on other genes, possibly during adaptation to different environments and hosts.
Electronic supplementary material
The online version of this article (10.1186/s12864-019-5603-7) contains supplementary material, which is available to authorized users.
... Differences in the sugar composition of the heat-stable surface somatic "O" antigen are the basis of the serological classification of V. cholerae first described by [2]; currently the organism is classified into 206 O serogroups [3,4]. ...
Stool specimens were collected from (136) patients with watery diarrhea aged (from 5 months to 80 years) prior administration to antimicrobial agents who were referred to Hilla teaching hospital (Emergency department) during a period from (September to December 2008). This study found that 44 (32.35%) suspected isolates of Vibrio cholerae 23(52.3%) male and 21 (47.7%) female. All isolates were proven to be Vibrio cholerae in central public health laboratory in Baghdad. Regarding to the serotyping of Vibrio cholerae this study found that all isolates have only Inaba serotype. The virulence factors were detected in all isolates was produce siderophores and colonization factor antigens. الخالصة م خروج عينات جمع تم اسة الدر هذه خالل من ن (136) (بين أعمارهم اوح تتر مائي إسهال من يعانون يض مر 5 إلى أشهر 08)سنة األول كانون شهر حتى أيلول (شهر من ة للفتر)ارئ التعليمي(الطو الحلة مستشفى إلى ا أحيلو ممن 8880 العينات اخذ على حرصنا )وقد .حيوي مضاد ألي المرضى تعاطي قبل عزل تم وقد 44 ب مشتبه ا كولير لة عز بينهم من ها } (5825)% 85 (و ذكر 4424)% 82 أنثى { مختبر في صحتها أكدت الت العز جميع. (المصلي النمط أظهرت قد الت العز كل إن وجد فقد الت العز لهذه المصلية األنماط يخص فيما .بغداد في المركزي الصحة Inaba) ,فقط و اوة الضر امل عو أما ال لها الت العز جميع ظهرت فقط يا البكتر لهذه االستيطان امل عو وتمتلك ات السايدروفور إنتاج على قابليه .
... The causative agent of the infectious diarrheal disease cholera is Vibrio cholerae. Depending on the lipopolysaccharide O-antigen present, V. cholerae can be divided into over 200 serogroupshowever, only two, O139 and O1, have endemic or pandemic potential [1,2]. Serogroup O139 has been subject to cases of mild diarrhea, mainly in Southeast Asia [3,4], while serogroup O1 is considered to be more clinically relevant as it has been shown to be responsible for all previously reported global pandemics since 1817. ...
Vibrio cholerae is a motile gram-negative bacterium found in brackish water and the etiological agent of the fecal-oral disease cholera. Classical and El Tor are two main biotypes that make up the V. cholerae O1 serogroup, which each display unique genotypic and phenotypic characteristics that allow for reliable biotype characterization. While treatment for cholera is much the same despite the causative strain's biotype, such classification can be imperative for laboratory experiments and may have broader impacts in the biomedical field. In the early 2000s, clinical isolates were identified that contained genotypic and phenotypic traits from both biotypes. The newly identified hybrids, termed El Tor variants, have caused clinical and environmental isolate biotype identification to be more complicated than previous single-assay identification. Herein, we describe a series of PCR-based genetic screens (tcpA and ctxB) and phenotypic assays (polymyxin B resistance, citrate metabolism, proteolytic activity, hemolytic activity, motility, and Voges-Proskauer). Together, these assays are used for reliable biotype characterization of V. cholerae clinical (and environmental) isolates.
... Leibniz) . The strains of genus V. cholera classified to serogroups according to epitopic different for lipopolysacharide for surface of cell (Yamai et al. 1997) The serogroup O 1 and O 139 among 210 that causal agent for cholera (Revera,et al.2002). ...
Cholera is one of the most important epidemic diseases globally. It is causing of morbidity and mortality in the world. Severe watery diarrhea causes a composite process involving several component that help them reach the lining of the small intestine, form colonies and generate bacterial toxins. This survey was carried out to discover the genetic patterns of clinical isolates according to the presence or absence of toxic genes for the city of Diwaniyah in southern Iraq. Sixty isolates were isolated from patients with cholera. The isolates included the center of the city and the surrounding rural areas. Biochemical and serological diagnosis. All the isolates were V. cholera serogroup O 1 of the serotyping Ogawa in biotype El Tor. Genetic testing was carried out using PCR technique and base on the presence or absence of toxin genes. Three genotypes were identified for the region. © 2018 Journal of Pure and Applied Microbiology. All rights reserved.
... Vibrio cholerae is not homogeneous and can include over 200 serogroups based on its O antigen (Shimada et al., 1994;Yamai et al., 1997). Of all these serogroups only serogroups O1 and O139 are able to cause cholera epidemics or pandemics. ...
Vibrio cholerae, with strains that cause cholera, is a motile, Gram-negative curved rod belonging to the family Vibrionaceae. Although approximately 200 recognized O serogroups have been identified, only serogroups O1 and O139 strains are known to cause severe disease and cholera pandemics. Intestinal and/or extra-intestinal infections with non-O1 and non-O139 serogroups or non-toxigenic O1 strains are seldom found and seem to have little impact on public health. Serogroup O1 and O139 pandemic strains exist as natural inhabitants of aquatic ecosystems, making them facultative human pathogens. V. cholerae serogroup O1 has two biotypes (classical and El Tor) and three serotypes (Ogawa, Inaba and Hikojima). The most prevalent serotype is Ogawa, whereas Hikojima is very rare and unstable in the environment. Non-O1 and non-O139 V. cholerae strains are more frequently isolated from rivers and estuarine areas compared to O1 and O139 strains. There is evidence that the cholera toxin (CT)-encoded phage CTXϕ can transduce these non-toxigenic environmental strains, converting them into toxigenic strains, an event that has been postulated to also take place in the gastrointestinal environment resulting in the detection of toxigenic strains.
In the past, the permanence of toxigenic V. cholerae in the environment was considered short and cholera outbreaks have been mainly driven by fecal-oral transmission. Currently, it has been found that V. cholerae could survive for a long time in the water, assuming a viable, but non-culturable state. This finding pointed to a new hypothesis, namely that an environmental reservoir of V. cholerae is responsible for endemic cholera, and a corresponding cholera epidemiology framework was formulated that incorporates an envionmental V. cholerae reservoir. The role of the aquatic environment on maintenance of cholera dynamics depends on the sanitary condition of the community. Endemism in a well-sanitized community requires a permanent environmental reservoir, while endemism in a poor community requires only a transient reservoir.
Onset of cholera as a disease is the result of a multifactorial process, involving several genes encoding virulence factors that aid V. cholerae in its colonization, coordinated expression of virulence factors, and toxigenicity. Vibrio cholerae also acquire virulence genes in a step-by-step process, in which a pathogenicity island and a temperate bacteriophage play important roles. Globally, cholera represents an estimated burden of 1.4 to 4.3 million cases and 28,000 to 142,000 deaths per year. Even though considerable efforts have been made by many countries to contain the spread of cholera, it is now endemic in many countries and there is growing concern over the increasing number of people living in unsanitary conditions and being at risk of contracting cholera and other epidemic-prone diarrhoeal diseases.
This chapter aims to provide the reader with a broad understanding of recent discoveries of V. cholerae and new recombinant V. cholerae biotypes and an outlook toward future developments. Using the very latest international scientific research, this chapter outlines historical perspective and classification, methods (molecular and culture-based) proposed for the detection and isolation in waters and environmental occurrence, persistence and survival of Vibrio cholerae and their biotypes, the route of transmission and the global distribution of cholera as well as its control by vaccination and good sanitation and hygiene interventions to reduce the incidence of cholera outbreaks. A comprehensive and multidisciplinary approach to cholera prevention and control is provided to assist communities and policy-makers in averting cholera outbreaks.
... It is autochthonous to the aquatic environment, especially in brackish and estuarine systems [8][9][10]. V. cholerae is a heterogeneous species and at least 206 serogroups have been identified [11], but only a few are known to cause disease in humans. There are only two serogroups, O1 and O139 that so far have been recognized as having the potential to cause epidemic cholera. ...
Please cite this article as: Jangampalli Adi P, Naidu JR, Matcha B, Multiplex quantification of Escherichia coli, Salmonella typhi and Vibrio cholera with three DNA targets in single reaction assay, Microbial Pathogenesis (2017), Abstract Escherichia coli (E. coli), Salmonella typhi and Vibrio cholera harmful pathogens, which causes various diseases in humans. Rapid diagnosis of bacterial infection is important for patient management and appropriate therapy during the early phase of the bacteria-induced disease. Among the existing techniques for identifying pathogens were less sensitive and time-consuming processes. In the present study total, 48 clinical 31 blood and 17 urine samples of patients suspected with the infections were collected from SVRR Hospital and used to detect the pathogens. Multiplex polymerase chain reaction (PCR) assay was set to design for the detection of Escherichia coli (ATCC 43895), Salmonella typhi (ATCC 19430) and Vibrio cholera O from the different clinical samples. So the rapid diagnosis of Escherichia coli (E. coli), Salmonella and Vibrio cholera pathogens can be done simultaneously in single multiplex PCR assay by using species-specific primers with adjusted PCR conditions. Through this approach, the results represented without of 31 blood samples 1 to 17 shows the positive with E. coli and remaining 14 only 11 were correlated with multiplex results of E. coli and Vibrio cholera, remaining the urine samples all are positive with 17 samples correlate with the Salmonella typhi. Through the high specificity benefits of excellent sensitivity, with high resolution and reproducibility. This method of results proved and illustrates the best potential of the system for diagnosing the infectious disease with modern trends.
Cholera, caused by _V. cholerae_, needs rapid diagnosis because of its threat for rapid spread. Recent molecular diagnosis by PCR assay is more advantageous than the conventional methods. The bottleneck in PCR diagnosis lies in the delay in template DNA extraction of _V. cholerae_, which is the basic requirement. This study describes a simple, less expensive, and rapid template DNA extraction method to lessen the total time for PCR diagnosis of _V. cholerae._ To obtain template DNA, our method involves boiling of _V. cholerae_ suspension in distilled water (takes 18-24 hours) instead of boiling the suspension in broth medium, which is a lengthy process (takes 72 hours). The validation of our template DNA was conducted using 40 _V. cholerae_ O1 strains that were confirmed previously, and its usefulness was checked on 20 clinical strains of _V. cholerae_ O1 isolated from acute diarrhea patients; results were compared with those of conventional template DNA. The analysis of our template DNA in simplex and quadruplex PCR assays revealed the presence of _ctxA_, _tcpA _(El Tor), _rfb _(O1), _ToxR_, _ctxB_, _zot_, _ace,rst _, and _OmpW _genes in _V. cholerae _O1. The comparison of the results of PCR assays using the template DNA from both sources showed equal results and matched correctly. The sensitivity of our template DNA was 1.5x103 CFU per assay. Our template DNA extraction method is simple, less expensive, and rapid, and it can be employed for early diagnosis of _V. cholerae_ during outbreaks, in research laboratories, and in hospital setups where infrastructures are available.
O V. cholerae sorogrupo O1 é o agente etiológico da cólera pandêmica, sendo considerado dentre os víbrios patogênicos ao homem, o mais importante. Os sintomas das infecções por esta bactéria variam de diarréia branda a doença grave podendo até levar a óbito. Dentre os alimentos marinhos, as ostras representam uma das principais vias na transmissão de cólera. Os métodos convencionais para detecção do V. cholerae O1 são laboriosos e demorados havendo, portando, a necessidade de implantar métodos rápidos, sensíveis, específicos, simples e de baixo custo. O objetivo deste estudo foi avaliar a técnica de aglutinação de partículas de látex sensibilizadas com anticorpo monoclonal (AcMo) na detecção de V. cholerae O1 em ostras, contaminadas laboratorialmente. A técnica de aglutinação com látex sensibilizado detectou 1,2x102 UFC da bactéria (diluição 1/32). As amostras de ostras utilizadas para contaminação originalmente não continham V. cholerae, mas outras bactérias foram detectadas, tais como: Proteus mirabilis, Pseudomonas spp. e outros víbrios. O presente estudo demonstrou que a detecção de V. cholerae em alimentos foi reduzida para 18 horas, considerando que pela metodologia convencional a análise é finalizada, em média, em 7 dias. O AcMo produzido apresentou uma sensibilidade e especificidade de 100% para V. cholerae.
Cholera is a severe diarrheal disease that claims approximately 30,500 lives annually, mainly in regions with limited access to clean water. Vibrio cholerae , the causative agent, has sparked seven pandemics in recent centuries, with the current one being the most prolonged. V. cholerae pathogenesis hinges on its ability to switch between low and high cell density gene regulatory states, enabling transmission between host and the environment.
Previous researchers created a transposon mutant library for V. cholerae to support investigations aimed toward uncovering the genetic determinants of its pathogenesis. However, subsequent sequencing uncovered a mutation in the gene luxO of the parent strain, rendering mutants unable to exhibit high cell density behaviors. In this study, we used chitin-independent natural transformation to move transposon insertions from these low cell density mutants into a wildtype genomic background. Library transfer was aided by a novel gDNA extraction we developed using thymol, which also showed marked vibrio-specific activity. The resulting Grant Library comprises 3,102 unique transposon mutants, covering 79.8% of V. cholerae’s open reading frames. Whole genome sequencing of randomly selected mutants demonstrates 100% precision in transposon transfer to cognate genomic positions of the recipient strain. Notably, luxO mutations transferred at a low frequency only with insertions near luxO . Our research uncovered density-dependent epistasis in motility genes, relevant to V. cholerae pathogenesis. Additionally, Grant Library mutants retain a plasmid conferring natural competence, enabling rapid, scarless genomic editing. In summary, the Grant Library reintroduces organismal relevant genetic contexts absent in the low cell density locked library equivalent.
The Vibrio Type VI Secretion System (T6SS) is a harpoon-like nanomachine that serves as a defense system and is encoded by approximately 25% of all gram-negative bacteria. In this chapter, we describe the structure of the T6SS in different Vibrio species and outline how the use of different T6SS effector and immunity proteins control kin selection. We summarize the genetic loci that encode the structural elements that make up the Vibrio T6SSs and how these gene clusters are regulated. Finally, we provide insights into T6SS-based competitive dynamics, the role of T6SS genetic exchange in those competitive dynamics, and roles for the Vibrio T6SS in virulence.Keywords
Vibrio cholerae
Type VI secretion systemBacterial competition
Cholera was first described in the areas around the Bay of Bengal and spread globally, resulting in seven pandemics during the past two centuries. It is caused by toxigenic Vibrio cholerae O1 or O139 bacteria. Cholera is characterised by mild to potentially fatal acute watery diarrhoeal disease. Prompt rehydration therapy is the cornerstone of management. We present an overview of cholera and its pathogenesis, natural history, bacteriology, and epidemiology, while highlighting advances over the past 10 years in molecular epidemiology, immunology, and vaccine development and deployment. Since 2014, the Global Task Force on Cholera Control, a WHO coordinated network of partners, has been working with several countries to develop national cholera control strategies. The global roadmap for cholera control focuses on stopping transmission in cholera hotspots through vaccination and improved water, sanitation, and hygiene, with the aim to reduce cholera deaths by 90% and eliminate local transmission in at least 20 countries by 2030.
Bacteria are cosmopolitan in nature and are present even inside Human gut, lungs, and on skin surfaces. Most of the bacteria are beneficial, but some strains are pathogenic and some of them are zoonotic. Bacterial infection could range in severity from latent infection to active infection depending on their pathogenicity and are affecting millions of individuals worldwide (Mir and Al-baradie, 2013). The common examples of pathogenic bacteria include S. epidermis, Staphylococcus, Bacteriodes, and Enterobacteriaceae. Some bacterial infections acted as the significant public health threat worldwide. Salmonellosis caused by the salmonella enteric subspecies enterica serovar Typhimurium accounts for about 93.8 million cases annually and is associated with death toll up to 150,000 every year. Salmonella typhimurium has been identified as the most common serovar causing nontyphoidal salmonella infection which accounts for about 63.7% in children less than 5 years of age worldwide. Besides salmonellosis, tuberculosis and cholera are also the life-threatening foodborne bacterial infections globally. The major concern in the present times is resistance developed by the pathogenic bacteria against the antibiotics to withstand the adverse effects of drugs, resulting in their efficiency of virulence. The major classes of drugs commonly used for bacterial infections include penicillin, tetracycline, cephalosporins, fluoroquinolones, macrolides, and sulfonamides. In this chapter we will discuss some major bacterial infections, their nature, novel antibacterial targets, and present approach of therapeutics to combat their infection.
Persistent Vibrio-parahaemolyticus-associated vibriosis cases, attributed, in part, to the inefficient techniques for detecting viable-but-non-culturable (VBNC) Vibrio pathogens and the ingestion of undercooked seafood, is the leading cause of bacterial seafood-borne outbreaks, hospitalizations, and deaths in the United States. The effect of extreme heat processing on Vibrio biology and its potential food safety implication has been underexplored. In the present work, environmental samples from the wet market, lagoon, and estuarine environments were analyzed for V. parahaemolyticus recovery using a modified, temperature-dependent, two-step enrichment method followed by culture-based isolation, phenotype, and genotype characterizations. The work recovered novel strains (30% of 12 isolates) of V. parahaemolyticus from prolonged-heat-processing conditions (80 °C, 20 min), as confirmed by 16S rDNA bacterial identification. Select strains, VHT1 and VHT2, were determined to be hemolysis- and urease-positive pathogens. PCR analyses of chromosomal DNA implicated the tdh-independent, tlh-associated hemolysis in these strains. Both strains exhibited significant, diverse antibiotic profiles (p < 0.05). Turbidimetric and viable count assays revealed the pasteurization-resistant V. parahaemolyticus VHT1/VHT2 (62 °C, 8 h). These findings disclose the efficiency of Vibrio extremist recovery by the modified, two-step enrichment technique and improve knowledge of Vibrio biology essential to food safety reformation.
Background
Cholera, an acute diarrheal disease is a major public health problem in many developing countries. Several rapid diagnostic tests (RDT) are available for the detection of cholera, but their efficacies are not compared in an endemic setting. In this study, we have compared the specificity and sensitivity of three RDT kits for the detection of Vibrio cholerae O1 and compared their efficiency with culture and polymerase chain reaction (PCR) methods.
Methods
Five hundred six diarrheal stool samples collected from patients from two different hospitals in Kolkata, India were tested using SD Bioline Cholera, SMART-II Cholera O1 and Crystal-VC RDT kits. All the stool samples were screened for the presence of V . cholerae by direct and enrichment culture methods. Stool DNA-based PCR assay was made to target the cholera toxin ( ctxAB ) and O1 somatic antigen ( rfb ) encoding genes. Statistical evaluation of the RDTs has been made using STATA software with stool culture and PCR results as the gold standards. The Bayesian latent class model (LCM) was used to evaluate the diagnostic tests in the absence of the gold standard.
Results
Involving culture technique as gold standard, the sensitivity and specificity of the cholera RDT kits in the direct testing of stools was highest with SAMRT-II (86.1%) and SD-Cholera (94.4%), respectively. The DNA based PCR assays gave very high sensitivity (98.4%) but the specificity was comparatively low (75.3%). After enrichment, the high sensitivity and specificity was detected with SAMRT-II (78.8%) and SD-Cholera (99.1%), respectively. Considering PCR as the gold standard, the sensitivity and specificity of the RDTs remained between 52.3–58.2% and 92.3–96.8%, respectively. In the LCM, the sensitivity of direct and enrichment testing was high in SAMRT-II (88% and 92%, respectively), but the specificity was high in SD cholera for both the methods (97% and 100%, respectively). The sensitivity/specificity of RDTs and direct culture have also been analyzed considering the age, gender and diarrheal disease severity of the patients.
Conclusion
Overall, the performance of the RDT kits remained almost similar in terms of specificity and sensitivity. Performance of PCR was superior to the antibody-based RDTs. The RTDs are very useful in identifying cholera cases during outbreak/epidemic situations and for making them as a point-of-care (POC) testing tool needs more improvement.
We report two cases of bacteremia caused by non-O1, non-O139 Vibrio cholerae in immunocompetent patients. The first patient presented with fever and watery diarrhea and had traveled recently to Thailand. V. cholerae O24 was detected in the blood and stool. The route of infection was thought to be ingestion of ice containing V. cholerae. The second patient presented with only fever and gave no history of overseas travel. V. cholerae O37 was detected in the blood and bile. Although many cases of V. cholerae infection are imported,V. cholerae is also present in Japanese rivers and can be transmitted domestically. In general, non-O1, non-O 139 V. cholerae causes extraintestinal infections in patients with underlying diseases, and is rarely identified as a cause of bacteremia in immunocompetent patients. Both patients were cholera toxin-negative, El Tor hemolysin-positive, and RTX toxin-positive, suggesting that the latter toxins may be involved in the bacteremia caused by non-O1, non-O139 V. cholerae infection. In both cases, V. cholerae could be identified from the characteristic morphological findings, and it is important to proceed with the identification tests without overlooking the characteristic microbiological findings, regardless of the patientʼs background.
In order to cause disease, pathogenic strains of Vibrio cholerae rely on intricate regulatory networks to orchestrate the transition between their native aquatic environment and the human host. For example, bacteria in a nutrient-starved environment undergo a metabolic shift called the stringent response, which is mediated by the alarmone ppGpp and an RNA-polymerase binding transcriptional factor, DksA. In O1 serogroup strains of V. cholerae, which use the toxin co-regulated pilus (TCP) and cholera toxin (CT) as primary virulence factors, DksA was reported to have additional functions as a mediator of virulence gene expression. However, little is known about the regulatory networks coordinating virulence phenotypes in pathogenic strains that use TCP/CT-independent virulence mechanisms. We therefore investigated whether functions of DksA outside of the stringent response are conserved in type three secretion system (T3SS)-positive V. cholerae . In using the T3SS-positive clinically isolated O39 serogroup strain AM-19226, we observed an increase in dksA expression in the presence of bile at 37 °C. However, DksA was not required for wild-type levels of T3SS structural gene expression, or for colonization in vivo . Rather, data indicate that DksA positively regulates the expression of master regulators in the motility hierarchy. Interestingly, the Δ dksA strain forms a less robust biofilm than the WT parent strain at both 30 and 37 °C. We also found that DksA regulates the expression of hapR , encoding a major regulator of biofilm formation and protease expression. Athough DksA does not appear to modulate T3SS virulence factor expression, its activity is integrated into existing regulatory networks governing virulence-related phenotypes. Strain variations therefore may take advantage of conserved ancestral proteins to expand regulons responding to in vivo signals and thus coordinate multiple phenotypes important for infection.
The human pathogen Vibrio cholerae is the causative agent of severe diarrheal disease known as cholera. Of the more than 200 “O” serogroups of this pathogen, O1 and O139 cause cholera outbreaks and epidemics. The rest of the serogroups, collectively known as non-O1/non-O139 cause sporadic moderate or mild diarrhea and also systemic infections. Pathogenic V. cholerae circulates between nutrient-rich human gut and nutrient-deprived aquatic environment. As an autochthonous bacterium in the environment and as a human pathogen, V. cholerae maintains its survival and proliferation in these two niches. Growth in the gastrointestinal tract involves expression of several genes that provide bacterial resistance against host factors. An intricate regulatory program involving extracellular signaling inputs is also controlling this function. On the other hand, the ability to store carbon as glycogen facilitates bacterial fitness in the aquatic environment. To initiate the infection, V. cholerae must colonize the small intestine after successfully passing through the acid barrier in the stomach and survive in the presence of bile and antimicrobial peptides in the intestinal lumen and mucus, respectively. In V. cholerae, virulence is a multilocus phenomenon with a large functionally associated network. More than 200 proteins have been identified that are functionally linked to the virulence-associated genes of the pathogen. Several of these genes have a role to play in virulence and/or in functions that have importance in the human host or the environment. A total of 524 genes are differentially expressed in classical and El Tor strains, the two biotypes of V. cholerae serogroup O1. Within the host, many immune and biological factors are able to induce genes that are responsible for survival, colonization, and virulence. The innate host immune response to V. cholerae infection includes activation of several immune protein complexes, receptor-mediated signaling pathways, and other bactericidal proteins. This article presents an overview of regulation of important virulence factors in V. cholerae and host response in the context of pathogenesis.
This book, originally published in 2004, is concerned with the links between human evolution and infectious disease. It has long been recognised that an important factor in human evolution has been the struggle against infectious disease and, more recently, it was revealed that complex genetic polymorphisms are the direct result of that struggle. As molecular biological techniques become more sophisticated, a number of breakthroughs in the area of host-pathogen evolution led to an increased interest in this field. From the historical beginnings of J. B. S. Haldane's original hypothesis to more recent research, this book strives to evaluate infectious diseases from an evolutionary perspective. It provides a survey of information regarding host-pathogen evolution related to major infectious diseases and parasitic infections, including malaria, influenza and leishmaniasis. Written by leading authorities in the field, and edited by a former pupil of Haldane, Infectious Disease and Host-Pathogen Evolution will be valuable for those working in related areas of microbiology, parasitology, immunology and infectious disease medicine, as well as genetics, evolutionary biology and epidemiology.
It has been well known that Vibrio cholerae inhabit in environmental water. As many patients infected with cholera toxin-producing V. cholerae O1 (toxigenic V. cholerae O1) emerge in Kolkata, India, it has been thought that toxigenic V. cholerae O1 is easily detected in environmental water in Kolkata. However, we could not isolate toxigenic V. cholerae O1 from environmental water in Kolkata, though NAG Vibrio (generic name of V. cholerae non-O1/non-O139) is constantly detected. To clear the reason for the non-isolation of toxigenic V. cholerae O1, we examined the viability of V. cholera O1 and NAG Vibrios in the artificial low ionic strength aquatic solution. We found that the viability of toxigenic V. cholerae O1 in the solution is low, but that of NAG Vibrios is high. Subsequently, we examined the viability of NAG Vibrios possessing cholera toxin gene (ctx) in the same condition and found that the viability of these NAG Vibrios is low. These results indicate that the existence of ctx in V. cholerae affects the viability of V. cholerae in the aquatic solution used in this experiment. We thought that there was closely relation between the low viability of toxigenic V. cholerae O1 in the artificial low ionic strength aquatic solution and the low frequency of isolation of the strain from environmental water.
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Non‐O1/non‐O139 nontoxigenic Vibrio cholerae associated with cholera‐like diarrhea has been reported in Kolkata, India. However, the property involved in the pathogenicity of these strains has remained unclear. We examined the character of 25 non‐O1/non‐O139 nontoxigenic V. cholerae isolated during 8 years from 2007 to 2014 in Kolkata. Determination of serogroup showed that the serogroups O6, O10, O35, O36, O39, and O70 were represented by two strains in each serogroup, and the remaining isolates belonged to different serogroups. To clear the character of antibiotic resistance of these isolates, the antibiotic resistance test and the gene analysis were performed. According to antimicrobial drug susceptibility testing, 13 strains were classified as drug resistant. Among them, 10 strains were quinolone resistant and 6 of 13 strains were resistance against more than 3 antibiotics. To define the genetic background of the antibiotic character of these strains, we determined whole‐genome sequences of these strains. From the analysis of these sequences, it becomes clear that all of quinolone resistance isolates have mutations in quinolone resistance‐determining regions. Further search on the genome sequence showed that 4 strains possess class 1 integrons in their genomes, and that three of four integrons are found to be located in their genomic islands. These genomic islands are novel type. This indicates that various integrons containing drug resistance genes are spreading among V. cholerae non‐O1/non‐O139 strains through the action of newly‐generated genomic islands.
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Multilocus enzyme electrophoresis (MLEE) of 397 Vibrio cholerae isolates, including 143 serogroup reference strains and 244 strains from Mexico and Guatemala, identified 279 electrophoretic types (ETs) distributed in two major divisions (I and II). Linkage disequilibrium was demonstrated in both divisions and in subdivision Ic of division I but not in subdivision Ia, which includes 76% of the ETs. Despite this evidence of relatively frequent recombination, clonal lineages may persist for periods of time measured in at least decades. In addition to the pandemic clones of serogroups O1 and O139, which form a tight cluster of four ETs in subdivision Ia, MLEE analysis identified numerous apparent clonal lineages of non-O1 strains with intercontinental distributions. A clone of serogroup O37 that demonstrated epidemic potential in the 1960s is closely related to the pandemic O1/O139 clones, but the nontoxigenic O1 Inaba El Tor reference strain is not. A strain of serogroup O22, which has been identified as the most likely donor of exogenous rfb region DNA to the O1 progenitor of the O139 clone, is distantly related to the O1/O139 clones. The close evolutionary relationships of the O1, O139, and O37 epidemic clones indicates that new cholera clones are likely to arise by the modification of a lineage that is already epidemic or is closely related to such a clone.
Cholera caused by the toxigenic Vibrio cholerae is still a major public health problem in many countries. This disease is mainly due to poor sanitation, hygiene and consumption of unsafe water. Several recent epidemics of cholera showed its increasing intensity, duration and severity of the illness. This indicates an urgent need for effective management and preventive measures in controlling the outbreaks and epidemics. In preventing and spread of epidemic cholera, rapid diagnostic tests (RDTs) are useful in screening suspected stool specimens, water/food samples. Several RDTs developed recently are considered as investigative tools in confirming cholera cases, as the culture techniques are difficult to establish and/or maintain. The usefulness of RDTs will be more at the point-of-care facilities as it helps to make appropriate decisions in the management of outbreaks or epidemiological surveillance by the public health authorities. Apart from RDTs, several other tests are available for the direct detection of either V. cholerae or its cholera toxin. Viable but non-culturable (VBNC) state of V. cholerae poses a great challenge in developing RDTs. The aim of this article is to provide an overview of current knowledge about RDT and other techniques with reference to their status and future potentials in detecting cholera/V. cholerae.
The O-polysaccharide (O-antigen, OPS) of Vibrio cholerae O68 was studied using chemical analyses and 1D and 2D NMR spectroscopy. The following structure of the tetrasaccharide repeating unit of the OPS was established:
where Dhpa indicates (2S,4R)-2,4-dihydroxypentanoic acid existing mainly in the form of 1,4-lactone. Recently, (2R,4S)- and (2R,4R)-isomers of Dhpa have been found in the OPS of Providencia alcalifaciens O8 and O31, respectively. Functions of genes in the O-antigen gene cluster of Vibrio cholerae O68 were predicted according to the OPS structure established. These data provide a molecular basis for classification of V. cholerae strains.
Vibrio cholerae O1 infections mainly are responsible for significant mortality and morbidity amongst children, however, non-O1/non-O139 V. cholerae have also been reported to cause mild to severe infections because of their virulence potential. The pathogenic mechanisms of non-O1, non-O139 isolates are not as clearly understood as for that of O1 and O139 isolates. Type three secretion system (TTSS) is also considered one of the important virulent factors and during the current study, we investigated the role of TTSS in association with non-O1/non-O139 clinical isolates. We report that the presence of TTSS in non-O1/non-O139 V. cholerae clinical isolate (D13) from a child confers more virulence compared to the one lacking it (D15) in another clinical case during the small cholera epidemic. Moreover, the antibiotic susceptibility profiles of D13 and D15 indicate that they are multiple drug resistance (MDR) isolates. The sequence analysis for TTSS cluster was carried out for D13 and compared with the TTSS positive reference Vibrio parahaemolyticus RIMD2210633 and V. cholerae AM19226 non-O1/non-O139. Furthermore, the pathogenic potential of D13 & D15 was also explored in simple and economical invertebrate host model, Galleria mellonella and the results revealed that TTSS+ve isolate (D13) was more virulent compared to TTSS-ve isolate (D15). We suggest that this distinct genetic difference, seen in natural variants D13 and D15, is also reflected by the clinical picture of the former in contributing towards the severity of disease symptoms and this finding was further validated by assessing virulence potential of both isolates using inexpensive G. mellonella infection model.
A loop-mediated isothermal amplification assay was developed. It was designed for recognizing Vibrio cholerae O1/O139, where atpA, rfbN, and wfbR genes were adopted. The assay specifically detected the target with sensitivities of 5-67 copies per reaction in 1 h. The assay will aid rapid detection of the cholera bacterium.
Cholera is one of the most important epidemic diseases globally. It is causing of
morbidity and mortality in the world. Severe watery diarrhea causes a composite process
involving several component that help them reach the lining of the small intestine, form colonies
and generate bacterial toxins. This survey was carried out to discover the genetic patterns of
clinical isolates according to the presence or absence of toxic genes for the city of Diwaniyah in
southern Iraq. Sixty isolates were isolated from patients with cholera. The isolates included the
center of the city and the surrounding rural areas. Biochemical and serological diagnosis. All
the isolates were V. cholera serogroup O 1 of the serotyping Ogawa in biotype El Tor. Genetic
testing was carried out using PCR technique and base on the presence or absence of toxin genes.
Three genotypes were identified for the region.
Vibrio cholerae inhabits aquatic environments worldwide and has over 200 recognized serogroups classified by O-polysaccharide specificity. Here, we report that V. cholerae selects either of two genetic traits during their evolution. Sequencing of the specific gene locus MS6_A0927 revealed that 339 of 341 strains of V. cholerae and closely related Vibrio species originating from 34 countries over a century carried either metY (M) (~1,269 bp) or luxR-hchA (LH) (~1,600 bp) genes, and consequently those vibrios were separated into two clusters, M (45.4%) and LH (54.6%). Only two strains contained both M and LH in the same locus. Moreover, extensive polymorphisms in those genes were detected in M and LH with 79 and 46 sequence variations, respectively. V. cholerae O1 strains isolated from cholera outbreaks worldwide, and some non-O1 strains evolving from O1 via exchange of genes encoding cell surface polysaccharides possessed LH alleles. Analysis of polymorphisms in the gene locus implicated a high degree of genetic diversity and identical subpopulations among the V. cholerae species.
In February 1994, an outbreak of diarrhea caused by non-O1 Vibrio cholerae occurred among volunteers in a vaccine trial study area in Lima, Peru. Clinically, 95% of the patients presented with liquid diarrhea with either no or mild dehydration. Serogrouping of 58 isolates recovered from diarrheal patients affected in the outbreak revealed seven different serogroups, with serogroups O10 (21%) and O12 (65%) being predominant. Most of these isolates were susceptible to a variety of antimicrobial agents. None of the 58 isolates hybridized with a DNA probe previously used to detect the gene encoding the heat-stable enterotoxin NAG-ST or produced cholera toxin as assessed by GM1 ganglioside enzyme-linked immunosorbent assay. Ribotyping exhibited 10 different BglI ribotype patterns among the 58 V. cholera non-O1 strains studied. However, ribotyping showed that all isolates belonging to serogroup O12 exhibited identical ribotypes and that 83% of the serogroup O10 isolates belonged to another identical ribotype, thus showing excellent correlation between ribotypes and serogroups. Among a group of O10 and O12 isolates selected for virulence studies, none produced enterotoxin whereas the majority produced a cytotoxin, as assessed in Y1 and HeLa cells. These isolates were also negative for the gene encoding zonula occludens toxin (Zot) as assessed by a PCR assay. The isolates tested showed strong adherence and some degree of invasion in the HEp-2 cell assay, whereas none of the isolates was positive in the PCR assay for the gene encoding the toxin coregulated pilus subunit A antigen (tcpA). In the removable intestinal tie adult rabbit diarrhea model, O10 and O12 serogroup isolates produced severe diarrhea and occasionally death when rabbits were challenged with 10(10) bacterial cells. Fluid accumulation was shown in the rabbit intestinal loop test when whole cultures were injected. No significant difference in virulence was shown between serogroup O10 and O12 isolates. This study provides further evidence that V. chlorae non-O1 non-O139 strains have diarrhegenic potential for humans through a yet-undefined mechanism(s) and that such strains can cause outbreaks.
Fifty-seven new O serogroups have been added to the existing serotyping scheme ofVibrio cholerae to extend the scheme from O84 to O140. Prominent new additions were serogroups O139 and O140. The reference strain of O139 was isolated from a patient from an epidemic of cholera-like diarrhea in Madras, Southern India. Serogroup O140 was assigned to a group ofV. cholerae strains which were tentatively named as the Hakata serogroup and which possessed the C (Inaba) factor but not the B (Ogawa) nor the A (major specific antigen of O1 serogroup ofV. cholerae). As all antisera against reference strains ofV. cholerae contained some amount of antibody to the rough (R) antigen, all diagnostic O antisera must be absorbed with the reference rough strain, CA385.
Sixty-six strains unable to ferment sucrose and resemblingVibrio mimicus andV. cholerae were submitted to an extensive phenotypic characterization. DNA-DNA homology among selected strains and the type strain ofV. cholerae was studied by the S1 endonuclease method. Seven sucrose-negative strains were shown to have the phenotypic properties of and a high percentage DNA relatedness toV. cholerae and a low level of homology withV. mimicus. Eight luminescent strains phenotypically most closely resembledV. mimicus; however, two of these were shown to have a high level of DNA homology withV. cholerae and a low level of relatedness toV. mimicus. A single strain was found to be phenotypically and genetically unrelated to eitherV. cholerae orV. mimicus and may represent a new species. The remaining strains were phenotypically shown to beV. mimicus, and selected strains were shown to have a high percentage DNA homology withV. mimicus and a low level of homology withV. cholerae. Problems associated with the identification of these strains and differential traits are discussed.
Two strains (O22 reference strain, 169–68, and strain 490–93 isolated from a patient with diarrhea in Thailand) ofVibrio cholerae non-O1 possessing somatic (O) antigen factors in common withV. cholerae O139 synonym Bengal are described. The O antigens of these two strains were closely related to that ofV. cholerae O139 in an a,b-a,c type of relationship, but were not completely identical with serogroup O139. Therefore, both these strains are not classified into the O139 serogroup ofV. cholerae, because they have their own major antigens. As the strain 490–93 could not be placed into any of the 154 established O serogroups ofV. cholerae, this strain was assigned to a new serogroup, O155. For practical use, the diagnostic antiserum prepared against the O139 reference strain (MO45, ATCC 51394) ofV. cholerae must be absorbed with reference strains 169–68 and 490–93 representing serogroups O22 and O155 ofV. cholerae to remove cross-reacting agglutinins of the O22 and O155 strains, respectively.
The name Yokenella gen. nov. is proposed for a group of organisms in the family Enterobacteriaceae isolated from clinical sources and insects. Yokenella is a gram-negative, oxidase-negative, fermentative, motile rod possessing the characteristics of the family Enterobacteriaceae and the guanine plus cytosine contents of the DNA range from 58.0 to 59.3 mol%. Biochemical characteristics of this group and DNA hybridization studies indicate that the 11 strains studied here comprise a separate species which should be best placed in a new genus. This single DNA hybridization group is named Yokenella regensburgei sp. nov. The type strain of Y. regensburgei is NIH 725-83 (JCM 2403).
Vibrio species as causative agents of food-borne infection Developments in food microbiology
- R Sakazaki
- T Shimada