[Show abstract][Hide abstract] ABSTRACT: Antibiotics that are excreted into the intestinal tract may disrupt the indigenous intestinal microbiota and promote colonization by healthcare-associated pathogens. ß-lactam, or penicillin-type antibiotics, are among the most widely utilized antibiotics worldwide, and may also adversely affect the microbiota. Many bacteria are capable, however, of producing ß-lactamase enzymes that inactivate ß-lactam antibiotics. We hypothesized that prior establishment of intestinal colonization with a ß-lactamase-producing anaerobe might prevent these adverse effects of ß-lactam antibiotics, by inactivating the portion of antibiotic that is excreted into the intestinal tract. Here, mice with a previously abolished microbiota received either oral normal saline or an oral cephalosporinase-producing Bacteroides thetaiotomicron for 3 days. Mice then received 3 days of subcutaneous ceftriaxone, followed by either 1) oral administration of vancomycin-resistant Enterococcus (VRE) or 2) sacrifice and assessment of in vitro growth of epidemic and nonepidemic strains of C. difficile in murine cecal contents. Stool concentrations of VRE and ceftriaxone were measured, cecal levels of C. difficile 24 hours after incubation were quantified, and denaturing gradient gel electrophoresis (DGGE) of microbial 16S rRNA genes was performed to evaluate antibiotic effect on the microbiota. The results demonstrated that establishment of prior colonization with a ß-lactamase-producing intestinal anaerobe inactivated intra-intestinal ceftriaxone during treatment with this antibiotic, allowed recovery of the normal microbiota despite systemic ceftriaxone, and prevented overgrowth with VRE and epidemic and nonepidemic strains of C. difficile in mice. These findings describe a novel probiotic strategy to potentially prevent pathogen colonization in hospitalized patients.
[Show abstract][Hide abstract] ABSTRACT: An understanding of the impact of antibiotics on the intestinal reservoir of KPC carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) is important to prevent its emergence. We used a mouse model to examine the effect of antibiotic treatment on the
establishment and elimination of intestinal colonization with KPC-Kp. Mice (10 per group) received subcutaneous antibiotics
daily for 8 days. On day 3 of treatment, 103 CFU of KPC-Kp was given orogastrically, and concentrations of KPC-Kp in stool were monitored. Additional experiments assessed
the effects of antibiotic treatment on concentrations of total anaerobes and Bacteroides spp. in stool and the efficacy of orogastric gentamicin and polymyxin E in suppressing KPC-Kp colonization. Of four antibiotics
with minimal activity against the KPC-Kp test strain (MIC ≥ 16 μg/ml), those that suppressed total anaerobes and bacteroides
(i.e., clindamycin and piperacillin-tazobactam) promoted colonization by KPC-Kp (P < 0.001), whereas agents that did not suppress total anaerobes or bacteroides (i.e., ciprofloxacin and cefepime) did not
(P = 0.35). Of two agents with moderate activity against the KPC-Kp test strain, ertapenem (MIC, 4 μg/ml) did not promote colonization
by KPC-Kp, whereas tigecycline (MIC, 3 μg/ml) did (P < 0.001), despite not reducing levels of total anaerobes or bacteroides. Orogastric treatment with gentamicin and polymyxin
E suppressed KPC-Kp to undetectable levels in the majority of mice. These data suggest that antibiotics that disturb the intestinal
anaerobic microflora and lack significant activity against KPC-Kp promote colonization by this organism. The administration
of nonabsorbed oral antibiotics may be an effective strategy to suppress colonization with KPC-Kp.
[Show abstract][Hide abstract] ABSTRACT: Tigecycline is a broad-spectrum glycylcycline antibiotic with potent in vitro activity against Clostridium difficile. We used a mouse model to test the hypothesis that tigecycline has a low propensity to promote colonization and toxin production
by C. difficile due to inhibitory activity in the colon. Mice (5 to 8 per group) received subcutaneous injections of tigecycline (low and
high doses) alone or in combination with clindamycin for 6 days. Growth of and toxin production by 3 strains of C. difficile (tigecycline MICs ≤ 0.012 μg/ml) were measured in cecal contents collected 6 h or 3 days after the final antibiotic dose.
Antibiotic concentrations were measured using a bioassay, and concentrations of total anaerobes and Bacteroides spp. were measured. The effects of tigecycline on rendering mice susceptible to colonization with and reducing the burden
of C. difficile were also examined. In comparison to saline controls, clindamycin promoted the growth of C. difficile (P < 0.001) in cecal contents, whereas tigecycline did not. Tigecycline did not suppress total anaerobes or Bacteroides spp. in comparison to saline controls. Concurrent administration of tigecycline prevented clindamycin-induced promotion of
C. difficile in cecal contents collected 6 h or 3 days (high dose only) after the final antibiotic dose. Tigecycline did not promote the
establishment of colonization in mice, yet it did not reduce concentrations of C. difficile in animals with established colonization. In summary, tigecycline did not promote the growth of or toxin production by C. difficile, probably due to inhibitory activity against C. difficile and relative sparing of indigenous anaerobic microflora.
[Show abstract][Hide abstract] ABSTRACT: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe, rapid, and automated.
The Tru-D Rapid Room Disinfection device is a mobile, fully-automated room decontamination technology that utilizes ultraviolet-C irradiation to kill pathogens. We examined the efficacy of environmental disinfection using the Tru-D device in the laboratory and in rooms of hospitalized patients. Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected from commonly touched surfaces before and after use of Tru-D.
On inoculated surfaces, application of Tru-D at a reflected dose of 22,000 microWs/cm(2) for approximately 45 minutes consistently reduced recovery of C. difficile spores and MRSA by >2-3 log10 colony forming units (CFU)/cm2 and of VRE by >3-4 log10 CFU/cm(2). Similar killing of MRSA and VRE was achieved in approximately 20 minutes at a reflected dose of 12,000 microWs/cm(2), but killing of C. difficile spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of C. difficile cultures by 80%. After routine hospital cleaning of the rooms of MRSA carriers, 18% of sites under the edges of bedside tables (i.e., a frequently touched site not easily amenable to manual application of disinfectant) were contaminated with MRSA, versus 0% after Tru-D (P < 0.001). The system required <5 minutes to set up and did not require continuous monitoring.
The Tru-D Rapid Room Disinfection device is a novel, automated, and efficient environmental disinfection technology that significantly reduces C. difficile, VRE and MRSA contamination on commonly touched hospital surfaces.
[Show abstract][Hide abstract] ABSTRACT: To determine whether a multihospital Clostridium difficile outbreak was associated with epidemic strains and whether use of particular fluoroquinolones was associated with increased infection rates, we cultured feces from C. difficile-infected patients. Use of fluoroquionolones with enhanced antianaerobic activity was not associated with increased infection rates.
[Show abstract][Hide abstract] ABSTRACT: Background: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. Several studies have demonstrated that cleaning of surfaces in healthcare facilities is often suboptimal. There is a need for new disinfection methods that are effective but also safe, rapid, and automated. The Tru-DTM Rapid Room Disinfection device is a mobile, fully-automated room decontamination technology that utilizes ultraviolet-C irradiation to kill pathogens.
Objective: To examine the efficacy of Tru-D disinfection verses standard housekeeping disinfection on commonly-touched surfaces and surfaces not easily amenable to manual application of disinfectant in rooms of hospitalized patients and on portable medical equipment.
Methods: Cultures for C. difficile and methicillin-resistant Staphylococcus aureus (MRSA) were collected from commonly-touched surfaces in rooms and on portable medical equipment before and after use of the Tru-D device (reflective dose, 22,000 µWs/cm2 for ~45 minutes). Staphylococcus warneri was planted on portable medical equipment and under the edges of bedside tables (i.e., a frequently touched site not easily amenable to manual application of disinfectant) and cultures were collected before and after Tru-D disinfection (reflective dose of 12,000 µWs/cm2 for ~ 20 minutes) or standard house-keeping disinfection.
Results: Disinfection of hospital rooms with Tru-D reduced the frequency of positive C. difficile cultures by 83%. No cultures of portable equipment were positive for C. difficile. However, S. warneri planted on portable medical equipment was reduced by ~ 2.0 logs on sites that may be missed by standard housekeeping cleaning (i.e. inside of handles, rolled up pressure cuffs, and the inside edges of equipment). In hospital rooms, an average of 3.5 logs of planted S. warneri remained under each bedside table after routine hospital cleaning versus 0.8 logs per site after Tru-D disinfection (P = 0.06). After routine hospital cleaning, 18% of sites under the edges of bedside tables were contaminated with MRSA versus 0% after Tru-D disinfection (P <0.001).
Conclusions: The Tru-D Rapid Room Sterilization device is a novel, automated, and efficient environmental disinfection technology that significantly reduces C. difficile and Staphylococcus spp. contamination on commonly touched hospital surfaces. The Tru-D device reduces contamination levels on surfaces not easily amenable to standard housekeeping disinfection.
Fifth Decennial International Conference on Health-Care Related Infections 2010; 03/2010
[Show abstract][Hide abstract] ABSTRACT: Background: Environmental surfaces play an important role in transmission of healthcare-associated pathogens. There is a need for new disinfection methods that are effective against Clostridium difficile spores, but also safe and rapid. The SterilrayTM Disinfection Wand device is a hand-held room decontamination technology that utilizes far-ultraviolet irradiation (190-220nm) to kill pathogens.
Objective: To examine the efficacy of environmental disinfection using the Sterilray device in the laboratory and in rooms of hospitalized patients.
Methods: Cultures for C. difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) were collected before and after use of the Sterilray device from inoculated surfaces in the laboratory and from commonly-touched surfaces in rooms of hospitalized patients.
Results: On inoculated surfaces in the laboratory, application of the Sterilray device at a radiant dose of 100 mj/cm2 for ~ 5 seconds consistently reduced recovery of C. difficile spores by >3-4 logs, MRSA by >4-5 logs and of VRE by >6-7 logs. A >3 log reduction of MRSA and VRE was achieved in ~2 seconds at a lower radiant dose, but killing of C. difficile spores was significantly reduced. However, the presence of organic material significantly reduced the lethal effect of the far-ultraviolet radiation. In hospital rooms that were not pre-cleaned, disinfection with the Sterilray device reduced the frequency of positive C. difficile cultures by 61%, MRSA cultures by 41% and VRE cultures by 58%. On gloved hands contaminated with C. difficile spores, disinfection with a radiant dose of 100 mj/cm2 for ~ 5 seconds reduced transfer of spores by 3 logs.
Conclusions: The SterilrayTM Disinfection Wand is a novel environmental disinfection technology that rapidly kills C. difficile spores and other healthcare-associated pathogens on surfaces and on gloved hands. However, the presence of organic matter decreases the efficacy of the far-ultraviolet radiation, possibly explaining the more modest results observed on surfaces in hospital rooms that were not pre-cleaned.
Fifth Decennial International Conference on Health-Care Related Infections 2010; 03/2010
[Show abstract][Hide abstract] ABSTRACT: Background: A 1:10 dilution of household bleach (sodium hypochlorite) is commonly used in hospitals for decontamination of surfaces in rooms of patients with Clostridium difficile infection (CDI). However, bleach has several limitations, including corrosive effects on various materials, irritation of eyes and respiratory tracts of cleaning staff and patients, and requirement for up to 10 minutes of contact time to achieve optimal killing of C. difficile spores.
Objective: To compare the sporicidal activity and materials compatibility of a new 0.0175% peracetic acid-based disinfectant (Surface Sporicidal Disinfectant or SSD) versus a 1:10 dilution of household bleach.
Methods: To compare the in vitro activity of the disinfectants, reductions in viable spore counts of 3 strains of C. difficile were monitored after timed exposures to the disinfectants. To assess materials compatibility, the disinfectants were applied daily to several common hospital surfaces (e.g., bedrail, telephone, chair, privacy curtain, and call button), metals, polyurethane, and polycarbonate and effects were monitored over time.
Results: Both SSD and bleach reduced recovery of spores by >4 log10 colony-forming units in a time-dependent fashion; however, SSD resulted in significantly more rapid killing of spores (P <0.01) (Figure) and its activity was less susceptible to inactivation by organic material. Daily application of 1:10 bleach resulted in fading of the hospital privacy curtains and chair, whereas SSD did not. Housekeeping staff using SSD reported no respiratory or eye irritation.
Conclusions: In comparison to bleach, SSD killed C. difficile spores more rapidly, was less susceptible to inactivation by organic matter, and caused less fading of hospital curtains and chairs. Further studies are needed to assess the use of SSD in rooms of patients with CDI.
Fifth Decennial International Conference on Health-Care Related Infections 2010; 03/2010
[Show abstract][Hide abstract] ABSTRACT: Proton pump inhibitors (PPIs) have been associated with Clostridium difficile infection (CDI) in several recent studies. However, other studies have not shown this association, and the mechanism by which
PPIs might promote CDI has not been elucidated. We hypothesized two possible mechanisms of causation: first, by raising pH,
PPIs may prevent gastric contents from killing C. difficile spores; second, gastric contents of PPI-treated patients may promote germination and outgrowth of C. difficile spores. Survival rates of spores from six different strains of C. difficile in acidic gastric contents were assessed using quantitative cultures on selective media. Germination and outgrowth of spores
were assessed by heat shock at 80°C, phase-contrast microscopy, and ethanol shock after incubation for 24 h in the gastric
contents of patients and in the gastric, small intestinal, and cecal contents of mice. C. difficile spores survived and remained dormant in nonbilious gastric contents with acidic pH. Germination did not occur in unmodified
gastric contents of patients but did occur with the addition of taurocholic acid and amino acids. In mice, germination did
not occur in gastric contents but did occur in small intestinal and cecal contents. In summary, C. difficile spores survived in acidic gastric contents and did not undergo germination and outgrowth in gastric contents, probably due
to lack of essential germinants, such as taurocholic acid. Our results suggest that the effects of PPIs in the stomach do
not contribute to the pathogenesis of CDI.
[Show abstract][Hide abstract] ABSTRACT: Healthy infants frequently acquire Staphylococcus aureus colonization; however, the modes of transmission are not well defined. In this study, 8 of 23 (35%) infants cultured at age 2 weeks acquired S aureus carriage, but only 1 infant had a family member with nasal carriage of the same clone, suggesting that sources other than colonized family members may account for a significant proportion of cases.
American journal of infection control 04/2009; 37(7):598-600. DOI:10.1016/j.ajic.2008.12.003 · 2.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a culture survey, we found that 42% of hospital privacy curtains were contaminated with vancomycin-resistant enterococci, 22% with ethicillin-resistant Staphylococcus aureus, and 4% with Clostridium difficile. Hand imprint cultures demonstrated that these pathogens were easily acquired on hands. Hospital curtains are a potential source for dissemination of healthcare-associated pathogens.
Infection Control and Hospital Epidemiology 10/2008; 29(11):1074-6. DOI:10.1086/591863 · 4.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: For treatment of mild to moderate Clostridium difficile-associated disease (CDAD), oral metronidazole has been recommended as the preferred agent, in part due to concern that vancomycin
may be more likely to promote colonization by vancomycin-resistant enterococci (VRE). We performed a prospective observational
study to examine the effects of oral metronidazole or vancomycin treatment of CDAD on acquisition and concentration of VRE
stool colonization. Before, during, and after 90 courses of CDAD therapy, stool samples were cultured for VRE, and the concentrations
were quantified. Eighty-seven subjects (97%) had received antibiotics within the past month. For 56 treatment courses in which
preexisting VRE colonization was present, metronidazole (n = 37 courses) and vancomycin (n = 19 courses), each promoted persistent VRE overgrowth during therapy, and the concentration decreased significantly in both
groups by ∼2 weeks after completion of treatment (P <0.049). For 34 treatment courses in which baseline cultures were negative for VRE, new detection of VRE stool colonization
occurred during 3 (14%) of the 22 courses of metronidazole and 1 (8%) of the 12 courses of vancomycin (P = 1.0). These results demonstrate that both oral metronidazole and oral vancomycin promote the overgrowth of VRE during treatment
of CDAD. New CDAD treatments are needed that are less likely to disrupt the intestinal microflora and promote overgrowth of
[Show abstract][Hide abstract] ABSTRACT: After mice received orogastric administration of a fluoroquinolone-resistant Klebsiella pneumoniae strain, subcutaneous treatment with ciprofloxacin, levofloxacin, and moxifloxacin promoted persistent low-density colonization in 10% to 40% of the mice, whereas treatment with clindamycin consistently promoted high-density colonization. No emergence of fluoroquinolone-resistant gram-negative bacilli was detected in the mice during or after treatment with the fluoroquinolone antimicrobial agents.
[Show abstract][Hide abstract] ABSTRACT: Proton pump inhibitors (PPIs) have been identified as a risk factor for Clostridium difficile-associated diarrhea (CDAD), though the mechanism is unclear because gastric acid does not kill C. difficile spores. We hypothesized that the vegetative form of C. difficile, which is killed by acid, could contribute to disease pathogenesis if it survives in room air and in gastric contents with
elevated pH. We compared the numbers of C. difficile spores and vegetative cells in stools of patients prior to and during the treatment of CDAD. We assessed the survival of
vegetative cells on moist or dry surfaces in room air versus anaerobic conditions and in human gastric contents, in pH-adjusted
gastric contents, and in gastric contents from individuals receiving PPI therapy. Stool samples obtained from patients prior
to the initiation of antibiotic treatment for C. difficile contained ∼10-fold more vegetative cells than spores. On dry surfaces, vegetative C. difficile cells died rapidly, whereas they remained viable for up to 6 h on moist surfaces in room air. Vegetative C. difficile cells had only marginal survival in gastric contents at low pH; adjustment to a pH of >5 resulted in survival similar to
that in the phosphate-buffered saline control. The survival of vegetative C. difficile in gastric contents obtained from patients receiving PPIs was also increased at a pH of >5. The ability of the vegetative
form of C. difficile to survive on moist surfaces and in gastric contents with an elevated pH suggests a potential mechanism by which PPI therapy
could increase the risk of acquiring C. difficile.
[Show abstract][Hide abstract] ABSTRACT: Exposure to pH 1 or 2 buffers or acidic gastric contents resulted in the killing of vancomycin-resistant Enterococcus sp., Klebsiella pneumoniae, Staphylococcus aureus, and Candida glabrata but not Clostridium difficile spores. Nitrite enhanced killing under acidic conditions, but significant killing of C. difficile spores required nitrite concentrations above usual physiological levels.