Clostridium difficile infection is the leading cause of health care-associated diarrhea, and the bacterium can also be carried asymptomatically. The objective of this study was to identify host and ...bacterial factors associated with health care-associated acquisition of C. difficile infection and colonization.
We conducted a 15-month prospective study in six Canadian hospitals in Quebec and Ontario. Demographic information, known risk factors, potential confounding factors, and weekly stool samples or rectal swabs were collected. Pulsed-field gel electrophoresis (PFGE) was performed on C. difficile isolates to determine the genotype. Levels of serum antibodies against C. difficile toxins A and B were measured.
A total of 4143 patients were included in the study; 117 (2.8%) and 123 (3.0%) had health care-associated C. difficile infection and colonization, respectively. Older age and use of antibiotics and proton-pump inhibitors were significantly associated with health care-associated C. difficile infection. Hospitalization in the previous 2 months; use of chemotherapy, proton-pump inhibitors, and H(2) blockers; and antibodies against toxin B were associated with health care-associated C. difficile colonization. Among patients with health care-associated C. difficile infection and those with colonization, 62.7% and 36.1%, respectively, had the North American PFGE type 1 (NAP1) strain.
In this study, health care-associated C. difficile infection and colonization were differentially associated with defined host and pathogen variables. The NAP1 strain was predominant among patients with C. difficile infection, whereas asymptomatic patients were more likely to be colonized with other strains. (Funded by the Consortium de Recherche sur le Clostridium difficile.).
Using whole genome sequencing of isolates from a cohort of patients with Clostridium difficile infection (CDI) and colonization, we found that incident CDI cases were more likely to be linked to an ...infected than colonized donor.
Abstract
Background
Whole genome sequencing (WGS) studies can enhance our understanding of the role of patients with asymptomatic Clostridium difficile colonization in transmission.
Methods
Isolates obtained from patients with Clostridium difficile infection (CDI) and colonization identified in a study conducted during 2006-2007 at 6 Canadian hospitals underwent typing by pulsed-field gel electrophoresis, multilocus sequence typing, and WGS. Isolates from incident CDI cases not in the initial study were also sequenced where possible. Ward movement and typing data were combined to identify plausible donors for each CDI case, as defined by shared time and space within predefined limits. Proportions of plausible donors for CDI cases that were colonized, infected, or both were examined.
Results
Five hundred fifty-four isolates were sequenced successfully, 353 from colonized patients and 201 from CDI cases. The NAP1/027/ST1 strain was the most common strain, found in 124 (62%) of infected and 92 (26%) of colonized patients. A donor with a plausible ward link was found for 81 CDI cases (40%) using WGS with a threshold of ≤2 single nucleotide polymorphisms to determine relatedness. Sixty-five (32%) CDI cases could be linked to both infected and colonized donors. Exclusive linkages to infected and colonized donors were found for 28 (14%) and 12 (6%) CDI cases, respectively.
Conclusions
Colonized patients contribute to transmission, but CDI cases are more likely linked to other infected patients than colonized patients in this cohort with high rates of the NAP1/027/ST1 strain, highlighting the importance of local prevalence of virulent strains in determining transmission dynamics.
Molecular methods to detect diarrheal pathogens are increasingly being used in place of conventional methods. We compared a new multiplex real-time PCR assay for detection of both bacterial and viral ...gastroenteritis agents, the Allplex™ Gastrointestinal Panel Assays (AGPA), to conventional methods (stool culture for bacterial pathogens and electron microscopy (EM) for viral pathogens).
Gastrointestinal viruses, in particular norovirus genogroup II viruses, were detected by the AGPA in a high number of specimens that were negative by EM. For bacterial pathogens, the AGPA was able to detect the organisms grown in culture with high sensitivity and additionally detected several types of E. coli, such as enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), and non-O157 Shiga toxin-producing E. coli (STEC), that could not be detected with conventional culture methods. Overall, the AGPA had a > 2-fold higher detection rate than the conventional methods, with 24/135 (17.8%) samples positive by conventional methods and 60/135 (44.4%) by AGPA. Thus, diarrhea pathogen detection rates increased substantially with the use of the AGPA as compared to conventional methods.
The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on ...anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of infections caused by anaerobic organisms.
•Susceptibility profiles of anaerobes encountered in Ontario were determined.•1.2% of B. fragilis were resistant to metronidazole.•12.1% of Fusobacterium species were resistant to penicillin.•Resistance rates in this study were lower than rates reported in the literature.
Highlights • PCP infection can occur late after renal transplant, despite initial post-transplant prophylaxis. • Reduced renal function and lymphopenia are likely risk factors for PCP infection in ...RTR's. • Ambulatory care clinics and phlebotomy labs are potential site for human-to-human transmission of PCP. • Respiratory infection control measures should be a priority in ambulatory health care settings to prevent PCP outbreaks.
Klebsiella pneumoniae isolates from three patients admitted to the Ottawa Hospital, a 1,040-bed teaching hospital, were found to contain the plasmid-borne K. pneumoniae carbapenemase (KPC)-producing ...bla gene (blaKPC). There was evidence of person-to-person transmission for two patients. Screening of 186 clinical isolates revealed no additional blaKPC-containing isolates.
Background Clostridium difficile (CD) is the leading cause of health care–associated diarrhea and can result in asymptomatic carriage. Rates of asymptomatic CD colonization on hospital admission ...range from 1.4%-21%. The objective of this study was to evaluate host and bacterial factors associated with colonization on admission. Methods The Consortium de recherche québécois sur le Clostridium difficile study provided data for analysis, including demographic information, known risk factors, and potential confounding factors, prospectively collected for 5,232 patients from 6 hospitals in Quebec and Ontario over 15 months from 2006-2007. Stool or rectal swabs were obtained for culture on admission. Pulsed-field gel electrophoresis was performed on the isolates. The presence of antibody against CD toxins A and B was measured. Results There were 212 (4.05%) patients colonized with CD on admission, and 5,020 patients were not colonized with CD. Multivariate logistic regression analysis showed that hospitalization within the last 12 months, use of corticosteroids, prior CD infection, and presence of antibody against toxin B were associated with colonization on admission. Of patients colonized on admission, 79.4% had non-NAP1, non-NAP2 strains. Conclusion There are identifiable risk factors among asymptomatic CD carriers that could serve in their detection and provide a basis for targeted screening.
Empirical antibiotics at the onset of febrile neutropenia are one of several strategies for management of bacterial infections in patients undergoing Hematopoietic Stem Cell Transplant (HSCT) ...(empiric strategy). Our HSCT program aims to perform HSCT in an outpatient setting, where an empiric antibiotic strategy was employed. HSCT recipients began receiving intravenous antibiotics at the onset of neutropenia in the absence of fever as part of our institutional policy from 01 Jan 2009; intravenous Prophylactic strategy. A prospective study was conducted to compare two consecutive cohorts Year 2008 (Empiric strategy) vs. Year 2009 (Prophylactic strategy) of patients receiving HSCT. There were 238 HSCTs performed between 01 Jan 2008 and 31 Dec 2009 with 127 and 111 in the earlier and later cohorts respectively. Infection-related mortality pre- engraftment was similar with a prophylactic compared to an empiric strategy (3.6% vs. 7.1%; p = 0.24), but reduced among recipients of autologous HSCT (0% vs. 6.8%; p = 0.03). Microbiologically documented, blood stream infections and clinically documented infections pre-engraftment were reduced in those receiving a prophylactic compared to an empiric strategy, (11.7% vs. 28.3%; p = 0.001), (9.9% vs. 24.4%; p = 0.003) and (18.2% vs. 33.9% p = 0.007) respectively. The prophylactic use of intravenous once-daily ceftriaxone in patients receiving outpatient based HSCT is safe and may be particularly effective in patients receiving autologous HSCT. Further studies are warranted to study the impact of this Prophylactic strategy in an outpatient based HSCT program.
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