Les inhibiteurs de pompes à protons comme facteur de risque pour les diarrhées à Clostridium difficile chez des patients de soins intensifs

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Characteristics of Clostridium difficile infection in patients with discordant diagnostic test results

Background: Clinical features of Clostridium difficile infection (CDI) cases diagnosed by detection of polymerase chain reaction (PCR), with negative toxin enzyme immunoassay results (EIA) have not been fully elucidated. The purpose of this study was to determine the magnitude of CDI patients who had negative EIA toxin determinations but positive PCR tests, and their differences in clinical presentation. Methods: We performed a retrospective study comparing the clinical features of CDI cases detected by EIA (toxins A + B) with cases detected by PCR (toxin negative, PCR positive) over a 16-month period. Only patients with an initial Clostridium difficile infection episode that fulfilled a standardized definition were included. Results: During the study period, 107 episodes of CDI were detected. Seventy-four patients (69%) had positive glutamate dehydrogenase (GDH) antigen and EIA determinations (EIA positive patients). Thirty-three patients (31%) had GDH positive, negative toxin EIA and positive PCR determination (PCR positive patients). PCR positive patients were younger, 57 (27) years (mean [SD]), than EIA positive patients, 71 (16) years, (p < 0.001). Fewer PCR positive patients were receiving proton pump inhibitors (21 patients, 64%) than EIA positive patients (61 patients, 82%, p = 0.034). The clinical presentation was similar in both groups. In the multivariate analysis, lower age was identified as the only independent variable associated with PCR positive patients. Conclusions: One third of Clostridium difficile infection patients present negative toxin EIA and PCR positive tests. Performing PCR determination after the negative EIA test is more relevant in younger patients.

Recognition of greater diversity of Bacillus species and related bacteria in human faeces

In a study looking at the culturable, aerobic Actinobacteria associated with the human gastrointestinal tract, the vast majority of isolates obtained from dried human faeces belonged to the genus Bacillus and related bacteria. A total of 124 isolates were recovered from the faeces of 10 healthy adult donors. 16S rRNA gene sequence analyses showed the majority belonged to the families Bacillaceae (n = 81) and Paenibacillaceae (n = 3), with Bacillus species isolated from all donors. Isolates tentatively identified as Bacillus clausii (n = 32) and B. licheniformis (n = 28) were recovered most frequently, with the genera Lysinibacillus, Ureibacillus, Oceanobacillus, Ornithinibacillus and Virgibacillus represented in some donors. Phenotypic data confirmed the identities of isolates belonging to well-characterized species. Representatives of the phylum Actinobacteria were recovered in much lower numbers (n = 11). Many of the bacilli exhibited antimicrobial activity against one or more strains of Clostridium difficile, C. perfringens, Listeria monocytogenes and Staphylococcus aureus, with some (n = 12) found to have no detectable cytopathic effect on HEp-2 cells. This study has revealed greater diversity within gut-associated aerobic spore-formers than previous studies, and suggests that bacilli with potential as probiotics could be isolated from the human gut.

C. difficile surveillance quarterly report: October-December 2010

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensiveoverview of all C. diff infections, rates, trends, age-specific informationand statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: January-March 2011

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: July - September 2011

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: October - December 2011

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: January - March 2012

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: October - December 2012

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile surveillance quarterly report: October-December 2010

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficle surveillance quarterly report: April - June 2011

This quarterly report provides epidemiological data on C. difficile in Northern Ireland, and includes key points, a comprehensive�overview of all C. diff infections, rates, trends, age-specific information�and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.

C. difficile and S.aureus bacteraemia surveillance quarterly reports

Quarterly reports provide epidemiological data on�C. difficile and S. aureus�in Northern Ireland. The report highlights key points, rates, trends and statistical process control charts. The report also provides information on surveillance methods and data for each hospital and Health and Social Care Trust in Northern Ireland.Click here to see the latest reports

C. difficle surveillance quarterly report: July-September 2015

This quarterly report provides epidemiological data on�C. difficile�in Northern Ireland, and includes key points, a comprehensive�overview of all�C. diff�infections, rates, trends, age-specific information�and statistical process control charts.

Phenotypic and genotypic characterisation of Clostrum Difficile

Clostridium difficile is at present one of the most common nosocomial infections in the developed world. Hypervirulent strains (PCR ribotype 027) of C. difficile which produce enhanced levels of toxins have also been associated with other characteristics such as a greater rate of sporulation and resistance to fluoroquinolones. Infection due to C. difficile PCR ribotype 027 has also been associated with greater rates of morbidity and mortality. The aim of this thesis was to investigate both the phenotypic and genotypic characteristics of two populations of toxigenic clinical isolates of C. difficile which were recovered from two separate hospital trusts within the UK. Phenotypic characterisation of the isolates was undertaken using analytical profile indexes (APIs), minimum inhibitory concentrations(MICs) and S-layer protein typing. In addition to this, isolates were also investigated for the production of a range of extracellular enzymes as potential virulence factors. Genotypic characterisation was performed using a random amplification of polymorphic DNA(RAPD) PCR protocol which was fully optimised in this study, and the gold standard method, PCR ribotyping. The discriminatory power of both methods was compared and the similarity between the different isolates also analysed. Associations between the phenotypic and genotypic characteristics and the recovery location of the isolate were then investigated. Extracellular enzyme production and API testing revealed little variation between the isolates; with S-layer typing demonstrating low discrimination. Minimum inhibitory concentrations did not identify any resistance towards either vancomycin or metronidazole; there were however significant differences in the distribution of antibiogram profiles of isolates recovered from the two different trusts. The RAPD PCR protocol was successfully optimised and alongside PCR ribotyping, effectively typed all of the clinical isolates and also identified differences in the number of types defined between the two locations. Both PCR ribotyping and RAPD demonstrated similar discriminatory power; however, the two genotyping methods did not generate amplicons that mapped directly onto each other and therefore clearly characterised isolates based on different genomic markers. The RAPD protocol also identified different subtypes within PCR ribotypes, therefore demonstrating that all isolates defined as a particular PCR ribotype were not the same strain. No associations could be demonstrated between the phenotypic and genotypic characteristics observed; however, the location from which an isolate was recovered did appear to influence antibiotic resistance and genotypic characteristics. The phenotypic and genotypic characteristics observed amongst the C. difficile isolates in this study, may provide a basis for the identification of further targets which may be potentially incorporated into future methods for the characterisation of C. difficile isolates.