Louise Poirier

Host and Pathogen Factors for Clostridium difficile Infection and Colonization

BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.).

Clostridium difficile Infections in a Canadian Tertiary Care Hospital before and during a Regional Epidemic Associated with the BI/NAP1/027 Strain

ABSTRACT Since 2002, an epidemic of Clostridium difficile infections has occurred in southern Quebec, Canada. At Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada, the incidence of C. difficile infections increased from 11/1,000 admissions (1999 to 2002) to 27/1,000 admissions (2003 to 2005). We compared the exposures and outcomes for patients infected with strains with different ribopatterns isolated before (n = 55) and during (n = 175) the epidemic, as well as the in vitro activities of antibiotics against those isolates. During the preepidemic period, 46 isolates (84%) were of ribotype 001, 1 was of ribotype 027, and 8 were of other ribopattern types. During the epidemic period, ribotype 027 strains accounted for 140 (80%) isolates; 26 (15%) were of ribotype 001, and 7 were of other ribopattern types. Ribotype 027 strains were highly resistant to fluoroquinolones (FQs) but were susceptible to clindamycin. A pattern of prior specific antibiotic exposure that selected for antibiotic-resistant ribotype C. difficile infections was observed for FQs (ribotype 027) and clindamycin (ribotype 001). The rate of mortality was higher among older patients, those with a high Charlson comorbidity index, and those with longer previous hospitalizations. By multivariate analysis, patients infected with ribotype 027 were twice as likely to die within 30 days of diagnosis than patients infected with other ribotypes (adjusted odds ratio, 2.06; 95% confidence interval, 1.00 to 4.22). The observations from this study support the notion that continued selective antibiotic pressure resulted in the superimposition of the hypertoxigenic ribotype 027 clone on top of the prior dominant ribotype 001 clone in a setting of preexisting high endemicity, thus leading to the high rates of morbidity and mortality seen in the Quebec outbreak. Stringent antibiotic stewardship measures, combined with aggressive infection control, are required to curtail the epidemic of C. difficile infections.

In vitro susceptibility of Clostridium difficile clinical isolates from a multi-institutional outbreak in Southern Québec, Canada.

ABSTRACT Clostridium difficile isolates from a 2004 outbreak in Québec, Canada, were all found to be susceptible to metronidazole, vancomycin, rifampin, and meropenem but resistant to bacitracin, cefotaxime, ciprofloxacin, and levofloxacin, and most (>80%) were resistant to ceftriaxone, clarithromycin, gatifloxacin, and moxifloxacin. The predominant NAP1 isolates were susceptible to clindamycin, while the NAP2 isolates were resistant.

Predictors of asymptomatic Clostridium difficile colonization on hospital admission

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.

Comparing and Transforming: An Application of Piaget’s Morphisms Theory to the Development of Class Inclusion and Arithmetic Problem Solving

In his final works, Piaget suggested formalizing the developmental processes operating in different fields in terms of the mathematical theory of morphisms and categories. This new approach is used to

Teaching mathematics and the Inuit community

In the spring of 2000, the Inuit community and the Kativik School Board were pondering the difficulties encountered by students in mathematics and the measures that could be taken to help these students. One significant fact that it seemed might help explain these difficulties was that Inuit students learn Inuit mathematics (for example, a base-20 numeral system) in their own language in the first three years of their schooling and then go on to study in either French or English. A collaboration between researchers, teachers from the Inuit community, and curriculum developers was established. In this article, we present facets of the environment, language, and culture of the Inuit that influenced the development of the Inuit numeration system, their ways of measuring (length, distance, time, etc.), and their great aptitude in spatial representations. We then discuss the current collaborative project that aims at the development of teaching situations adapted to Inuit classrooms.RésuméAu printemps 2000, la communauté Inuit et la commission scolaire Kativik s’interrogeaient sur les difficultés qu’éprouvent les élèves en mathématiques et sur les actions à prendre pour aider les élèves. Un facteur important pour expliquer de telles difficultés tient au fait que les élèves inuit apprennent durant leurs trois premières années d’école, les mathématiques traditionnelles inuit dans leur langue (par exemple, ils ont recours à un système de nombres en base 20) puis poursuivent leur apprentissage en français ou en anglais. Un projet de recherche collaborative a été mis sur pied impliquant des enseignants inuit, des responsables du développement de programme et des chercheurs. Dans cet article, nous présentons quelques éléments de leur environnement, de leur langue et de leur culture qui ont amené les Inuit à développer leurs mathématiques. Des exemples en arithmétique, en mesure et en relations spatiales sont présentés. Nous terminons par une discussion autour du projet de recherche collaborative qui a pour but le développement de situations d’enseignement adaptées au contexte Inuit.

Hepatitis E: A newcomer to the hepatitis alphabet - Case report and review of the literature

The first Canadian case of hepatitis E is described in a patient who travelled to Asia for a six-month period and spent most of his time in India. Hepatitis E shares some similarities with hepatitis A, notably the mode of transmission and the absence of chronic course. However, a few important differences have been noted, including a higher mortality rate and a high fatality rate in pregnant women. Hepatitis E is very common in developing countries and should be suspected more often in individuals with gastrointestinal complaints returning from endemic areas.

Activity of Trovafloxacin Against Micro-Organisms Isolated from Diabetic Patients with Lower Extremity Infections

Diabetic foot infections represent a major complication for patients affected by diabetes mellitus. In Ontario, Canada, 45% of all amputations of a lower extremity occur in persons with diabetes.[1] This complication represents a considerable physical, psychological and financial cost. Diabetic foot infections generally involve a mixed bacterial flora, which includes aerobic Gram-positive and Gram-negative bacteria and anaerobic micro-organisms. New quinolones such as trovafloxacin, which has a broad spectrum of activity, may become very useful for treating foot infections in patients with diabetes. Themain objectives of this studywere to determine the in vitro activity of new quinolones against microorganisms isolated from patients with diabetic foot infections, and to compare the activity of new quinolones such as trovafloxacin with antibacterials commonly used in the treatment of such infections.