Methicillin-resistant Staphylococcus aureus colonization among health care workers in a downtown emergency department in Toronto, Ontario.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) acquired in the community, otherwise known as community-acquired MRSA, has emerged rapidly in recent years. Colonization with MRSA has been associated with an increased risk of symptomatic and serious infections and, in some settings, health care workers (HCWs) exhibit a higher prevalence of MRSA colonization. OBJECTIVE: To determine MRSA colonization in emergency department (ED) HCWs in the setting of a moderate prevalence of MRSA in skin and soft tissue infections. METHODS: The present study was conducted at a downtown ED in Toronto, Ontario. ED HCWs completed a brief questionnaire and swabs were taken from one anterior nare, one axilla and any open wounds (if present). Swabs were processed using standard laboratory techniques. RESULTS: None of the 89 staff (registered nurses [n=55], physicians [n=15], other [n=19]) were MRSA positive and 25 (28.1%) were colonized with methicillin-susceptible S aureus. CONCLUSIONS: Contrary to common belief among HCWs and previous studies documenting MRSA colonization of HCWs, MRSA colonization of this particular Canadian ED HCW cohort was very low and similar to that of the local population.

HISTORIQUE: Le Staphylococcus aureus résistant à la méthicilline (SARM) d'origine non nosocomiale, ou SARM d'origine communautaire, a émergé rapidement ces dernières années. La colonisation par le SARM s'associe à une augmentation du risque d'infections graves et symptomatiques. Dans certains milieux, les travailleurs de la santé (TdS) présentent une prévalence plus élevée de colonisation par le SARM. OBJECTIF: Déterminer la colonisation par le SARM desTdS d'un département d'urgence (DU) où l'on observe une prévalence modérée de SARM en cas d'infections de la peau et des tissus mous. MÉTHODOLOGIE: Les chercheurs ont mené la présente étude dans un DU du centre-ville de Toronto, en Ontario. Les TdS du DU ont rempli un bref questionnaire et effectué un prélèvement dans une narine, sous l'aisselle et dans leurs plaies ouvertes (le cas échéant). Les prélèvements ont été traités au moyen de techniques de laboratoire standard. RÉSULTATS: Aucun des 89 employés (infirmières diplômées [n=55], médecins [n=15], autres [n=19]) n'était positif au SARM, mais 25 (28,1 %) étaient colonisés par le S aureus susceptible à la méthicilline. CONCLUSIONS: Contrairement aux idées reçues chez les TdS et aux études antérieures étayant la colonisation des TdS par le SARM, la colonisation par le SARM de cette cohorte de TdS d'un DU canadien était très faible et similaire à celle de la population locale.

Colonization and subsequent skin and soft tissue infection due to methicillin-resistant Staphylococcus aureus in a cohort of otherwise healthy adults infected with HIV type 1.

Methicillin-resistant Staphylococcus aureus (MRSA) carriage and subsequent infection were prospectively compared among a well-defined group of 107 individuals infected with human immunodeficiency virus type 1 (HIV-1) who had no evidence of immune suppression and 52 epidemiologically matched, uninfected individuals. The carriage strains and infecting strains were genetically characterized. The cumulative prevalence of MRSA carriage was significantly higher among HIV-infected individuals (16.8%) than among individuals without HIV infection (5.8%) (P = .04; odds ratio, 3.3 [95% confidence interval, 1.3-14.7]). Fifteen of 21 MRSA isolates recovered from colonized individuals were identified as strain USA300. Of the 10 MRSA skin and soft tissue infections observed in this study, all occurred in HIV-infected individuals who were colonized with the same strain that caused the infection. Previous antibiotic use was the only statistically significant risk factor for MRSA carriage. These data highlight the fact that MRSA colonization and infection are important clinical issues among asymptomatic HIV-1-infected individuals.

Verification of the IDI-MRSA assay for detecting methicillin-resistant Staphylococcus aureus in diverse specimen types in a core clinical laboratory setting.

The IDI-MRSA assay has a sensitivity of 96% and a specificity of 96% when used to screen patients at extranasal sites. This verification study used previously unverified swabs and was undertaken in a core medical laboratory using nonmicrobiology technologists trained in sample processing, molecular laboratory work flow, and PCR practice.