병원과 지역사회에서 메티실린 내성 황색 포도상구균(methicillin-resistant Staphylococcus aureus)감염의 임상 분자역학 연구

Abstract

Background Until recently, methicillin-resistant Staphylococcus aureus (MRSA) infection has been acquired primarily in hospital settings. During the late 1990s, the incidence of community-acquired MRSA infections has been increased in this university hospital. This retrospective study evaluated the clinical features and risk factors for community-acquired MRSA infection compared with hospital-acquired MRSA infection; and molecular relatedness of MRSA strains determined by pulsed-field gel electrophoresis(PFGE).

Method MRSA isolates collected from patients during October of 1998 were classified as community-acquired("community') or hospital-acquired("hospital") cases. MRSA infections were defined as hospital-acquired if organisms were isolated > 48 hours after admission to the hospital or isolated from patients with a history of admission to a hospital within the last 3 months. A comparative analysis of risk factors for community MRSA compared with hospital MRSA was performed. mecA gene PCR and PFGE of MRSA isolated was used as a tool of strain identification and molecular typing.

Result During one month, there were 42 patients with MRSA infection or colonization. Of 42 patients with MRSA isolates, 22(52%) were hospital cases and 20(48%) were community cases. Previous exposure to antibiotics(17 vs 5, p = 0.001) and presence of underlying diseases (18 vs 8, p = 0.002) were more common in hospital cases than in community cases. MRSA were more frequently isolated in otorrhea specimens from patients with otitis media in community cases compared with hospital cases. Of the 40 MRSA isolates subjected for PFGE typing, 18 were community isolates and 22 were hospital isolates. There were 8 distinct PFGE types among the 18 community isolates and type A was the most common clonal type (7/18, 38.8%). 22 hospital isolates were of 6 distinct PFGE types, and type A was dominant clonal type (15/22, 68%). PGFE subtyping indicated that 15(83.3%) of 18 community MRSA strains were clonally related with that of 21 hospital MRSA strains.

Conclusion Our results suggest that hospital MRSA strains may have disseminated in the community setting. PFGE subtyping support the finding that MRSA is circulating beyond nosocomial settings in the regional community.