Epidemiological study on infection of methicillinresistant Staphylococcus aureus

Abstract:

ObjectiveTo investigate the infection of methicillinresistant Staphylococcus aureus (MRSA) in patients in a hospital and environmental contamination of MRSA,and study  the possible sources and transmission routes with homology analysis of MRSA isolates collected from patients and environment. MethodsStaphylococcus aureus  were identified by Vitek2 system,MRSA were identified by cefoxitin  disk diffusion method and mecA PCR, homology of MRSA isolates was analysed with randomly amplified polymorphic DNA (RAPD) analysis.ResultsAmong all  isolates of Staphylococcus aureus, the isolation rate of MRSA from clinical and environmental samples was 58.54% (24/41)and 38.10%(16/24) respectively. The numbers of amplified DNA fragments by RAPD were 4～6, typing rate was 100%. Based on clustering analysis, 24 clinical strains were divided into 4 types,and the main type was type Ⅰ(14 strains); 16 environmental strains were divided into 3 types,and the main type was also type Ⅰ(13 strains).4 patients in burn unit and 4 patients in neurosurgical department and environment isolated homologous strains.ConclusionThe isolated rate of MRSA in patients and environment in this hospital was high,the dominant epidemic strain of MRSA was type Ⅰ and clone spread might exist. Extrinsic route  was the main source for nosocomial infection caused by MRSA.