BackgroundTo implement effective precautions to avoid methicillin‐resistant Staphylococcus aureus (MRSA) nosocomial infections, it is important to clarify when, how, and from whom MRSA was transmitted to the patients. However, MRSA strains obtained from outpatient population were not analyzed, and the transmission routes of MRSA in the community are not completely understood. The purpose of this study was to clarify whether MRSA is spreading in community settings or whether MRSA transmission still occurs only in healthcare institutions.MethodsSurveillance cultures of 1274 residents living in a community were performed in two different areas, Kochi and Osaka prefectures of Japan. All isolated MRSA strains were evaluated using multilocus sequence typing (MLST) to clarify the transmission routes of MRSA. The results were compared with those of inpatients. Moreover, written questionnaires and medical records were analyzed.ResultsAnalysis of surveillance cultures from residents living in the community in Japan revealed an MRSA colonization rate of 0.94%. The proportion of MRSA to S. aureus colonization was 2.6% in the 310 residents, which was significantly lower than in the 393 hospitalized patients (63.1%; P < .0001). MRSA strains in residents are different from the endemic strains in the hospitalized patients. Previous hospital admission is a risk factor for MRSA infection of the endemic strain in hospital.ConclusionsMethicillin‐resistant Staphylococcus aureus colonization in community setting is rare in Japan. MLST results suggest that some MRSA strains are moving to the community through previous hospital admissions; however, MRSA is not spreading in community settings.

Background Asymptomatic carriers of methicillin‐resistant Staphylococcus aureus (MRSA) are important sources of nosocomial transmission. MRSA may be transmitted from hospitalized patients to healthcare professionals and vice versa. Methods The prevalence of MRSA colonization among forty‐five healthcare professionals in a Japanese hospital was determined by performing surveillance cultures to identify unrecognized carriers of MRSA. All MRSA isolates were evaluated using multilocus sequence typing (MLST) to identify the transmission routes. Results The proportion of MRSA colonization was significantly higher in healthcare professionals (11.1%) than in community residents (0.72%; P < 0.0001) or admission case (2.5%; P = 0.018). MLST analysis revealed that both the ST8 and ST764 strains were identified in residents, patients, and healthcare professionals. MRSA colonization was more frequently observed among physicians (4/13; 31%) than nurses (1/32; 3%) ( P = 0.020). Conclusion Multilocus sequence typing results suggest that ST8 and ST764 are involved in the occurrence of nosocomial MRSA infections. These findings emphasize the necessity for the effective education of physicians to prevent MRSA transmissions.

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