Molecular epidemiology of MRSA in the Brazilian primary health care system.

OBJECTIVE: To evaluate the molecular epidemiology and to georeference Staphylococcus aureus isolated from wounds and nares of patients seen at Basic Health Units (BHUs) of a Brazilian city.

METHODS: Observational, cross-sectional study conducted from 2010 to 2013. A total of 119 S. aureus strains isolated from the wounds and nares of 88 patients were studied. The isolates were characterized by identifying virulence genes encoding enterotoxins A-E, hemolysins α, β and δ, exfoliatins A, B and D, biofilm production, Panton-Valentine leukocidin and toxic shock syndrome toxin 1, and by pulsed-field gel electrophoresis(PFGE), multilocus sequence and spa typing.

RESULTS: Eighteen MRSA (6 SCCmec type II and 12 SCCmec type IV) and 101 (85%) MSSA were identified. PFGE typing resulted in the formation of eight clusters, with STs 1, 5, 8, 30, 188, 1176 and 1635 and spa type t002 a being the predominant types among MSSA. The 18 MRSA belonged to STs 5, 8 and 1176 and spa types t002 and t062.

CONCLUSION: The results demonstrate widespread dissemination of MSSA and MRSA clones carrying hemolysin, biofilm and toxin genes. Kernel density estimation revealed the highest density of S. aureus in the 4, 5 and 8 BHUs. This article is protected by copyright. All rights reserved.