Gentamicin-susceptible or gentamicin-resistant methicillin-resistant Staphylococcus aureus: a case-case study.

Gentamicin-susceptible methicillin-resistant Staphylococcus aureus (GS-MRSA) strains are replacing gentamicin-resistant MRSA (GR-MRSA) strains. We showed that exposure to other patients harboring GS-MRSA was the major risk factor for GS-MRSA acquisition, and that antimicrobial exposure, especially to beta-lactams, was strongly associated with acquisition of GR-MRSA but not GS-MRSA. Gentamicin use was significantly associated with GR-MRSA acquisition in univariate analysis only.