Table 2

Susceptibility of Orange County nursing home MRSA isolates (n = 829) to 13 antimicrobial agents

Antimicrobial agentMIC data (μg/ml)% resistant
RangeMIC50MIC90
Chlorhexidine0.5–424NAa
Clindamycin≤0.12 to >16>16>1655
Erythromycin≤0.25 to >32>32>3290
Tetracycline≤0.5 to >64≤0.5≤0.54
Trimethoprim-sulfamethoxazole≤0.25 to >32≤0.25≤0.252
Gentamicin≤0.5 to >64≤0.56412
Levofloxacin≤0.25 to >3232>3298
Vancomycin0.5–2110
Daptomycin≤0.5–4≤0.5≤0.5NA
Quinupristin-dalfopristin≤0.5–4≤0.5≤0.5<1
Linezolid≤1–822<1
Rifampin≤0.5 to >4≤0.5≤0.51
Mupirocinb
    Low-level resistance isolates3
    High-level resistance isolates9
  • a NA, not available, because the Clinical and Laboratory Standards Institute has not yet established breakpoints for resistance to this agent.

  • b Disk diffusion testing was performed, and so no MICs are reported here.