Susceptibility of methicillin-resistant Staphylococcus aureus to minocycline and other antimicrobials.

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) is on the rise, especially in nosocomial and intravenous-drug-abuse-related infections, with a concomitant increase in morbidity, mortality and health care costs. At present the drug of choice, vancomycin, which must be administered intravenously, is expensive and can cause serious side effects in vancomycin-intolerant patients. Recently, minocycline has received much attention as an antibiotic to combat the increasing frequency of MRSA-related infections. We tested 102 recent clinical isolates of MRSA from tertiary-care patients and found none to be resistant to minocycline, with minimum inhibitory concentrations of < 1-2 micrograms/ml. The only other drug that inhibited all the strains was vancomycin, followed by ciprofloxacin (87%), clindamycin (55%) and chloramphenicol (52%). Gentamicin, beta-lactams, tetracycline and trimethoprim-sulfamethoxazole had little or no activity against our isolates of MRSA.