Methicillin-resistant Staphylococcus aureus in an adult military beneficiary population lacking risk factors:: Susceptibility to orally available agents

To determine the unique susceptibility of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) as a function of the presence or absence of risk factors in a military beneficiary population, we reviewed all MRSA cases between 1994 and 1997 in a military medical center. Of 67 cases, 24 were community acquired, 9 of whom lacked risk factors for MRSA infection, and 43 cases were nosocomial. Among isolates from patients without risk factors, seven (77.8%) were susceptible to ciprofloxacin, eight (88.9%) to trimethoprim/sulfamethoxazole, eight (88.9%) to erythromycin, eight (88.9%) to tetracycline, and nine (100.0%) to clindamycin. These rates were markedly higher than those seen in isolates obtained from community-acquired cases with risk factors as well as from nosocomial cases (p < 0.01). Three clonal types of MRSA from patients without risk factors were identified and susceptibilities were similar for each of the three types. These results indicate that therapy with active oral agents might be reasonable for some less severe MRSA infections in our active duty military patients without risk factors, and additional studies are merited.