Susceptibility Pattern of Staphylococcus Aureus(SA) : Methicillin Resistant(MRSA) vs. Sensitive Strains(MSSA)

다국어 초록 (Multilingual Abstract)

The importance of MIRSA in infections due to SA continues to increase while alternative agents are limited. To study the changing patterns of in vitro susceptibility of SA, a total of 200 SA strains (100 MRSA / 100 MSSA) over two time periods (1987 / 1989) were tested against 16∼25 antibiotics including 8 quinolones.
MICs were measured by microdilution method in BHI broth at 35^0 with 10^5 cfu / ml inoculum size. MRSAs revealed a high drug resistance pattern with resistance rate of 90% for clindamycin, gentamicin, and rifampin(94%) over the time periods. Ciprofloxacin showed the highest increase in resistance with 46% incidence in 1989 vs 0% in 1987. MSSAs remained susceptible to vancomycin(100%), minocyclin(98%), rifampin(98%), clindamycin(90%), gentamicin(90%), and ciprofloxacin(90%).
It is concluded that methicillin susceptibility is a useful marker for SAs in predicting drug sensitivity. Minocyclin and rifampin may be useful alternative agents where vancomycin is contraindicated.