[Coagulase type and antimicrobial susceptibility of Staphylococcus aureus isolated from various areas in Taiwan]

A total of 129 strains of Staphylococcus aureus, isolated from clinical specimens in Taiwan between February 1992 and December 1993, were subjected to coagulase typing and susceptibility testing to 21 kinds of antimicrobial agents using Pasco MIC Gram-positive panels. In the determination of minimum inhibition concentration (MIC), there were 94 strains (72.9%) resistant to penicillin and ampicillin, 54 strains (41.9%) resistant to tetracycline and erythromycin, and 21 strains (16.3%) resistant to oxacillin (oxacillin-resistant S. aureus; ORSA), but none of them was resistant to vancomycin or nitrofurantoin. As the susceptibility of the isolates from four different geographic districts was compared, no statistical difference was found except that the resistance rate to penicillin and ampicillin was higher in southern Taiwan, and resistance rate to rifampin and gentamicin was higher in central Taiwan. The ORSA strains were all resistant to penicillin, ampicillin, tetracycline; 95.2% of the strains were resistant to gentamicin, tobramycin and erythromycin. The resistance rates to drugs tested for ORSA strains were statistically higher than those for OSSA strains except vancomycin, nitrofurantoin, trimethoprim/sulfamethoxazole and ampicillin/sulbactam. In the coagulase typing of 127 strains, Type IV, III and VII were most frequently encountered. Among the coagulase types, Type IV was mostly encountered in the North, the South and the East of Taiwan; Type III was mostly encountered in central Taiwan. Among the ORSA strains, coagulase Type III was most predominant (85%). In conclusion, analysis of an antibiogram is easy to perform and the results can provide clinicians not only with correct guides for patient treatment but also with a useful tool for epidemiological studies. However, if antibiogram and coagulase typing are carried out simultaneously, results will be more reliable in epidemiological studies, including nosocomial infection survey.