Abstract
In vitro combination effect of teicoplanin and β-lactams was investigated against 109 MRSA strains isolated from a variety of clinical specimens at the Social Health Insuarance Medical Center during the period from January 1994 thrugh February 2000. TEIC+panipenem (PAPM) was revealed by microbroth dilution method-based checkerboard method, to exhibit synergistic effect of min. FIC index ≤0.5 against all the 109 strains. The combination of TEIC and flomoxef (FMOX) was shown to have synergistic effect on 108 strains (99.1%). The combination of TEIC and cefepime (CFPM) was shown to have synergistic effect on 96 strains (88.1%). The combination of TEIC and cefmetazole (CMZ) was shown to have synergistic effect on all the 109 strains (100%). The mean value of min. FIC indices obtained from each of the combinations was 0.1259 as to TEIC+PAPM, 0.2019 as to TEIC+FMOX, 0.3257 as to TEIC+CFPM and 0.1995 as to TEIC+CMZ, in other words, the combi-nation of TEIC+PAPM showed the lowest value of all the combinations. While MIC80 was 2.0μg/ml when TEIC was used alone, it was ≤0.06μg/ml when used together with PAPM, and 0.13μg/ml when used together with FMOX, respectively. While MIC80 was 3.2μg/ml when PAPM was used alone, it was 0.5μg/ml when used together with TEIC. Meanwhile, the value for FMOX was changed from≤μg/ml to 4.0 μg/ml. When TEIC was used in combination with CFPM, MIC80 was found to be 0.5μg/ml. Similar to the case of the concurrent use with FMOX, the value obtained by combination with CMZ was 0.13μg/ml. While MIC80 was 128μg/ml when CFPM was used alone, it was 8.0μg/ml when used together with TEIC, whereas the value for CMZ was decreased from 64μg/ml to 2.0 μg/ml. In conclusion, TEIC's antibacterial activity was shown to be accentuated by any of the combinations.
