[Susceptibility and beta-lactamase-producing strains of methicillin-resistant Staphylococcus aureus].
Thirty-three strains of methicillin-resistant Staphylococcus aureus (MRSA, MIC for methicillin greater than or equal to 16.0 micrograms/ml) isolated from sputum were examined for their susceptibilities against 8 antimicrobial agents. Ampicillin (ABPC), methicillin (DMPPC), cefazolin (CEZ), minocycline (MINO), erythromycin (EM), tobramycin (TOB), refampicin (RFP), and ofloxacin (OFLX) were used as the antimicrobial agents. The production of beta-lactamase was also determined. The results are as follows: 1) The highest susceptibility was given by RFP, and followed by MINO, and OFLX. All strains were resistant against EM and TOB. 2) The percentage of beta-lactamase-positive strains was 75.8%, which was distributed nearly identical among each MIC to DMPPC (72.0-77.8%). 3) Since the beta-lactamase-positive strains were found among the sensitive strains to ABPC, it was suggested that the use of beta-lactam antimicrobial agents might bring into the higher MIC value to ABPC. 4) Since there were beta-lactamase-negative strains among the resistant strains to ABPC, it was indicated that penicillin binding protein-2' might be produced by giving beta-lactam antimicrobial agents.
Akimoto
Y
Y
Kaneko
K
K
Fujii
A
A
D000668:Ampicillin Resistance; D002437:Cefazolin / Q000494:pharmacology; D004917:Erythromycin / Q000494:pharmacology; D016106:Methicillin Resistance; D008911:Minocycline / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000201:enzymology*; D014031:Tobramycin / Q000494:pharmacology; D001618:beta-Lactamases / Q000096:biosynthesis*
D004917:Erythromycin; D001618:beta-Lactamases; D008911:Minocycline; D002437:Cefazolin; D012293:Rifampin; D014031:Tobramycin