[Induction of PBP2' by antibiotics and disinfectants in MRSE].
OBJECTIVE
Methicilllin-resitant Staphylococcus aureus (MRSA) is still the most important bacterium for hospital infection control, and is known to exhibit beta-lactam resistance. Moreover, the increase in PBP2'-producing methicillin-resistant coagulase-negaive Staphylococcus (MR-CNS), especially methicillin-resistant S. epidermidis (MRSE) has been problematic. In this study, we investigated the induction of PBP2' by MPIPC, other antibiotics and disinfectants in MRSE.


METHODS
The bacterial strains used were MRSE isolated in our clinical laboratory. MRSA-LA 'Seiken' was used for the detection of PBP2'. To investigate induction of PBP2' by MPIPC in MRSE, MRSE was cultured on the medium containing MPIPC at 11 different concentrations from 0.0001 to 6 microg/ml, and PBP2' induction was investigated. Strains in which no induction was noted at a low MPIPC concentration were cultured with other antibiotic discs and discs impregnated with various disinfectants, and PBP2' was detected in colonies that grew around the disc and PBP2' induction was investigated.


RESULTS
In the culture on MPIPC-supplemented medium, PBP2' was detected in all strains at 0.01-6 microg/ml. At 0.001 and 0.0001 microg/ml, 8/10 and 4/10 were positive, respectively. Addition of another beta-lactam, particularly cephem antibiotics, induced PBP2' in some strains that were negative at 0.0001 microg/ml. In cultures with disinfectants, inhibition zones were noted, but no PBP2' was induced.


CONCLUSIONS
PBP2' was induced by a low beta-lactam and was not by disinfectants in MRSE.
Hen
Karen
K
Department of Laboratory Medicine, Fukushima Medical University, School of Medicine, Fukushima 960-1247, Japan.
Imafuku
Yuji
Y
Yoshida
Hiroshi
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology; D003470:Culture Media; D004202:Disinfectants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology*; D046915:Penicillin-Binding Proteins / Q000096:biosynthesis*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D003470:Culture Media; D004202:Disinfectants; D046915:Penicillin-Binding Proteins; D047090:beta-Lactams; D010068:Oxacillin