Induction of ?-Lactams on L1,L2 ?-Lactamases from Stenotrophomonas maltophilia / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To compare commonly used antibiotics including cefotaxime,ceftazidime imipenem and meropenem inductivity to L1,L2 ?-lactamases from Stenotrophomonas maltophilia.METHODS RT-PCR method was used to determine the expression of L1,L2 ?-lactamases under the condition of different concentrations(1/4,1,4?MIC)of antimicrobial agents.Electrophoresis strip of L1,L2 ?-lactamases was quantified by software Image J.Minimal inhibitory concentrations(MICs)were detected by agar dilution method when different concentrations of antibiotics were as inductors.RESULTS Different concentrations of four antibiotics being used as inductors,electrophoresis strips of L1,L2 amplicons were not found in strains of blank control and those whose media had imipenem,meropenem or cefotaxime(4?MIC).The weaker electrophoresis strips were found in the isolates whose media had ceftazidime(1/4,1,4?MIC)or cefotaxime(1/4?MIC),but the strongest electrophoresis strips,the most quantities of expression and higher MICs were shown in the isolates whose media had cefotaxime(1?MIC)(P