Detection of antibiotic resistance in vitro of klebsiella pneumoniae and Es-cherichia coli strains producing extended spectrum-beta-lactamase by agar dilution method

Objective To study comparatively the resistance of strains from isolat-ed pneumoniae and escherichia coli,extended-spectrum beta-lactamases(ESBLs)produt-ing and ESBLs non-Producing,against13kinds of antibiotics by agar dilution method.Methods Twenty nine strains of Escherichia coli.and30strains of klebsiellea pneumo-niae producing ESBLs were detemided by a double-disk synergy test and antibiotic resis-tance test against13kinds of commonly used antibiotics by agar dilution method.Re -sults A to tal of37.7%of strains were ESBLs positive.Of them klebsiella pneumoniae and escherichia coli producing ESBLs accounted for46.7%and33.35respectively.The resistance rate of non-ESBLs producing stains was below18%,MIC 50 =0.125-8,MIC 90 =0.5-64(excluding ATM,CIP,TCL were20%to40%).The resistance rate of ESBLs-producing strains against CPS was18.2%,against aminoglycosides,quinolowes were50%,MIC 50 =256,MIC 90 =256-512.But none of them was resistant to IPM and CMZ.ESBLs-producing strains had higher resistance rate against CIP,TCL,ATM,GM,(58.3～100%in Escherichia Coli.and40～60%in klebsiella pneumoniae respectively)Conclu sions To deal with the ESBLs-producing strains such antibiotics as IPM and CMZ.β-lactama /β-lactamase inhibitor combinations can be used.