Screening of ?-Lactamase in Multi-resistant Gram-negative Bacilli and Analysis of Characteristics of Susceptibility of Phenotype and Genotype / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To investigate the phenotypical and genotypical characteristics of the ?-lactamase in the 302 strains of Gram-negative bacilli,and assess the characteristics of the drug resistance.METHODS The phenotypes of ?-lactamase were detected in the Gram-negative bacilli by disc diffusion screen test,which were further ascertained by disc diffusion confirmatory test,a cefoxitin three dimensional test,and metallo ?-lactamases double-disc synergy test.The ?-lactamases were detected by multiple PCR amplification,then DNA product was sequenced.Antibiotics susceptibility was detected by K-B method.RESULTS Among the clinical Gram-negative isolates,a total of 26.49%(80/302)strains′ ?-lactamases phenotypes were positive,ESBLs,ESBLs combined with AmpC enzyme,ESBLs combined with AmpC enzyme and MBL,and AmpC enzyme producing strains were found in 16.56%,6.62%,1.66% and 0.66%,respectively.A total of 24.83% strains′?-lactamases phenotypes were positive,strains produced ESBLs,ESBLs combined with AmpC enzyme,ESBLs combined with AmpC enzyme and MBL,and AmpC enzyme producing strains were found in 17.55%,6.95%,0.33%,and 0.33%,respectively.Drug-sensitivity test showed multi-resistant Gram-negative isolates were more sensitive to amikacin(18.75%),and heavier resistant to ampicillin(97.50%).CONCLUSIONS ?-Lactamase producing Gram-negative bacilli are resistant to multi-antibiotics.