Genotype analysis of β-lactamases in Acinetobacter baumannii isolated from Guangzhou

Objective To analyze the genotypes of beta-lactamases in Acinetobacter baumanii isolated from Guangzhou area.Methods Kirby-Bauer test was performed to determine the susceptibility of 211 strains of A.baumanii to 12 antimicrobial agents.PCR and DNA sequencing were used to analyze the genes encoding β-Lactamases in 85 strains of resistant A.baumanii.Results The resistance rate of A.baumanii to meropenem,imipenem,cefoperazone-sulbactam and ticarcillin-clavulanic acid was 0,0.9%,31.4% and 31.1% respectively.The resistance rate to other antimicrobial agents ranged from 39.3% to 80.1%.Of the 85 drug-resistant strains,ampC gene was identified in 57(67.1%) strains,SHV-12 gene in 12(14.1%),PER-1 gene in 14(16.5%),CTX-M-14 gene in 7(8.2%),and TEM-1 gene in 8(9.4%) strains.Eleven strains carried two genes.Ten strains harbored 3 genes. Conclusions The antibiotic resistance of A.baumannii has close relation to concomitant presence of ampC,SHV-12,PER,CTX-M-14 and TEM-1 genes.