Drug resistance of acinetobacter baumannii and preliminary study on β-lactam resistance genes

OBJECTIVE To analyze the antibiotic resistance of Acinetobacter baumannii isolated from clinical patients,and to study on the carbapenemase genotype of imipenem-resistant strains.METHODS The VITEK 2 identification system was used for the identification and susceptibility test of the 85 bacterial isolates,the polymerase chain reaction(PCR) was used to detect the carbapenemase genotype of imipenem-resistant strains.RESULTS Among 85 strains of A.baumannii,the drug resistance to ampicillin was the highest(94.1%),and the drug resistant rate to imipenem was 64.7%.There were 46 bacterial isolates(83.6%) carried carbapenemase OXA-23 gene,32(58.2%) isolates carried OXA-64-like gene and 13(23.6%) isolates carried OXA-58 gene.The gene-positive strains were randomly selected and sequenced,and these isolates were found to be homologous(99.0%) with the standard sequences provided from GenBank.The remaining OXA-20,OXA-24 and OXA-48 genes were negative.CONCLUSION The resistance of A.baumannii to β-lactam antibiotics is serious,and most of the isolates carry OXA-23-type carbapenemase gene.