Study on genotypes of β-Lactamases producing Acinetobacter baumannii.

Objective To explore the antimicrobial resistance of Acinetobacter baumannii and the genotype of multidrug-resistant β-Lactamase producing Acinetobacter baumannii isolated from clinical specimens in order to provide the laboratory information for effective control and treatment of the infectious diseases.Method Kirby-Bauer(K-B) tests were performed to detect the susceptibility of 312 strains of Acinetobacter baumannii to 13 kinds of antimicrobial agents.The genotypes of β-Lactamase producing gene in multidrug-resistant Acometobacter baumannii were detected by multiple PCR amplification and then the DNA products were sequenced.Result The resistance rates of the 312 Acinetobacter baumannii isolates to Imipenam,Cefoperazone/sulbactam and Ticarcillin/clavulanic were 1.0%,30.8% and 31.4%,respectively.The resistance rates to other antimicrobial agents were between 38.5%～80.1%.The positive rates of AmpC,SHV-12,PER-1,CTX-M-9 and TEM-1 among β-Lactamase genes in 120 multidrug-resistant strains were 66.7%(80/120),14.2%(17/120),16.7%(20/120),8.2%(10/120) and 9.2% (11/120),respectively.VER-1,CTX-M-1,CTX-M-2 and OXA genes were not found.There were two different genes in 16 strains,and three different genes in 14 strains.Conclusion Strains that produce AmpC were predominant among Acinetobacter baumannii isolated from clinical specimens and were also multiresistant.