Detection on the phenotype and the genotype of the plasmid-mediated ESBLs-encoding genes of Acinetobacter baumannii with the infection at the lower respiratory tract

Objective To investigate the antimicrobial resistance and the genotype of the plasmid-mediatedβ-lactamases-encoding genes of Acinetobacter baumannii producing extended-spectrumβ-lactamases(ESBLs),which cause the infection at the lower respiratory tract.Methods35strains of Acinetobacter baumannii were isolated from hospitalized patients,antimicrobial a gents susceptibility were tested by microdilute tests and ESBLs were tested by three-dimensional tests.Genotypes of ESBLs was analyzed by PCR and verificated by DNA sequencing.Results ES BLs were positive in29of35(82.9%),and14strains produced AmpC enzyme simultaneously.On ly4sorts of antimicrobial,as Imipenem,Meropenem,Cefoperazone/Sulbactam,Polymyxin E,to all of the strains are sensitivity.The resistance rates of antimicrobial of Amoxycillin/Clavularic Acid,Ticarcillin/Clavulanic Acid,Piperacillin/Tazobactam were40.1%,40.0%,48.6%respectively.The resistant rates to other antimicrobial agents were more than50%.TEM typeβ-lactamases gene were positive in all of the35strains with TEM-1.SHV typeβ-lactamases gene were positive in15of35isolated strains,13of which were SHV-12,the other strains(HZ01and HZ29)were2sorts of novel SHV typeβ-Lactamases genes nominated SHV-48and SHV-56respectively.Conclusions There are very high rate of ESBLs-producing strains in Acinetobacter baumannii isolated from Huzhou of Zhejiang province.The multiple-drug-resistance of Acinetobacter baumannii proucing ESBLs was a serious issue and at least4kinds ofβ-lactamases genes exsisted including TEM-1,SHV-12,SHV-48and SHV-56.