Study on drug resistance genes of PERtype extendedspectrum βlactamases in Acinetobacter baumannii

Abstract:

ObjectiveTo investigate molecular epidemiological characteristics and antimicrobial resistance mechanism of PERtype extendedspectrum βlactamases (ESBLs)producing Acinetobacter baumannii(A. baumannii). Methods129 A.baumannii clinical strains isolated from a hospital between January and May 2009 were performed antimicrobial susceptibility testing by KirbyBauer disk diffusion method, PER gene was amplified by polymerase chain reaction (PCR),PCR amplified products of PER gene were sequenced, genotypes were identified by enterobacterial repetitive intergenic consensusPCR (ERICPCR).ResultsPER1 gene was detected in 78 of 129 clinical isolates, positive rate was 60.47%（78/129）. The resistance rates of PER1positive strains to imipenem, meropenem, ampicillin/sulbactam, minocycline and cefoperazone/sulbactam was 46.15%, 44.87%, 38.46%, 10.26% and 8.97% respectively,the resistance rates to the other 10 kinds of antimicrobial agents were all >60%; The resistance rates of PER1positive strains to ceftazidime, cefotaxime, cefepime, ciprofloxacin, and levofloxacin were significantly higher than PER1negative strains (all P<0.05). 78 PER1positive strains were divided into 7 types, including type A(1), B(1), C(55), D(18), E(1), F(1), and G(1), of which the main clones were type C and D.ConclusionType C and D PER1positive A.baumannii are the main epidemic strains in this hospital. PER1type ESBLproducing A.baumannii strains are multidrug resistant, minocycline and cefoperazone/sulbactam are optimal antimicrobial agents for treating A. baumannii infection in this hospital.