Carriage of drug resistance genes and homology of carbapenem-resistant Acinetobacter baumannii isolated from respiratory intensive care unit / 中国感染控制杂志

ABSTRACT

Objective To investigate drug resistance genes and epidemic characteristics of β-lactamase carried by carbapenem-resistant Acinetobacter baumannii (CRAB) in the respiratory intensive care unit(RICU) in a hospital.Methods Clinically isolated CRAB from RICU patients in October-December 2015 were collected.Five drug resistance genes (KPC-2,IMP,VIM,NDM-1,OXA-23) were specifically amplified by polymerase chain reaction (PCR),amplified products were performed agarose gel electrophoresis and sequencing analysis,the homology was analyzed with pulsed-field gel electrophoresis (PFGE).Results A total of 22 CRAB strains were isolated in October-December 2015,19 (86.36％) of which were isolated from sputum.The resistance rate of 22 CRAB strains to compound sulfamethoxazole was 59.09 ％,resistance rate to minocycline was 9.09 ％,all were sensitive to polymyxin B,resistance rates to other antimicrobial agents were more than 80％.Three kinds of resistance genes KPC-2,IMP and NDM-1 were not found by PCR amplification,positive rates of VIM and OXA-23 were both 100％.PFGE homology analysis revealed that 22 strains were divided into 13 different types,each type contained 1-5 strains,9 types(69.23％) contained only 1 strain respectively,the other 4 types (30.77％) contained 2-5 strains.A5,A7,and A8;A9,A11,A14,A19 and A22;A4,A10 and A12;A16 and A18 were of the same type respectively.Conclusion The main types of β-lactamase-resistant genes of CRAB in RICU are VIM and OXA-23.Homology analysis shows a small parts are of the same clone strains,which reveals epidemic of a small scale.