Study on drug resistance genes and molecular epidemiology of Acinetobacter baumanii in some areas of Nanjing City / 国际检验医学杂志

ABSTRACT

Objective To investigate the drug resistance genes of Acinetobacter baumanii in some areas of Nanjing City,and to explore the molecular epidemiology characteristics of different antibiotic resistant strains.Methods A total of 75 strains of Acinetobacter baumanii were isolated from three hospitals of Nanjing city from May 2015 to May 2016 and the strains were identified by microbial identification system.Drug resistances of the strains were determined by KB method.The genotypes of strains were analyzed by pulsed field gel electrophoresis,and PCR was used to amplify the resistance genes.The molecular epidemiology of Acinetobacter baumanii was studied.Results Seventy five strains of Acinetobacter baumanii all had high drug resistance to antibiotics except tigecycline and colistin.The rates of resistance to cefepime,ceftazidime,cefotaxime,ciprofloxacin,cefotaxime,tetracycline were all higher than 90％.The strains were mainly divided into 5 types,and the proportion of A type and B type accounted for 42.67％ and 37.33 ％.The positive rates of genes OXA-23,OXA-24,TEM,SHV,CTX-M,IMP-1,IMP-2 and VIM-2 were 81.33 ％,9.33％,66.67％,10.67％,42.67％,26.67％,16.00％ and 21.33％ respectively.Conclusion A type and B type of the Acinetobacter baumanii are the most popular in hospitals of Nanjing,and the strains are multiple drug resistance.The expression of main resistance genes OXA-23 and TEM strains may be the main mechanism for the higher resistance of the bacteria to antibiotics and β-amide antibiotics.