Dissemination of class D carbapenemase resistance genes and plasmid profiles of Acinetobacter baumannii isolated from Chiangrai Prachanukroh hospital, Thailand

Abstract

Acinetobacter baumannii is a gram negative bacteria causing nosocomial infection, especially in intensive care unit (ICU). In Thailand, the prevalence of carbapenem resistance A. baumannii (CR-AB) has been increasing in the past decades. The aims of this study were to determine the antibiotic susceptibility patterns, the plasmid profiles of extensively drug resistant A. baumannii (XDR-AB) and to detect the class D carbapenemase resistance genes in A. bauamannii isolated from Chiangrai Prachanukroh hospital, Thailand. The specimens were collected from July to October 2014. All A. baumannii isolates were determined antibiotic susceptibility pattern by the disk diffusion method. Our results showed the prevalence of carbapenem resistance A. baumannii (CR-AB) to be 85.32%. The percentage of antibiotic resistence were 49.54% (amikacin), 56.88%(cefepime), 79.82%(cefotaxime) , 12.84 (cefpopera/sulbactam), 77.98%(ceftazidime), 80.73%(ceftriazone), 81.65%(ciprofloxacin), 64.22%(gentamicin), 85.32%(imipenem), 85.32% (meropenem), 78.90% (piperacillin/tazo- bactam), 69.72%(tetracycline) and 42.20%(trimethoprim/sulfamethoxazole ). All isolates were sensitive to colistin and tigecycline. Class D carbapenemase genes were investigated by multiplex polymerase chain reaction (multiplex-PCR) amplification. Most isolates carried OXA carbapenemase genes, including bla_OXA-51 97.25%, bla_OXA-23 75.32%, bla_OXA-58 7.34%. XDR-AB strains were selected to study the plasmid profiles. Each strain carried two plasmids, ranging in size from 20 to 23 Kb. The bla_OXA23 gene presented in all XDR-AB plasmids. Data obtained from our study showed the evaluation of antibiotic resistance genes in A. baumannii which is necessary to prevent the further spread of antibiotic resistance bacteria.