Abstract

This study aimed to investigate the existence and molecular epidemiological characteristics of  multi-drug resistant Acinetobacter baumannii (MDRAB)-related resistance genes isolated from our hospital. Microdilution and disk diffusion methods were used to detect the antibiotic susceptibility of 46 MDRAB isolates that carried OXA-51 gene. Pulsed-field gel electrophoresis (PFGE) was used to analyze the homologies among the strains. Resistance genes were tested through polymerase chain reaction. Among the 46 MDRABA, a total of nine, isolates were categorized as strain A (19.6%), eight as strain B (17.4%), and four as strain O (8.7%). A total of 41 isolates (89.1%) carried the OXA23 gene, 17 (37.0%) carried the PER gene, and six (13%) carried the IMP gene. Six strains (13%) did not carry the membrane pore protein gene carO. The numbers of isolates that carried a particular gene were as follows: 40 (87.0%), armA; 41 (89.1%), ant(3”)-I; 33 (71.7%), aac(3)-I; 2 (4.3%), aac(3)-II; 1 (2.2%), aac(6’)-II; and 1 (2.2%) and aph(3’)-VI. Most of the isolates (93.5%) carried the qacE∆1 gene. These hospital MDRAB isolates were proven to simultaneously carry a variety of drug resistance genes. Strains A and B were the major epidemic strains of nosocomial MDRAB.

Key words: Acinetobacter baumannii, resistance gene, pulsed-field gel electrophoresis, multi-drug resistant.