The prevalence of 16S rRNA methylase gene armA and drug resistance in Acinetobacter baumannii

Abstract

Objective To investigate the prevalence of 16S rRNA methylase gene armA and to analyze their effect on the drug resistance in multi drug-resistant strains of Acinetobacter baumannii . Methods A total of 72 Acinetobacter baumannii isolates were collected from the Second Xiangya Hospital from Jan. 2008 to Dec. 2008. The size of inhibitory zone of these strains to gentamycin, tobramycin and amikacin were determinate using Kirby-Bauer( K-B) method. The 16S rRNA methylase genes armA were detected by PCR. PCR products were purified and sequenced. Then we used randomly amplified polymorphic DNA method (RAPD) genotyping technology for the establishment of DNA fingerprinting. In addition, we compared drug sensitivity test with RAPD technology. Results Twenty isolates of 72 strains were armA positive and the resistance rates of the strains with armA gene to gentamycin, tobramycin, amikacin were 90.0% , 90.0% and 90. 0% , respectivily. armA positive stains were divided into 7 types using RAPD technology. A genotype was the advantage type. Conclusion The study showed that 16S rRNA methylases gene armA was prevalent in Acinetobacter baumannii which could lead to resistant to almost all aminoglycosides at a high level. And the main form of armA gene prevalence in our hospital was the spread of the same clone strain inside and outside of clinic department. Key words: Acinetobacter baumannii; 16S rRNA methylase genes; Drug resistance; armA gene