Study on aminoglycosides resistance and its resistance genes in multidrug resistant Acinetobacter baumannii / 国际检验医学杂志

ABSTRACT

Objective To investigate the resistance of multi-drug resistant Acinetobacter baumannii against aminoglycosides and its resistance genes.Methods The minimal inhibitory concentrations (MICs) of seven antimicrobials (gentamicin, amikacin, tobramycine, netilmicin, neomycin, streptomycin and kanamycin) against 20 strains of multi-drug resistant Acinetobacter baumannii were detected by agar dilution method. Meanwhile, two resistance genes of aminoglycoside nucleotidyltransferase were amplified by PCR and vertified by DNA sequencer.Results It was found that MIC50 and MIC90 of gentamicin, amikacin, streptomycin and kanamycin in 20 strains of Acinetobacter baumannii were all above 1 024 mg/L, and their resistant rates were 95%, 95%, 100% and 90% respectively, while the resistant rates of tobramycin, netilmicin and neomycin were 85%, 90% and 40% respectively. Two aminoglycoside-modification genes ant(2″)-Ⅰ and ant(3″)-Ⅰ were detected in 20 strains, with 55% and 80% of positive rate respectively. The double positive rate of two resistance genes was 50%.Conclusion The resistance of multi-drug resistant Acinetobacter baumannii against aminoglycosides was closely associated with ant(2″)-Ⅰ and ant(3″)-Ⅰ genes.