Genotype and drug resistance of OXA-51-like carbapenemases in Acinetobaeter baumannii / 中华检验医学杂志

ABSTRACT

Objective To study the genotypes of OXA-51-like carbepenemases in Aeinetobacter beumannii and its association with drug resistance. Methods The susceptibility of 174 Acinetobacter baumannii against ceftazidime, cefotriaxon, amikacin and ciprofloxacin were detected with disc diffusion method. The minimum inhibitory concentration (MIC) values for meropenem and imipenem were determined with an agar dilution method. VIM, IMP, OXA-23, OXA-24, OXA-51 and OXA-58 β-lactamase genes were determined by PCR. DNA sequencing and genotyping were performed against OXA-51 positivestrains. Results All 174 isolates were negative by PCR for genes OXA-24, OXA-58, IMP and VIM. OXA-23 and OXA-51were amplified in 15.5% (27/174) and 72.4% (126/174) isolates, respectively. Therewere 15.5% (27/174) isolates producing OXA-51-like and OXA-23 carbapenemase simultaneously. Among126 OXA-51-like carbapenemase producing strains, 82.5% (104/126)were OXA-66 genotype, whereas theremaining 17.5% (22/126) strains belong to other genotype. Eight novel OXA-51-like Genotype were foundin this study. Conclusions OXA-66 were the primary genotype of OXA-51-like carbapenemases in A.baumannii. OXA-66 were related to low-level carbapenems resistance and may be associated with resistanceof other drugs. We found new OXA-51-like genotype in clinic isolates of A. baumannii in this study.