Abstract:

Objective To investigate the drug resistance genes and susceptibility of 96 clinically isolated strains of Acinetobacter baumannii resistant to imipenem and meropenem. Methods Carbapenemase phenotype analysis was performed on 96 clinically isolated strains of carbapenem ⁃ resistant Acinetobacter baumannii，PCR amplification and electrophoresis imaging analysis of drug⁃resistant genes were performed，and drug sensitivity tests were conducted to analyze the sensitivity of the isolates to piperacillin/tazobactam and other 15 drugs. Results The samples were mainly obtained from lower respiratory tract（59 strains，61.5%），venous blood（18，18.75%）， and drainage fluid（8，8.3%）and from ICU（75 strains，78%），rehabilitation medicine department（5，5.2%）， and neurology department（5，5.2%）. 69 strains（approximately 71.9%）were positive in modified Hodge test. The enzyme inhibition test was not consistent with phenotype，and there was compound resistance mechanism. The bacteria was 100% resistance to ticacillin/clavulanate，piperacillin/tazobactam and ciprofloxacin；and 83.3% to cotrimoxazole，85.4% to cefepime，88.4% to tobramycin，91.7% to cefoperazone/sulbactam，96.9% to levofloxacin， 98.9% to doxycycline，99.0% to ceftazidime，1.1% to polymyxin，4.2% to tegacycline，and 36.8% to minocycline. Drug resistance gene OXA ⁃23 was detectable in 95 strains，OXA ⁃51 in 93 and KPC in 3，while other resistant genes were not found. Conclusions Carbapenem⁃resistant Acinetobacter baumannii showed multi⁃drug resistance and pan⁃drug resistance. OXA⁃23 and OXA⁃51 genes were the main drug resistance genes of carbapenemase in our hospital.

Key words: Acinetobacter baumannii, carbapenemase, drug sensitivity, resistance genes