›› 2012, Vol. 27 ›› Issue (2): 103-109.

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The study on Acinetobacter baumannii beta-lactamases in four hospitals of Shanghai

  

  1. 1. Department of Clinical Laboratory, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China; 2. Department of Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China;3. Department of Clinical Laboratory, East Hospital, Tongji University, Shanghai 200120, China;4. Department of Clinical Laboratory, Shanghai Pudong New Area Gongli Hospital,Shanghai 200135,China;5.Shanghai D.A Medical Laboratory Co.,LTD.,Shanghai 200433, China
  • Online:2012-02-28 Published:2012-02-19

Abstract: Objective To understand the resistance to 13 antibiotics and beta-lactamase genes in Acinetobacter baumannii in Shanghai 4 hospitals in 2010, and investigate the epidemic types, so as to provide the reference for rational use of antibiotics and control of nosocomial infections. Methods The 204 isolates of Acinetobacter baumannii were collected from clinical specimens of 4 hospitals. Agar dilution was performed to determine the minimum inhibitory concentrations (MIC) to 13 antibiotics. Three dimensional extract test and ethylene diamine tetraacetic acid (EDTA) disc were carried out to screen AmpC enzyme and metal enzyme, respectively. OXA-23,OXA-24,OXA-51,OXA-58,ampC,IMP-1,IMP-4 and VIM-2 coding genes were amplified by polymerase chain reaction (PCR). Results The resistance rates of these strains to ciprofloxacin,piperacillintazobactam,cefoxitin,sulfamethoxazole and cefoperazone were higher than 90%. The resistance rates of strains to levofloxacin and polymyxin B were relatively low. The resistance rates of the hospitals in Pudong to meropenem, levofloxacin and polymyxin B were higher than those of the hospitals in Puxi. The results of the three dimensional extract test showed that the positive rate of Gongli Hospital was the highest (84.6%), and the positive rate of Ruijin Hospital was the lowest (42.3%). The results of metal enzyme phenotype testing showed that Gongli Hospital and Renji Hospital(West) did not detect the positive strains of metal enzyme phenotype, in the other 3 hospitals, the highest positive rate (27.3%) was detected in East Hospital,and the positive rate of Ruijin Hospital was the lowest (7.7%). The results of PCR amplification showed that the positive rate of Pudong hospitals was higher than that of Puxi hospitals for OXA-23 and ampC. OXA-51 were all positive in all strains,and OXA-24,OXA-58 and IMP-1 were all negative. IMP-4 and VIM-2 were detected at Renji Hospital(East) and East Hospital,while they were not detected in Gongli Hospital, Ruijin Hospital and Renji Hospital(West). Conclusions OXA-51 is detected in the isolates of Acinetobacter baumannii, and there is slight difference between different hospitals in the mechanism of Acinetobacter baumannii beta-lactamases.

Key words: Acinetobacter baumannii, Bacterial resistance, Beta-lactamase