多药耐药铜绿假单胞菌产金属β-内酰胺酶的检测

Detection of Metallo-β-lactamase in Multi-resistant Pseudomonas aeruginosa

目的分析多药耐药铜绿假单胞菌临床分离株中金属β-内酰胺酶的产生情况,并对其检测方法进行评价。方法按Aloush等的推荐标准,用K-B法对临床分离的铜绿假单胞菌进行多药耐药株的筛选,双重底物双重酶抑制剂的纸片协同法对多药耐药的铜绿假单胞菌进行产金属β-内酰胺酶表型检测,用PCR方法进行金属β-内酰胺酶IMP、VIM基因型的检测。结果1081株铜绿假单胞菌临床分离株中共筛选出192株多药耐药株;药敏结果显示,多药耐药株对环丙沙星和哌拉西林的耐药率最高,为92.5%,其次为氨曲南和复方新诺明,为91.5%,对多黏菌素全部表现为敏感;该192株多药耐药株中共检出67株金属β-内酰胺酶表型阳性,其中65株扩增出IMP或VIM基因。结论多药耐药铜绿假单胞菌的耐药机制呈复杂化、多样化表现,临床实验室应加强对此类菌株产金属β-内酰胺酶的检测。

OBJECTIVE To investigate the production of metallo-beta-lactamase in clinical isolates of multi-resistant Pseudomonas aeruginosa and evaluate the validity of the detection methods.METHODS The multi-resistant strains were selected by K-B method according to the standard Aloush et al recommended.The metallo-beta-lactamase phenotypes were detected by multi-disk-multi-inhibitors synergy test（MDMIST）,and the genotypes of IMP and VIM gene were analyzed by PCR amplification.RESULTS A total of 192 strains of multi-resistant P.aeruginosa were selected from 1081 clinical strains.The antimicrobial agents test in these multi-resistance strains demonstrated that ciprofloxacin and piperacillin had the highest resistant rate（92.5%）,and the next were aztreonam and trimethoprim-sulfamethoxazole（91.5%）,the polymyxin showed sensitive in all of these strains.Sixty-seven strains of metallo-beta-lactamase phenotypes were positive and the amplification PCRs showed that 65 strains were IMP or VIM in these 192 multi-resistant strains.CONCLUSIONS The resistance mechanisms in multi-resistant P.aerugionsa present multiple and changeable.The clinical laboratory should enhance the detection of metallo-beta-lactamase in these multi-resistant strains.