耐亚胺培南的铜绿假单胞菌整合子基因研究

Integrons analysis in imipenem-resistant clinical strains of Pseudomonas aeruginosa

目的通过分析耐亚胺培南的铜绿假单胞菌的整合子所携带的耐药基因的种类及特点,探讨其耐药机制,为指导临床用药,预防院内感染和流行病学调查、新药的研发提供参考。方法根据美国国家临床标准化研究所(CLSI/NCCLS)2004年标准,应用纸片扩散法(KB)进行药敏试验,采用多重PCR方法对临床分离的23株耐亚胺培南的铜绿假单胞菌进行整合酶(IntI)检测,并分析整合酶阳性菌株的耐药基因盒。结果药敏试验显示23株耐亚胺培南的铜绿假单胞菌全部为泛耐株,5株为Ⅰ类整合酶阳性,其中3株为缺失型,无耐药基因盒,其余2株耐药基因为blaVIM4和blaPSE-1;14株为Ⅱ类整合酶阳性,其耐药基因盒均为dfr1-sat1-aadA1;3株Ⅰ、Ⅱ类整合酶均为阳性;7株不含Ⅰ、Ⅱ类整合酶。结论耐亚胺培南的铜绿假单胞菌大多都具备Ⅰ、Ⅱ类整合酶基因和基因盒,这是造成它们成为泛耐株的重要耐药机制。

Objective Resistance mechanism of 23 imipenem-resistant Pseudomonas aeruginosa strains was studied by analyzing the category and the characteristic of their integron resistance gene cassette, in order to give clinical treatment guidance, prevent nosocomial infection and offer data for epidemiology investigation. Methods The antibiotic susceptibility tests of 23 imipenem-resistant Pseudomonas aeruginosa strains were performed by Kirby-bauer method, muhi-PCR was used to detect integrase gene（intI） of them, and positive strains were further analyzed for their resistance gene cassette. Results Susceptibility experiments suggested that all of 23 strains were Pan-resistant strains. Of them, 2 strains were detected as intI1-positive; 11 strains were detected as intI2-positive; 3 strains were found carrying intI1 and intI2 gene; 7 strains were negative in muhi-PCR. Of intI1-positive strains, 3 strains were found no gene cassette, others were found possessing an blaVIM-4 and blaPSE-1 gene cassette, intI2-positive strains were all found an dfrl-satl-aadA1 gene cassette. Conclusion Most of all imipenem-resistant Pseudomonas aeruginosa was found carrying intI1 and intI2 gene and resistance gene cassette, which was a very important resistant mechanism as Pan-resistant strains.