耐亚胺培南鲍氏不动杆菌carO基因表达的研究

Study on expression of carO involved in imipenem-resistant Acinetobacter baumannii

目的调查鲍氏不动杆菌对亚胺培南的耐药情况,研究鲍氏不动杆菌中carO基因表达与亚胺培南耐药性之间的关系,探索鲍氏不动杆菌对亚胺培南耐药的机制。方法收集西安市6所三级综合医院临床分离的非重复性鲍氏不动杆菌362株,采用K-B法和微量肉汤稀释法分别进行体外亚胺培南药敏试验;PCR法扩增外膜蛋白基因carO;选取carO基因扩增阳性的鲍氏不动杆菌菌株,应用RT-PCR法比较亚胺培南敏感组与耐药组之间carO基因mRNA水平的表达差异。结果 362株鲍氏不动杆菌中共有271株对亚胺培南敏感,敏感率为74.86%;73株耐药,耐药率为20.17%;PCR法检测到鲍氏不动杆菌carO基因的检出率为81.11%;RT-PCR法检测11株亚胺培南敏感菌株和4株耐药菌株中carO基因在mRNA水平的表达,统计结果显示,carO基因在耐药组的表达显著低于敏感组(P<0.05)。结论鲍氏不动杆菌对亚胺培南的耐药性与外膜蛋白基因carO的低表达有关。

OBJECTIVE To investigate the drug resistance of the Acinetobacter baumannii to imipenem in Xi＇an area and study the correlation between the expression of carO gene in A.baumannii and the drug resistance to imipenem so as to explore the drug resistance mechanism of A.baumannii to imipenem.METHODS A total of 362 strains of non-repetitive A.baumannii were collected from six general hospitals in Xi＇an region.The in vitro drug susceptibility testing of imipenem was performed by respectively using K-B method and broth microdilution method;the outer membrane protein gene carO was amplified by PCR.The A.buamannii strains amplified positive for carO gene were collected,then the mRNA expression level of carO gene was compared by RT-PCR between the imipenem-sensitive and imipenem-resistant strains.RESULTS Of totally 362 strains of non-repetitive A.baumannii,there were 271 strains sensitive to imipenem with the susceptibility rate of 74.86% and 73 strains resistant to imipenem with the resistance rate of 20.17%.carO gene was detected in 81.11% of the A.baumannii strains by PCR.By the RT-PCR,the expression of carO＇s mRNA has been detected in 11strains of imipenem-resistant isolates and 4 strains of imipenem-resistant isolates,and the statistical analysis showed that the expression level of carO gene in the imipenem-resistant strains was significantly lower than that in the imipenem-sensitive strains（P0.05）.CONCLUSION The resistance of A.baumannii to imipenem may be related to the low expression of outer membrane protein carO gene.