合肥地区铜绿假单胞菌Ⅲ型分泌系统毒力基因检测分析

Detection of typeⅢsecretion system virulence-related genes in Pseudomonas aeruginosain Hefei

目的了解合肥地区铜绿假单胞菌Ⅲ型分泌系统(TTSS)毒力基因ExoS和ExoU的携带情况及分布耐药特点。方法收集合肥地区2所三甲医院2013年1月-2015年1月临床分离的156株铜绿假单胞菌,使用VITEK-2Compact系统进行菌株鉴定和药敏试验,采用PCR法检测exoS、exoU毒力基因。结果 156株铜绿假单胞菌中有129株携带TTSS,其中exoU-/exoS+基因表型菌株为99株,占总阳性菌株76.7%,exoU+/exoS-基因表型菌株为21株,占总阳性菌株16.3%,exoU-/exoS-基因表型菌株为9株,占总阳性菌株6.98%;痰液标本和血液标本均以exoU-/exoS+基因表型最常见;药敏试验分析,TTSS阴性菌株对头孢哌酮/舒巴坦、头孢吡肟、亚胺培南、哌拉西林、环丙沙星的耐药性均高于TTSS阳性菌株(P<0.05);exoU-/exoS+菌株和exoU+/exoS-菌株的药敏试验结果相似。结论大多数铜绿假单胞菌中存在TTSS,且以exoU-/exoS+基因表型菌株为多;检测菌株exoU、exoS基因对临床诊断和抗菌药物合理运用有一定指导意义。

OBJECTIVE To understand the carrying rates of type Ⅲ secretion system （TTSS） virulence-related genes ExoS and ExoU in Pseudomonas aeruginosa strains in Hefei and analyze the characteristics of drug resistance. METHODS A total of 156 strains of P. aeruginosa were isolated from two three-A hospitals in Hefei from Jan 2013 to Jan 2015, the strains were identified by using VITEK-2 Compact system, the drug susceptibility testing was performed, and the virulence genes exoS, exoU were detected by means of PCR. RESULTS Of the 156 strains of P. aeruginosa, 129 carried with TTSS, of which 99 （76.7%） carried with exoU-/exoS＋ gene phenotype, 21 （16.3%） carried with exoU＋/exoS- gene phenotype, and 9 （6.98%） carried with exoU-/exoS- gene phenotype. The exoU-/exoS＋ gene phenotype was the most common in the sputum and blood specimens. The result of the drug susceptibility testing showed that the drug resistance rates of the TTSS-negative strains to cefoperazonesulbactam, cefepime, imipenem, piperacillin, and ciprofloxacin were higher than those of the TTSS-positive strains （all P〈0.05）. the result of drug susceptibility testing of the strains carrying with exoU-/exoS＋ was similar to that of the strains carrying with exoU＋/exoS-. CONCLUSION Most of the P. aeruginosa strains carry with TTSS genes, and the exoU-/exoS＋ gene phenotype is dominant. The detection of the exoU, exoS genes may have certain guiding significance in clinical diagnosis and reasonable use of antibiotics.