医院感染铜绿假单胞菌脉冲场凝胶电泳分析

Analysis of nosocomial infectionds caused by Pseudomonas aeruginosa using pulsed-field gel electrophoresis

目的确定铜绿假单胞菌不同基因型与抗菌谱的联系,以追踪院内感染中铜绿假单胞菌菌株在分子水平上的相关性。方法对2002年1月～2004年12月自该院住院患者各种标本中分离获得216株铜绿假单胞菌,用脉冲场凝胶电泳分析耐亚胺培南铜绿假单胞菌的同源性;液体稀释法测定携带blaIMP基因铜绿假单胞菌菌株的最小抑菌浓度,纸片扩散法检测亚胺培南敏感株和耐药株对10种常用抗菌药物的耐药性。结果分离的铜绿假单胞菌主要来自呼吸道标本,对常用抗菌药物的耐药率高,多重耐药现象严重。携带blaIMP基因与不携带blaIMP基因的铜绿假单胞菌对亚胺培南的耐药性差异有显著性,未携带blaIMP基因的铜绿假单胞菌菌株在PFGE上表现出不同的分型,而携带blaIMP基因的10株中9株具有相同的PFGE分型。结论blaIMP基因在铜绿假单胞菌的耐药机制中起主要作用,了解铜绿假单胞菌的耐药现状,有利于为临床合理用药提供依据,抗生素的合理使用可减少细菌耐药性的产生,降低医院感染的发病率。

[Objective] To determine the association of different genotypes with the antibiograms in order to track the spread of nosocomial infections caused by genetically related strains.[Methods] From Jan,2002 to Dec,2004,216 Pseudomonas aeruginosa（P.a.）isolates were obtained from different clinical samples.Susceptibility against antibiotics was determined by Kirby-Bauer disc diffusion method.and dilution test.Homology of imipenem-resitstant Pseudomonas aeruginosa was analyzed using pulse-field gel electrophoresis.[Results] Widely variable PFGE patterns were found among blaIMP-free strains while 9 from the 10 blaIMP-carried strains demonstrated the same PFGE patterns.The respiratory tract was the commonest source of Pseudomonas aeruginosa.Of the 216 isolats,the resistance rates against common antibacterial were considerably high and many demonstrates multi-drug resistance.Significant difference existed between P.a strains with and without blaIMP gene in resistance to imipenem.[Conclusions] The status of resistance of Pseudomonas aeruginosa must be investigated,in order to provide evidence for clinical drug utilization.