CLINICAL USE OF MOLECULAR EPIDEMIOLOGY FOR NOSOCOMIAL IMIPENEMRESISTANT PSEUDOMONAS AERUGINOSA INFECTIONS

为了阐明铜绿假单胞菌（P.aeruginosa）医院感染基因分型的临床应用，我们研究了在我们的外科病房分离的亚胺培南耐药铜绿假单胞菌（伊尔帕）的基因分型和血清分型。对1987 ~ 1998年临床分离的428株铜绿假单胞菌，分别采用玻片凝集试验和脉冲场凝胶电泳（PFGE）进行血清分型和基因分型。根据NCCLS指南测定亚胺培南的耐药性。总体而言，伊尔帕感染的发生率为21.5%。伊尔帕感染的年发病率在1990、1991和1994年特别高（34-47%）。血清学上，F组菌株在1990年和1991年之间流行，B组菌株在1994年流行。在PFGE分析中，F组菌株显示出相同的模式，而B组菌株检测到三种模式，表明这些暴发是医院感染。1995年后，通过适当使用碳青霉烯类抗生素，伊尔帕感染的发生率降低（14.6%），血清分型和PFGE分析均未发现明显的暴发。然而，从数字化PFGE模式的计算树状图显示，一些零星的医院感染限于“病人到病人”。虽然血清分型可以提倡检测医院感染的爆发。PFGE可用于医院感染暴发前的“病人-病人”有限感染调查。

To elucidate the clinical use of genotyping for nosocomical infections of Pseudomonas aeruginosa (P.aeruginosa), we examined genotyping and serotyping of imipenem-resistant Pseudomonas aeruginosa (IRPA) isolated in our surgical ward. In 428 P.aeruginosa strains clinically isolated from the patients between 1987 and 1998, serotyping and genotyping were performed by the slideagglutination test and pulsed-field gel electrophoresis (PFGE), respectively. Suseeptibility ageinst imipenem was determined according to the NCCLS guidelines. Overall, the incidence of IRPA infection was 21.5%. The annual incidences of IRPA infections were particularly high in 1990, 1991 and 1994 (34-47%). Serologically, group-F strains were prevalent between 1990 and 1991, and group-B strains in 1994. In PFGE analysis, the identical pattern was shown in group-F strains, and three patterns were detected for group-B strains, suggesting that these outbreaks raged as nosocomial infections. By appropriate use of carbapenem antibiotics after 1995, the incidence of IRPA infections was reduced (14.6%) and neither serotyping nor PFGE analysis detected distinct outbreaks. However, computed dendrogram derived from digitized PFGE patterns revealed some sporadic nosocomial infections limited to "patient-to-patient". Although serotyping can be advocated for detecting outbreaks of nosocomial infections. PFGE may be useful for survey of "patient-to-patient" limited infection before outbreaks of nosocomial infections.