下呼吸道感染产ESBLs肺炎克雷伯菌基因型分析

Genotype analysis of ESBLs-producing Klebsiella pneumoniae causing lower respiratory tract infection

目的了解引起下呼吸道感染产 ESBLs 肺炎克雷伯菌的耐药性及 ESBLs 和 AmpC 基因型,指导临床合理用药。方法收集产 ESBLs 肺炎克雷伯菌36株。用纸片扩散法进行药敏性试验,表型筛选法检测出同时产 AmpC 酶的菌株,PCR 法检测 ESBLs 和 AmpC 酶的基因型。结果产 ESBLs 肺炎克雷伯菌对亚胺培南和美罗培南全部敏感,对所测试的其他药物呈不同程度耐药。36株产 ESBLs 肺炎克雷伯菌中,20株扩增出 CTX-M-Ⅲ群基因,15株扩增出 TEM 基因,SHV 和 OXA 基因各1株,ACT-1(MIR-1)和 DHA-1(DHA-2)各4株,12株细菌同时携带2种以上的基因型。结论本院下呼吸道感染患者中分离的产 ESBLs 肺炎克雷伯菌主要携带 CTX-M 和 TEM 基因型,少数携带 ACT、DHA、SHV 和 OXA 基因型,可介导对β内酰胺类药物的耐药。本研究未对 TEM 和 SHV 基因型作进一步分析。

Objective To investigate the antimicrobial resistance of ESBLs producing Klebsialla pneumonia isolated from lower respiratory tract infection and ESBLs and AmpC genotypes for rational antimicrobial therapy. Methods Thirty-six strains of ESBLs-producing K. pneumonia were collected. Antibiotic susceptibility was tested by agar dilution. AmpC producing strains were detected by phenotype screening method. The genes of ESBLs and AmpC were amplified by polymerase chain reaction （PCR）. Results All of the 36 strains of ESBLs producing K. pneumonia were susceptible to imipenem and meropenem, resist ant variably to other antimicrobial agents tested. CTX-M-Ⅲ-group was identified in 20 strains, TEM type in 15 strains; SHV type and OXA type in 1 strain each, ACT-1（MIR-1） type in 4 strains, and DHA-1 （DHA-2）-type in 4 strains. Twelve strains contained more than 2 genotypes simultaneously. Conclusions The ESBLs-producing K. pneumonia isolated from patients with low respiratory tract infection in this hospital mainly contains the genotypes of CTX M and TEM.Genotypes of ACT, DHA, SHV and OXA are also identified. These genotypes are responsible for the resistance to beta-laetams.