泌尿系感染产ESBLs株耐药基因分型及药敏试验

ESBLs Producing Clinical Isolates from Urinary System:Their Genotype and Antibiotic Resistance

目的了解泌尿系感染产超广谱β-内酰胺酶(ESBLs)菌株的主要基因型分布特点及其耐药性。方法用表型确证试验确定临床尿液标本中,产ESBLs的大肠埃希菌和肺炎克雷伯菌54株,分别用TEM、SHV和CTX-M通用引物进行聚合酶链反应(PCR),用琼脂稀释法测定其最低抑菌浓度(MIC),并对结果进行分析。结果PCR扩增结果显示:CTX-M、TEM和SHV的检出率分别为85.2%、37.0%和9.3%,42.6%的菌株同时携带≥2个基因;MIC测定结果显示:产ESBLs株对亚胺培南的敏感率为100%;对阿米卡星的敏感率高达98.1%;对哌拉西林/他唑巴坦和头孢西丁的敏感率也较高,分别为88.9%和70.4%;其对环丙沙星和氨苄西林/舒巴坦的敏感率则低,分别为25.9%和1.9%。结论我院泌尿系感染产ESBLs株对亚胺培南的敏感性最高,接近半数菌株同时携带≥2个基因,产ESBLs菌株的主要基因型为CTX-M。

OBJECTIVE To understand the characters of genotyping and antibiotic resistance of strains producing extended spectrum beta-lactamases （ESBLs） isolated from urinary system. METHODS ESBLs producing Escherichia coli and Klebsiella pneumoniae strains that isolated from urine were identified by phenotypic confirmatory test. The presence of the TEM, SHV and CTX-M genes was confirmed by specific PCR assays.MICs to the isolates were determined by the agar dilution method. RESULTS The genotype of the isolates was as follows：. 85.2％ CTX-M,37.0％ TEM and 9.3％ SHV . Near half （46.2％） of the strains carried more than one type of ESBLs gene. MIC test showed these strains were 100％ susceptible to imipenem, 88.9％ to amikacin,70.4％ to piperacillin/tazobactam. However, the susceptibility to ciprofloxacin and ampicillin/sulbactam was very low （25.9 and 1.9％, respectively）. In addition, 88.2％ strains showed nonsusceptible to cefotaxime.CONCLUSIONS In our hospital, ESBLs producing isolates are most susceptible to imipenem, about half of the strains carry more than one ESBLs gene, the major genotype of ESBLs producing isolates is CTX-M.