老年人尿路感染大肠埃希菌遗传谱系分型及其耐药性研究

A study of Escherichia coli phvlo-enetic groups and antimicrobiai resistance in elderlv urinary tract infections

的 研究老年人尿路感染大肠埃希菌遗传谱系分型与4种常用抗生素耐药性间的关系. 方法 收集天津市3所综合性医院133株老年尿路感染的大肠埃希菌临床分离院内感染株,菌株的药敏试验采用Kirby-Bauer（K-B纸片扩散法）；用煮沸法提取菌株DNA;采用两步三重聚合酶链式反应（PCR）技术对菌株进行遗传谱系分型. 结果 133株老年人尿路感染的大肠埃希菌,对抗生素耐药率最高的是左氧氟沙星占54.1％（72株）,最低的是哌拉西林和（或）他唑巴坦占15.0％（20株）,差异有统计学意义（Z=51.57,P＜0.01）；遗传谱系分型中A型、B1型、B2型、D型的检出率分别为33株（24.8％）、20株（15.0％）、24株（18.0％）和56株（42.1％）,D型与其他类型比较,差异有统计学意义（Z=31.23,P＜0.01）.遗传谱系B2型菌株多见于左氧氟沙星敏感株,耐药株、敏感株分别为29.5％（18/61）、8.3％（6/72）,差异有统计学意义（x2=10.01,P＜0.01）,D型菌株多见于左氧氟沙星耐药株,分别为31.1％ （19/61）与51.4％（37/72）,差异有统计学意义（x2=5.55,P＜0.05）；未发现大肠埃希菌4个基因型与其他3种抗生素耐药性有关（均P＞0.05）. 结论 遗传谱系分型中D型检出率最高,与左氧氟沙星耐药相关,通过遗传谱系分型可初步判断老年人尿路感染的大肠埃希菌的耐药性.

Objective To study the relationship between Escherichia coli （E.coli.） phylogenetic groups and the antimicrobial resistance in elderly patients with urinary tract infections.Methods 133 Escherichia coli were collected from elderly patients with urinary tract infections in 3 general hospitals in Tianjin.Kirby Bauer method was used to test susceptibility of E.coli.to four antibiotics.Escherichia coli DNA was extracted by boiling method.Phylogenetic groups （A,B1,B2 and D） of the E.coli was isolated by the two-step triplex-PCR.Results In all the strains,levofloxacin resistance rate was the highest （54.1%,72 strains）,piperacillin/tazobactam resistance rate was the lowest （15.0%,20 strains） （Z=51.57,P〈0.01）.The detection rates of Escherichia coli phylogenetic group A,B1,B2 and D were 24.8% （33 strains）,15.0% （20 strains）,18.0% （24 strains）,42.1%（56 strains） （Z=31.2,P〈0.01）.Levofloxacin-sensitive strains were more common in Escherichia coli phylogenetic group B2 strains,and there was a significant difference in the strain number between the resistant and sensitive strains [29.5% （18/61） vs.8.3% （6/72）,x2 =10.01,P〈0.01].Levofloxacin-resistant strains were more common in Escherichia coli phylogenetic group D strains,and there was a significant difference in the strain number between the resistant and sensitive strains [31.1% （19/61） and 51.4 % （37/72）,x2 =5.55,P〈0.05].There was no significant relationship between the Escherichia coli phylogenetic groups and the other three antibiotic resistance （all P〉0.05）.Conclusions The detection rates of group D are the highest in the Escherichia coli phylogenetic groups,and it has a relationship with levofloxacin resistant.The antimicrobial resistance can be estimated by phylogenetic analysis in elderly patients with E.coli urinary tract infections.