尿路致病性大肠埃希菌1型菌毛黏附特性与分子流行病学分析

Adhesion characteristics and molecular epidemiology of uropathogenic Escherichia coli

目的了解尿路致病性大肠埃希菌(UPEC)1型菌毛黏附特性、耐药表型及分子流行病学特征,为临床诊疗提供理论基础。方法收集2020年1-11月广东省中医院大学城医院临床分离的80株UPEC,利用VitekⅡ细菌鉴定药敏分析仪鉴定细菌并进行药敏实验。利用PCR方法检测UPEC的1型菌毛fimH基因的携带情况,酵母细胞黏附实验检测UPEC的黏附特性,比较黏附阳性UPEC和黏附阴性UPEC菌株间的抗生素耐药差异。通过随机扩增多态性DNA(RAPD)法分析黏附阳性UPEC间的亲缘关系。结果80株UPEC中1型菌毛fimH基因阳性菌株为74株,占94.5%,其中黏附阳性菌株为37株,占50.0%。黏附阳性UPEC头孢呋辛耐药率(45.9%)和产超广谱β内酰胺酶(ESBL)阳性率(45.9%)均高于黏附阴性UPEC(21.6%、21.6%),差异均有统计学意义(P均<0.05)。37株黏附阳性UPEC可基因聚类,分为18个基因型,其中以R010基因型为主,包含11株UPEC,占29.7%;另外R006基因型包含4株UPEC,占10.8%;其余基因型均包含1~2株菌。结论临床分离的UPEC 1型菌毛fimH基因携带率高,黏附能力强,应用头孢呋辛抗感染治疗时应注意耐药。黏附阳性菌株虽可聚类,但未出现院内流行性感染趋势。

Objective To understand the fimbriae adhesion characteristics,drug resistance phenotype and molecular epidemiological characteristics of uropathogenic Escherichia coli(UPEC)type 1,and provide a theoretical basis for clinical diagnosis and treatment.Methods A total of 80 strains of UPEC isolated from the Guangdong Provincial Hospital of Traditional Chinese Medicine from January to November 2020 were collected.The bacteria were identified by Vitek Ⅱ bacterial identification and drug sensitivity analyzer.PCR method was used to detect the carrying rate of fimH gene of UPEC;yeast cell adhesion test was used to detect the adhesion characteristics of UPEC,and the difference of antibiotic resistance between adhesion positive UPEC and adhesion negative UPEC strains was compared.The genetic relationship in adhesion positive UPEC was analyzed by random amplified polymorphic DNA(RAPD).Results Among the 80 strains of UPEC,74 strains were positive for fimH gene of type 1 pili,accounting for 94.5%;of which,37 strains were positive for adhesion,accounting for 50.0%.The cefuroxime resistance rate(45.9%)and the positive rate of extended-spectrumβ-lactamase(ESBL)(45.9%)of adhesion positive UPEC were significantly higher than those of adhesion negative UPEC(21.6%,21.6%),the differences were statistically significant(P all<0.05).The adhesion positive UPEC were clustered and divided into 18 genotypes;of which,R010 genotype was the main genotype,including 11 UPEC,accounting for 29.7%.In addition,R006 genotype contained 4 strains of UPEC,accounting for 10.8%,and the other genotypes contained 1-2 strains.Conclusions UPEC had high carrying rate of fimH gene of type 1 pili and strong adhesion ability.Drug resistance should be paid attention to when using cefuroxime in anti-infection treatment.Although the adhesion positive strains could be clustered,there was no trend of nosocomial epidemic infection.