[作为社区获得性尿路感染病因的大肠杆菌的毒力因子和O血清群]

[Virulence factors and 0 serogroups of Escherichia coli as a cause of community-acquired urinary infections].

作者信息

Blanco M, Blanco J, Blanco J E, Alonso M P, Abalia I, Rodríguez E, Bilbao J R, Umaran A

机构信息

Departamento de Microbiología y Parasitología, Facultad de Veterinaria, Universidad de Santiago.

出版信息

Enferm Infecc Microbiol Clin. 1995 Apr;13(4):236-41.

PMID:7779877

Abstract

BACKGROUND

The aim of this study was to determine the virulence factors and 0 serogroups of E. coli strains that cause community acquired urinary tract infections (UTI).

METHODS

We examined 103 E. coli strains isolated from the urine of patients with UTI. The following virulence factors were investigated using phenotypic techniques: the alpha-haemolysin (Hly), the cytotoxic necrotizing factor type 1 (CNF-1) and the mannose-resistant haemagglutination (MRHA) types III, IVa and IVb expressed by P fimbriated E. coli. Serotyping of 0 antigen was carried out by means of a microtechnique using 163 antisera.

RESULTS

Fifty-five (53%) of the 103 E. coli strains examined showed some of the virulence factors investigated in this study; 41% of the strains were Hly+, 28% were CNF-1+ and 48% expressed MRHA types III, IVa or IVb. The uropathogenic strains characterized belonged to 27 different 0 serogroups. However, 68% were from one of 10 serogroups (01, 02, 04, 06, 09, 018, 027, 073, 075 and 077) and 36% were from one of only 3 serogroups (02, 04 and 06). Furthermore, the virulence factors were concentrated in strains belonging to the 3 serogroups most frequently detected. Thus, 36 (97%) of the 37 strains of these 3 serogroups showed virulence factors, versus only 19 (29%) of 66 belonging to other serogroups (p < 0.001).

CONCLUSIONS

Our results support the special pathogenicity theory and suggest that many cases of community acquired UTI may be caused by a limited number of uropathogenic E. coli strains that produce toxins (Hly+ and/or CNF-1+) and possess P fimbriae or P-related adhesins (with MRHA types III, IVa or IVb), and that usually belong to 02, 04 and 06 serogroups.

摘要

背景

本研究的目的是确定引起社区获得性尿路感染（UTI）的大肠杆菌菌株的毒力因子和O血清群。

方法

我们检测了从UTI患者尿液中分离出的103株大肠杆菌菌株。使用表型技术研究了以下毒力因子：α-溶血素（Hly）、1型细胞毒性坏死因子（CNF-1）以及由P菌毛大肠杆菌表达的III型、IVa型和IVb型甘露糖抗性血凝（MRHA）。通过使用163种抗血清的微量技术进行O抗原血清分型。

结果

在检测的103株大肠杆菌菌株中，有55株（53%）表现出本研究中所调查的一些毒力因子；41%的菌株为Hly+，28%为CNF-1+，48%表达III型、IVa型或IVb型MRHA。所鉴定的尿路致病性菌株属于27个不同的O血清群。然而，68%来自10个血清群之一（O1、O2、O4、O6、O9、O18、O27、O73、O75和O77），36%仅来自3个血清群之一（O2、O4和O6）。此外，毒力因子集中在最常检测到的3个血清群的菌株中。因此，这3个血清群的37株菌株中有36株（97%）表现出毒力因子，而属于其他血清群的66株中只有19株（29%）表现出毒力因子（p<0.001）。