Andrade J R, Suassuna I
Serviço de Microbiologia e Imunologia, Faculdade de Ciências Médicas, UERJ, Brasil.
Mem Inst Oswaldo Cruz. 1988 Apr-Jun;83(2):193-9. doi: 10.1590/s0074-02761988000200008.
Fifty nine Escherichia coli strains obtained from patients with upper or lower urinary tract infections (UTI) and 30 E. coli strains isolated from stools of healthy individuals were tested for hemolytic and cytotoxic activities. Forty four percent of uropathogenic E. coli (UPEC) and 3.3% of fecal E. coli were hemolytic. Among the hemolytic UPEC, 92% produced alpha-hemolysin. A cytotoxic activity was detected in culture filtrates of 71% of UPEC strains and 30% of fecal E. coli. No relationship was found between cytotoxic and hemolytic activities or between cytotoxic titers and UPEC origin (upper or lower UTI). E. coli cytotoxin has a cytocidal activity against some epithelioid cultured cell lines (Vero, HeLa and Hep-2) but was almost inactive for avian-fibroblast cells. Cytotoxin-affected cells appeared rounded, refractile and detached from the surface of the vessel. Some characteristics exhibited by the cytotoxin as the morphological response induced on cells, the increasing of cytopathic effect with time, its irreversible cytocidal activity and its heat-lability resemble the properties described for E. coli Verotoxin (VT). Adherence to uroepithelial cells is recognized as a virulence factor for UPEC. It is suggested that cell damage by cytotoxic and adhering UPEC might contribute to E. coli virulence to urinary tract.
对从患有上尿路感染或下尿路感染（UTI）的患者中分离出的59株大肠杆菌菌株以及从健康个体粪便中分离出的30株大肠杆菌菌株进行了溶血和细胞毒性活性测试。44%的尿路致病性大肠杆菌（UPEC）和3.3%的粪便大肠杆菌具有溶血活性。在具有溶血活性的UPEC中，92%产生α-溶血素。在71%的UPEC菌株和30%的粪便大肠杆菌的培养滤液中检测到细胞毒性活性。在细胞毒性和溶血活性之间或细胞毒性滴度与UPEC来源（上尿路感染或下尿路感染）之间未发现相关性。大肠杆菌细胞毒素对一些上皮样培养细胞系（Vero、HeLa和Hep-2）具有杀细胞活性，但对禽成纤维细胞几乎无活性。受细胞毒素影响的细胞呈现圆形、折光性并从容器表面脱落。细胞毒素表现出的一些特征，如对细胞诱导的形态学反应、细胞病变效应随时间增加、其不可逆的杀细胞活性及其热不稳定性，类似于大肠杆菌志贺毒素（VT）所描述的特性。对尿道上皮细胞的粘附被认为是UPEC的一种毒力因子。有人提出，细胞毒性和粘附性UPEC对细胞的损伤可能有助于大肠杆菌对泌尿道的毒力。
