Background: Shiga toxin-producing Escherichia coli (STEC) has been identified as an important etiologic agent of human disease in Egypt. Aims: To investigate the occurrence and describe the characterization as well as prevalence of STEC in Greater Cairo hospitals as well as molecular characterization of virulence and resistance genes. Methods: Four hundred seventy E. coli clinical isolates were collected from eight hospitals and analyzed by genotypic and phenotypic methods for STEC, followed by histopathological examination and scoring of different organs lesions. Results: The highest proportion of isolates was from urine (151 isolates), whereas the lowest was from splenic drain (3 isolates). In tandem, when serogrouping was performed, 15 serogroups were obtained where the most prevalent was O157 and the least prevalent was O151. All isolates were positive when screened for identity gene gad A, while only typable strains were screened for seven virulence genes stx1 (gene encoding Shiga toxin 1), stx2 (gene encoding Shiga toxin 2), tsh (gene encoding thermostable hemagglutinin), eaeA (gene encoding intimin), invE (gene encoding invasion protein), aggR (gene encoding aggregative adherence transcriptional regulator), and astA (aspartate transaminase) where the prevalence was 48%, 30%, 50%, 57%, 7.5%, 12%, and 58%, respectively. Of 254 typable isolates, 152 were STEC carrying stx1 or stx2 genes or both. Conclusions: Relying on in vivo comparison between different E. coli pathotypes via histopathological examination of different organs, E. coli pathotypes could be divided into mild virulent, moderate virulent, and high virulent strains. Statistical analysis revealed significant correlation between different serogroups and presence of virulence genes.

中文翻译：

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大开罗地区产志贺毒素大肠杆菌临床分离株的流行率和毒力体内评估。

背景：产志贺毒素大肠杆菌（STEC）已被确定为埃及人类疾病的重要病原体。目的：调查大开罗医院 STEC 的发生情况并描述其特征和患病率，以及毒力和耐药基因的分子特征。方法：从8家医院采集470株大肠杆菌临床分离株，采用STEC基因型和表型方法进行分析，并对不同器官病变进行组织病理学检查和评分。结果：比例最高的分离株来自尿液（151 个分离株），而最低比例来自脾引流（3 个分离株）。同时，当进行血清分型时，获得了 15 个血清组，其中最流行的是 O157，最不流行的是 O151。所有分离株在筛选同一基因 gad A 时均呈阳性，而仅筛选可分型菌株的 7 个毒力基因 stx1（编码志贺毒素 1 的基因）、stx2（编码志贺毒素 2 的基因）、tsh（编码热稳定血凝素的基因）、eaeA（编码 intimin 的基因）、invE（编码入侵蛋白的基因）、aggR（编码聚合粘附转录调节因子的基因）和 astA（天冬氨酸转氨酶），其患病率分别为 48%、30%、50%、57%、7.5%、12% 、 和 58% ，分别。在 254 个可分型的分离株中，152 个是携带 stx1 或 stx2 基因或两者的 STEC。结论：通过不同器官的组织病理学检查，对不同致病型大肠杆菌进行体内比较，可将大肠杆菌致病型分为轻毒力、中毒力和高毒力菌株。统计分析显示不同血清群与毒力基因的存在之间存在显着相关性。