Serotyping and prevalence of stx gene among E. coli isolates from HIV/AIDS patients with diarrhea; Shiraz, Iran

Abstract

Background/aimDiarrhea is significant morbidity in individuals with HIV which is caused by a multitude of etiologies such as infectious agents, malignancies, and medications. This complication may reduce the quality of life and increase the mortality rate in the advanced form of this disease. Among infectious reasons, bacterial species such as Escherichia coli (E. coli) are the main causes of diarrhea. Enterohemorrhagic Escherichia coli (EHEC) species with the potential of Shiga toxin-producing can be the main cause of severe diarrhea and life-threatening HIV patients. Stx genes as the main factor and causative agent of Shiga toxin-producing in E. coli isolates can be pointed to determine the prevalence of EHEC is a diarrheal causative agent in HIV patients. MethodologyThis cross-sectional study was conducted from June 2019 to June 2020, which comprised 117 HIV-positive patients with diarrhea. Collected stool samples were evaluated for diarrheal bacteria (such as Shigella, salmonella, and E. coli) by standard phenotypic, serology, and conventional molecular techniques. ResultsE. coli was detected in 110 samples. Based on the distribution of virulence genes,25 (22.72%) isolates belonged to the enteropathogenic E. coli (EPEC) group 40% and 60% of these isolates were confirmed as typical and atypical EPEC, Respectively. 21(19.00%) isolates belonged to the enterohemorrhagic E. coli (EHEC) group, 5 (4.54%) to Shiga toxin-producing E. coli (STEC). While, 6 (30.00%) isolates carried Stx1, 10 (50.00%) Stx2 and 4 (20.00%) harbored both stx1 and stx2. ConclusionRelatively high prevalence of Shiga toxigenic E. coli isolates in studied HIV patients shows a threat of infectious agents as a cause of diarrhea in immunocompromised patients who must be careful about infectious control disciplines.