Reservoirs of infection with Shiga toxin-producing Escherichia coli in Iran: Systematic review

Introduction: Shiga toxin-producing Escherichia coli (STEC) infection, an important cause of hemorrhagic colitis and hemolytic uremic syndrome, is associated with high mortality and morbidity. The chief sources of STEC are contaminated food and drinking water. Aim: This study aimed to identify relevant sources of STEC transmission in Iran. Methods: Search engines of PubMed, EMBASE, OVID, SCOPUS, Web of Sciences, Google Scholar, and Iranian databases of health.barakatkns.com, IranMedex, MagIran, SID, dociran, PDFiran, and ganj.irandoc were used to review studies published about food and animal sources of STEC in Iran between 1985 and 2018. Quality and risk of bias were assessed to estimate point prevalence and proportions, which are reported with their 95% confidence intervals (CIs). Results: A total of 58 articles describing 17480 specimens were eligible for inclusion in the final analysis. Most studies, except two case control studies, had a cross-sectional design. While 39 studies had good quality, the remainder had poor quality with low to moderate risk of bias. Of 6779 samples positive for E. coli, 1587 were positive for STEC; the pooled prevalence of STEC was 5.7% (95% CI, 3.4–8.6) in food studies and 10.2% (95% CI, 7.0–13.9) in animal studies. Conclusion: A significant proportion of food and animal samples in Iran are contaminated with STEC. Registration Number: PROSPERO 2016: CRD42016033019.