Prevalence of common diarrheagenic enterobacteriaceae in Iran (2000-2023): a systematic review and meta-analysis

Bacterial gastroenteritis is a significant public health concern, capable of causing severe infections. Among the various pathogens involved, those belonging to the Enterobacteriaceae family are the most frequently isolated and associated with gastrointestinal disorders. This study aimed to investigate the prevalence of common diarrheagenic Enterobacteriaceae in Iran over the past two decades, from 2000 to 2023.

A comprehensive systematic search was conducted across multiple databases, including EMBASE, HINARI, MEDLINE, PubMed, Google Scholar, and the Cochrane Library. The focus was on observational published studies reporting the prevalence of diarrheagenic Enterobacteriaceae in Iran during 2000 and 2023. The criteria did not restrict patient demographics such as age, gender, health conditions, or occupation. This meta-analysis employed a 95% confidence interval (CI) for analysis. Evidence of heterogeneity was determined using an I² value greater than 50%. To explore potential sources of heterogeneity, subgroup analysis and meta-regression analysis were performed. Statistical analyses were executed using R version 4.3.2 along with the meta package. A p-value less than 0.05 was considered statistically significant.

Out of 3,701 papers reviewed, 56 studies met the inclusion criteria and were analyzed. The overall pooled prevalence of diarrheagenic Enterobacteriaceae species from 2000 to 2023 was 14.0% (95% CI: 0.11-0.17). Subgroup analysis revealed Shigella spp. had the highest prevalence at 18.0% (95% CI: 0.13-0.24; I²=99%), followed by diarrheagenic Escherichia coli at 11.0% (95% CI: 0.09-0.15; I²=97%), Salmonella spp. at 9.0% (95% CI: 0.05-0.17; I²=99%), and Yersinia spp. at 2.0% (95% CI: 0.00-0.10; I²=94%). Prevalence trends showed Shigella spp. increasing from 4% (95% CI: 0.03-0.08) in 2000-2004 to 36% (95% CI: 0.20-0.55) in 2021-2023. Diarrheagenic E. coli (DEC) showed no clear pattern, ranging from 5% (95% CI: 0.01-0.24) to 17% (95% CI: 0.07-0.36). Salmonella spp. exhibited more significant fluctuations, rising from 6% (95% CI) in both 2000-2004 and 2005-2008 periods to 20% (95% CI: 0.03-0.66) in 2009-2012 and 30% (95% CI: 0.11-0.60) in 2017-2020. Yersinia spp. was only determined in 2000-2004 with a pool prevalence of 12% (95% CI: 0.00-0.91). Sub-species analysis revealed Shigella sonnei was the most prevalent species among Shigella spp. in Iran, accounting for 42% of cases (95% CI: 0.33-0.52). Regarding DEC species, Enteroaggregative E. coli (EAEC) and Enterotpathogenic E. coli (EPEC) had the highest rate at 15% (95% CI). Furthermore, a pool prevalence of 2% (95% CI: 0.00-0.89) was reported for Yersinia enterocolitica among diarrheagenic Enterobacteriaceae in Iran.

This meta-analysis provides valuable insights into the prevalence of diarrheagenic Enterobacteriaceae in Iran over the past two decades. The findings highlight the significant impact of these pathogens on public health, with Shigella spp. showing the highest prevalence and increasing trends. Further research should investigate the factors contributing to the prevalence of diarrheagenic Enterobacteriaceae, including genetic diversity of diarrheagenic Enterobacteriaceae isolates, molecular mechanisms underlying the virulence of these pathogens, or antibiotic resistance patterns.