Frequency of fiveEscherichia Colipathotypes in Iranian adults and children with acute diarrhea

Abstract

20Background: knowledge about the distribution of Escherichia Coli (E. coli) pathotypes in Iran is 21 limited to studies with small scale and limited scope. This nation-wide survey aims to provide a 22 more generalizable estimate of pathogenic E. coli distribution in Iran. 23 acute diarrhea cases of 15 provinces. Culture-positive E. coli samples were tested with PCR for 25 detection of five E. coli pathotypes (STEC, ETEC, EPEC, EAEC, and EIEC). Frequency of these 26 pathotypes was estimated for different provinces, age groups, and months/seasons. 27Results: Of 1305 diarrheal samples, 979 were E. coli-positive (prevalence: 75.0%; 95% CI: 72.6, 28 77.3%). Pathogenic E. coli was detected in 659 diarrheal samples (prevalence: 50.5%; 95% CI: 29 47.8, 53.2%). STEC and EIEC was the most and the least frequent pathotypes (35.4% and 0.3%, 30 respectively). ETEC (14.0%) and EPEC (13.1%) were the second and the third frequent 31 pathotypes, respectively. EAEC was not highly prevalent (4.3%). Fars and Razavi Khorasan 32 provinces had the highest and lowest frequencies (88.7% and 34.8%, respectively). E. coli 33 pathotypes were more frequent in warmer (i.e., spring and summer) than cooler (i.e., fall and 34 winter) seasons. The highest frequency of pathogenic E. coli was observed in infants and 35 children under 5 years (73% each). There was no association between sex and pathogenic E. coli 36 infection. 37 Conclusions: Diarrheagenic E. coli may be an important cause of acute diarrhea in adults and 38 children in Iran. STEC and ETEC seem to be widespread and show a peak in warmer seasons. 39 This finding could impact the recommended use of STEC and ETEC vaccines during warmer 3 40 seasons, especially for infants, young children and elderlies. Monitoring the rate of 41 diarrheagenic E. coli infection, E. coli serotypes, and their antibiotic resistance is recommended 42 for evaluations of time-trends and effectiveness of interventions. 43 Author summary 46 Escherichia coli, also known as E. coli is a bacterium of the genus Escherichia that is normally 47 found in the lower intestine of human. Most E. coli strains are harmless, but some can cause 48 infection in the gastrointestinal tract, causing diarrhea. These pathogenic E. coli strains are 49 classified based on their mechanism of pathogenesis. In this regard, five important E. coli 50 strains include Shiga toxin-producing E. coli (STEC), enterotoxigenic E. coli (ETEC), 51 enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), and enteroinvasive E. coli 52 (EIEC). In a national survey conducted in Jan 2013 till Jan 2014, we collected 1305 diarrheal 53 samples from 15 (out of 31) provinces of Iran. Of these, 979 samples (75%) were E. coli-positive 54in the culture test. Molecular tests showed that 659 samples were pathogenic E. coli, 55 suggesting that 50.5% of the diarrhea cases were induced due to pathogenic E. coli infection. 56 The most prevalent pathogenic E. coli strains in Iran were STEC (35.4%) and ETEC (0.3%), and 57 were more commonly detected in warm...

Detection of Some Virulence Genes in Diarrheagenic Escherichia Coli Pathotypes in Children Under Five Years in Aleppo City

“…Our results are consistent with a study conducted in Brazil, which reported a prevalence of 4.4% [30]. Similarly, Iranian studies have reported prevalence rates of 3.1% and 1.8%, respectively [25][26][27][28][29][30][31][32] . whereas it is far a little bit with a study in Colombia, South America 0.29% 34 whereas with the results of CostRica study 19.23%.…”