Prevalence of Enterohaemorrhagic and Enteroaggregative E. coli among Children with Diarrhea in Najaf, Iraq

Document Type : Original Articles


1 Ministry of Education, General Directorate of Education in Al-Qadisiyah, Al-Qadisiyah, Iraq

2 Ministry of Education, General Directorate of Education in Najaf, Najaf, Iraq

3 Department of Biology, College of Education for Girls, University of Kufa, Kufa, Iraq


Diarrhea is one of the leading causes of morbidity and mortality among children under 5 years old in developing countries. The classification of diarrheagenic E. coli (DEC) strains among children with diarrhea is still receiving low attention. The present study aimed at determining the prevalence of enterohaemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC) among children under 5 years old suffering from acute diarrhea. Stool samples (n=100) were collected from children under 5 years old suffering from acute diarrhea for the molecular detection of EHEC (using stx1 and stx2) and EAEC (using aat) by polymerase chain reaction technique. The results showed a high percentage of isolation of EHEC from stool samples, in compression to EAEC; accordingly, among 75 identified DEC isolates, 15.9% belonged to EHEC, while 5.3% belonged to EAEC. Among EHEC, stx1 was highly prevalent among isolates (9.3%), in comparison to stx2 (6.6%). A high frequency of EHEC was detected in males in the age group of 7-12 months, whereas EAEC was found in females in the age group of 13-19 months. In conclusion, EHEC and EAEC were associated with bloody and watery diarrhea among children under 5 years old. Genes associated with virulence factors (i.e., stx1, stx2, and aat) could be used as genetic markers for the detection of EHAE and EAEC.


Main Subjects

  1. Yu J, Jing H, Lai S, Xu W, Li M, Wu J, et al. Etiology of diarrhea among children under the age five in China: Results from a five-year surveillance. J Infect. 2015;71(1):19-27.
  2. Scallan E, Hoekstra RM, Angulo FJ, Tauxe RV, Widdowson MA, Roy SL, et al. Foodborne illness acquired in the United States--major pathogens. Emerg Infect Dis. 2011;17(1):7-15.
  3. Thomas DE, Elliott EJ. Interventions for preventing diarrhea-associated hemolytic uremic syndrome: systematic review. BMC Public Health. 2013;13:799.
  4. Pereira AL, Ferraz LR, Silva RS, Giugliano LG. Enteroaggregative Escherichia coli virulence markers: positive association with distinct clinical characteristics and segregation into 3 enteropathogenic E. coli serogroups. J Infect Dis. 2007;195(3):366-74.
  5. Ferens WA, Hovde CJ. Escherichia coli O157:H7: animal reservoir and sources of human infection. Foodborne Pathog Dis. 2011;8(4):465-87.
  6. Faddin JFM. Biochemical Tests for Identification of Medical Bacteria: Lippincott Williams & Wilkins; 2000.
  1. Majowicz SE, Scallan E, Jones-Bitton A, Sargeant JM, Stapleton J, Angulo FJ, et al. Global incidence of human Shiga toxin-producing Escherichia coli infections and deaths: a systematic review and knowledge synthesis. Foodborne Pathog Dis. 2014;11(6):447-55.
  2. Ijaz S, Verbeek J, Seidler A, Lindbohm ML, Ojajarvi A, Orsini N, et al. Night-shift work and breast cancer--a systematic review and meta-analysis. Scand J Work Environ Health. 2013;39(5):431-47.
  3. Saxena T, Kaushik P, Krishna Mohan M. Prevalence of E. coli O157:H7 in water sources: an overview on associated diseases, outbreaks and detection methods. Diagn Microbiol Infect Dis. 2015;82(3):249-64.
  4. Bryan A, Youngster I, McAdam AJ. Shiga Toxin Producing Escherichia coli. Clin Lab Med. 2015;35(2):247-72.
  5. Keir LS. Shiga toxin associated hemolytic uremic syndrome. Hematol Oncol Clin North Am. 2015;29(3):525-39.
  6. Roussel C, Cordonnier C, Galia W, Le Goff O, Thevenot J, Chalancon S, et al. Increased EHEC survival and virulence gene expression indicate an enhanced pathogenicity upon simulated pediatric gastrointestinal conditions. Pediatr Res. 2016;80(5):734-43.
  7. Pabst WL, Altwegg M, Kind C, Mirjanic S, Hardegger D, Nadal D. Prevalence of enteroaggregative Escherichia coli among children with and without diarrhea in Switzerland. J Clin Microbiol. 2003;41(6):2289-93.
  8. Meza-Segura M, Zaidi MB, Vera-Ponce de Leon A, Moran-Garcia N, Martinez-Romero E, Nataro JP, et al. New Insights Into DAEC and EAEC Pathogenesis and Phylogeny. Front Cell Infect Microbiol. 2020;10:572951.
  9. Sambrook J, Fritsch EF, Maniatis T. Molecular Cloning: A Laboratory Manual: Cold Spring Harbor Laboratory; 1989.
  10. Savarino SJ, Fasano A, Robertson DC, Levine MM. Enteroaggregative Escherichia coli elaborate a heat-stable enterotoxin demonstrable in an in vitro rabbit intestinal model. J Clin Invest. 1991;87(4):1450-5.

17.          Alfinete NW, Bolukaoto JY, Heine L, Potgieter N, Barnard TG. Virulence and phylogenetic analysis of enteric pathogenic Escherichia coli isolated from children with diarrhoea in South Africa. Int J Infect Dis. 2022;114:226-32.