Prevalence, Virulence Gene Profiling and Characterization of Enteroaggregative Escherichia coli From Acute Diarrhea, Asymptomatic Nourished and Malnourished Children Less Than 5 Years of Age in India

J Pediatr. 2021 Mar 10;S0022-3476(21)00222-5. doi: 10.1016/j.jpeds.2021.03.010. Online ahead of print.

Abstract

Objective: To study the significance of EAEC as a pathogen causing acute diarrhea and a commensal in healthy nourished and malnourished children less than five years of age in the Chandigarh region and to address possible traits of EAEC virulence genes, biofilm formation, phylogroups and antibiotic resistance that would be correlated with diarrhea or carriage.

Study design: Stool samples were obtained from children with acute diarrhea (n=548), as well as nourished (n=550), and malnourished controls without diaarhea (n=110) . E. coli isolates were confirmed as EAEC by pCVD432 PCR. M-PCRs were used to identify 22 VRGs and phylogeny. Antibiotic susceptibility, adherence, and biofilm-forming potential were also studied.

Results: Overall, 16.6% of children were malnourished. EAEC detection was higher among acute diarrheal children (16%) than nourished (6%) and malnourished non-diarrheal controls (2.7%). We found an association of EAEC infections with age<2 years (p=0.0001) in the diarrheal group. Adhesive variants AAF/IV and AAF/II were significantly associated with diarrhea. The aggR and aar genes showed a positive and negative association with the severity of disease (P = .0004 and p=0.0003). A high degree of MDR was found (73.8%) in the diarrheal group. Most EAEC strains from the diarrheal group belonged to B2 and D phylogroups, whereas strains from non-diarrheal groups, which belonged to phylogroup B1.

Conclusion: EAEC is a significant contributor to childhood diarrhea, its presence as a commensal, and the significance of the association of various virulence factors among the EAEC isolated from diarrheal and non-diarrheal stools. These data reinforce the importance of aggR and aar as positive and negative regulators and the contribution of AAF/II and AAF/IV fimbria for the pathobiology of EAEC.

Keywords: Enteroaggregative Escherichia coli; Malnutrition; Multiplex PCR; Phylogeny; Virulence genes.