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

Objective To study the significance of enteroaggregative Escherichia coli (EAEC) as a pathogen causing acute diarrhea and a commensal in healthy nourished and malnourished children younger 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 diarrhea (n = 110). E coli isolates were confirmed as EAEC by pCVD432 polymerase chain reaction. Multiplex polymerase chain reactions were used to identify 22 virulence-related genes and phylogeny. Antibiotic susceptibility, adherence, and biofilm-forming potential also were studied. Results Overall, 16.6% of children were malnourished. EAEC detection was greater among children with acute diarrhea (16%) than nourished (6%) and malnourished nondiarrheal controls (2.7%). We found an association of EAEC infections with age <2 years (P =.0001) in the diarrheal group. Adhesive variants adhesion fimbriae IV and adhesion fimbriae 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 =.0003). A high degree of multidrug resistance 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. Conclusions 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.

Automated summary

The study aimed to investigate the role of enteroaggregative Escherichia coli (EAEC) in childhood diarrhea and as a commensal in children younger than five years old. EAEC detection was higher in children with acute diarrhea compared to nourished and malnourished controls. Adhesive variants like adhesion fimbriae IV and II were significantly associated with diarrhea, and aggR and aar genes showed associations with disease severity. High rates of multidrug resistance were observed in the diarrheal group. Phylogenetic analysis revealed differences in EAEC strains between diarrheal and non-diarrheal groups.