Prevalence and virulence gene profiling of enteroaggregative Escherichia coli in malnourished and nourished Brazilian children

Diagn Microbiol Infect Dis. 2017 Oct;89(2):98-105. doi: 10.1016/j.diagmicrobio.2017.06.024. Epub 2017 Jul 4.

Abstract

The impact of enteroaggregative E. coli (EAEC) infection on childhood malnutrition and inflammation has been suggested, regardless of diarrhea. We investigated whether EAEC and its virulence-related genes (VRGs) are associated with malnutrition in a case-control study. Children aged 6-24 months from Brazil were enrolled as malnourished if weight-for-age Z-score (WAZ) ≤ -2 and nourished if WAZ > -1. Stools were cultured and examined for E. coli. DNA was extracted from fecal isolates and tested for EAEC by polymerase chain reaction (PCR). Positive samples were analyzed by 5 multiplex PCRs to identify 20 EAEC VRGs. Biomarkers of intestinal barrier function and inflammation were measured. The prevalence of EAEC was 39.94%. Samples that presented both aaiC and aatA genes were associated with malnutrition (P = 0.045). A high prevalence of VRGs was observed and the aafC gene was significantly associated with malnourished (P = 0.0101). Strains lacking aar and pic genes were associated with malnutrition (P = 0.018), while the concomitant presence of aar, pic, agg4A, and capU genes was associated with nourished (P = 0.031). These data reinforce the EAEC impact on malnutrition, the importance of aar as negative regulator and the great contribution of AAF/II fimbria for the pathobiology of EAEC.

Keywords: Enteroaggregative E. coli; Malnutrition; Virulence profile.

MeSH terms

  • Brazil / epidemiology
  • Case-Control Studies
  • Child, Preschool
  • Escherichia coli / genetics
  • Escherichia coli / isolation & purification
  • Escherichia coli / pathogenicity*
  • Escherichia coli Infections / epidemiology
  • Escherichia coli Proteins / genetics*
  • Female
  • Fimbriae, Bacterial / genetics*
  • Humans
  • Infant
  • Male
  • Malnutrition / microbiology*
  • Multiplex Polymerase Chain Reaction
  • Virulence / genetics
  • Virulence Factors / genetics*

Substances

  • Escherichia coli Proteins
  • Virulence Factors