Study Highlights Genetic Diversity, Pathogen-Like Features in Non-Pathogenic E. Coli

In a paper appearing in Nature Communications, a University of Maryland School of Medicine team assesses genetic diversity in non-diarrheagenic Escherichia coli isolates found in fecal samples from almost 300 children under five-years old with or without diarrhea symptoms at sites in seven countries in sub-Saharan Africa and south Asia. With genome sequencing, multi-locus sequence typing, and phylogenetic analyses of 294 isolates collected through the Global Enteric Multicenter Study, the analysis points to extensive genetic diversity within the fecal E. coli samples considered, along with genomic resemblance to diarrheagenic forms of the bug. "Although these fecal E. coli lack the characteristic virulence factors of diarrheagenic E. coli pathotypes, many exhibit remarkable genomic similarity to previously described diarrheagenic isolates with differences attributed to mobile elements," the authors report, noting that the finding "raises an important question of whether these non-diarrheagenic fecal E. coli may have at one time possessed the mobile element-encoded virulence factors of diarrheagenic pathotypes or may have the potential to acquire these virulence factors."