Allelic variations of intimin virulence gene (eae) in typical and atypical enteropathogenic Escherichia coli isolated from children with and without diarrhea in a rural area of southern Mozambique

Enteropathogenic Escherichia coli (EPEC) is among the major causes of childhood diarrhea in low- and middle-income countries. The pathogenicity of EPEC strains has been associated with the expression of diverse virulence genes, therefore, it is possible that different EPEC isolates possess different pathogenic potentialities. However, there are limited data about the allelic distribution of EPEC critical virulence genes, especially in African settings. Herein, we assessed the molecular variability of the intimin virulence gene (eae) in EPEC isolates, recovered from children under 5 years in a case-control study of diarrheal disease in Manhiça, southern Mozambique, from 2007 to 2010. A total number of 157 EPEC isolates (53 cases of diarrhea and 104 controls) were characterized. The identification of EPEC and typing of its virulence genes was accomplished by conventional PCR. We compared the different intimin alleles within cases and controls, and clinically characterized the cases. Typical EPEC (eae with bfpA) was the most predominant with 71.9% (113/157), while atypical EPEC (eae only) was detected in 26.1% (41/157). Eighteen different intimin types were identified, with eae-λ (28.0%) the most frequently detected, followed by eae-β1 (24.8%) and eae-ξR/β2B‡§ (19.7%), although there were no statistically significant differences between cases and controls, suggesting a possible role of other virulence factors. When analyzing the potential implication of the intimin alleles with clinical characteristics, we found that eae-λ and eae-β1 were mostly detected in children with fever and vomiting, additional investigations are warranted. Our findings indicate a high diversity of intimin alleles among EPEC diarrheal isolates from a rural area in southern Mozambique. This is the first report on the molecular diversity of the EPEC intimin gene in Mozambique.