Genotypic and phenotypic features of enteropathogenic Escherichia coli isolated in industrialized and developing countries

Simona Santona,Piero Cappuccinelli,Moises Francisco,Mohsin Sidat,Paola Rappelli,Nicia Diaz,Pier Luigi Fiori

doi:10.3855/jidc.3054

Simona Santona, Piero Cappuccinelli + Show 5 more

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https://doi.org/10.3855/jidc.3054

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Abstract

Typical EPEC are considered a leading cause of diarrhoea in developing countries, while atypical EPEC have been isolated more frequently in developed areas. The actual geographic distribution of the two EPEC subgroups is controversial, since data can be highly influenced by laboratory resources. This study aimed to compare the distribution of typical and atypical EPEC among children in developed and developing countries, and to characterize the bacterial isolates, using a unique methodological approach. A total of 1,049 E. coli were isolated from faeces of children with acute diarrhoea in Mozambique, Angola and Italy, and processed by PCR to assess the presence of a large panel of virulence genes. All isolates classified as EPEC were further characterized by evaluating adherence and capability to induce actin rearrangement on Hep-2 cells. Overall we isolated 59 EPEC, likewise distributed in the three countries, representing the 5.04%, 4.44% and 6.97% of all Mozambican, Angolan and Italian isolates, respectively. Nevertheless, the geographic distribution of the two EPEC subgroups was not homogeneous: in Italy we isolated 28 aEPEC but no tEPEC, while in Angola and Mozambique the percentage of the two subgroups was comparable. Twelve atypical EPEC were FAS positive and able to induce localized-like adherence on Hep-2 cells, but no correlation with the geographic origin of isolates was observed. Atypical EPEC are present in sub-Saharan areas in a percentage similar to that of typical strains, and are not mainly restricted to industrialized countries, as it was previously supposed.

Highlights

Typical enteropathogenic E. coli (EPEC) are considered a leading cause of diarrhoea in developing countries, while atypical EPEC have been isolated more frequently in developed areas
We examined a total of 1,049 E. coli strains, which were isolated from children with diarrhoea in both developed (Italy) and developing countries (Mozambique and Angola)
ETEC strains, for instance, represent the 4.51% of all E. coli isolated in Mozambique and the 6.3% of Angolan isolates, but in Italy they have been isolated in only one patient

Summary

Introduction

Typical EPEC are considered a leading cause of diarrhoea in developing countries, while atypical EPEC have been isolated more frequently in developed areas. This study aimed to compare the distribution of typical and atypical EPEC among children in developed and developing countries, and to characterize the bacterial isolates, using a unique methodological approach. Enteropathogenic E. coli, which are the first to be recognized as a leading cause of infantile diarrhoea, do not produce toxins and are not invasive [2]. Their primary pathogenetic mechanism is a lesion called “Attaching and Effacing” (A/E), characterized by microvilli destruction [3]. It harbours several genes involved in pathogenicity, including eae, which codes for intimin, a bacterial outer membrane protein that mediates the intimate adhesion between bacteria and enterocytes [6]

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