Artículo de revista
Cumulative acquisition of pathogenicity islands has shaped virulence potential and contributed to the emergence of LEE-negative Shiga toxin-producing Escherichia coli strains
Fecha
2019Registro en:
Emerging Microbes and Infections, Volumen 8, Issue 1, 2019, Pages 486-502
22221751
10.1080/22221751.2019.1595985
Autor
Montero, David Arturo
Canto, Felipe del
Velasco, Juliana
Colello, Rocío
Padola, Nora Lia
Salazar, Juan Carlos
Martín, Carla San
Oñate, Ángel
Blanco, Jorge
Rasko, David A.
Contreras, Carmen
Puente, José Luis
Scheutz, Flemming
Franz, Eelco
Vidal Álvarez, Roberto
Institución
Resumen
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens causing severe gastroenteritis, which may lead to hemolytic uremic syndrome. The Locus of Enterocyte Effacement (LEE), a Pathogenicity Island (PAI), is a major determinant of intestinal epithelium attachment of a group of STEC strains; however, the virulence repertoire of STEC strains lacking LEE, has not been fully characterized. The incidence of LEE-negative STEC strains has increased in several countries, highlighting the relevance of their study. In order to gain insights into the basis for the emergence of LEE-negative STEC strains, we performed a large-scale genomic analysis of 367 strains isolated worldwide from humans, animals, food and the environment. We identified uncharacterized genomic islands, including two PAIs and one Integrative Conjugative Element. Additionally, the Locus of Adhesion and Autoaggregation (LAA) was the most prevalent PAI among LEE-negative strains and we found that it contributes to colonization of the mice intestine. Our comprehensive and rigorous comparative genomic and phylogenetic analyses suggest that the accumulative acquisition of PAIs has played an important, but currently unappreciated role, in the evolution of virulence in these strains. This study provides new knowledge on the pathogenicity of LEE-negative STEC strains and identifies molecular markers for their epidemiological surveillance.