title: Analysis of the virulence of an atypical enteropathogenic Escherichia coli strain in vitro and in vivo and the influence of type three secretion system.
abstract: Atypical enteropathogenic Escherichia coli (aEPEC) inject various effectors into intestinal cells through a type three secretion system (T3SS), causing attaching and effacing (A/E) lesions. We investigated the role of T3SS in the ability of the aEPEC 1711-4 strain to interact with enterocytes in vitro (Caco-2 cells) and in vivo (rabbit ileal loops) and to translocate the rat intestinal mucosa in vivo. A T3SS isogenic mutant strain was constructed, which showed marked reduction in the ability to associate and invade but not to persist inside Caco-2 cells. After rabbit infection, only aEPEC 1711-4 was detected inside enterocytes at 8 and 24 hours pointing to a T3SS-dependent invasive potential in vivo. In contrast to aEPEC 1711-4, the T3SS-deficient strain no longer produced A/E lesions or induced macrophage infiltration. We also demonstrated that the ability of aEPEC 1711-4 to translocate through mesenteric lymph nodes to spleen and liver in a rat model depends on a functional T3SS, since a decreased number of T3SS mutant bacteria were recovered from extraintestinal sites. These findings indicate that the full virulence potential of aEPEC 1711-4 depends on a functional T3SS, which contributes to efficient adhesion/invasion in vitro and in vivo and to bacterial translocation to extraintestinal sites.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil.
authors.forename: Suely C F
authors.initials: SC
authors.lastname: Sampaio
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil.
authors.forename: Fabiana C
authors.initials: FC
authors.lastname: Moreira
authors.affiliation: Departamento de Cirurgia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Pedro de Toledo 781, 9th floor, Vila Clementino, 04039-032 São Paulo, SP, Brazil.
authors.forename: Ana M A
authors.initials: AM
authors.lastname: Liberatore
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil.
authors.forename: Mônica A M
authors.initials: MA
authors.lastname: Vieira
authors.affiliation: Departamento de Ornitopatologia, Faculdade de Medicina Veterinária, Universidade de São Paulo, Avenida Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, 05508-900 São Paulo, SP, Brazil.
authors.forename: Terezinha
authors.initials: T
authors.lastname: Knobl
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil.
authors.forename: Fabiano T
authors.initials: FT
authors.lastname: Romão
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil ; Departamento de Microbiologia e Imunologia, Instituto de Biociências, UNESP, Distrito de Rubião Junior s/n, Botucatu, 18618-970 São Paulo, SP, Brazil.
authors.forename: Rodrigo T
authors.initials: RT
authors.lastname: Hernandes
authors.affiliation: Departamento de Ornitopatologia, Faculdade de Medicina Veterinária, Universidade de São Paulo, Avenida Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, 05508-900 São Paulo, SP, Brazil.
authors.forename: Claudete S A
authors.initials: CS
authors.lastname: Ferreira
authors.affiliation: Departamento de Ornitopatologia, Faculdade de Medicina Veterinária, Universidade de São Paulo, Avenida Prof. Dr. Orlando Marques de Paiva 87, Cidade Universitária, 05508-900 São Paulo, SP, Brazil.
authors.forename: Antônio P
authors.initials: AP
authors.lastname: Ferreira
authors.affiliation: Fleury Medicina e Saúde, Avenida General Valdomiro de Lima 508, 04344-903 São Paulo, SP, Brazil.
authors.forename: Aloísio
authors.initials: A
authors.lastname: Felipe-Silva
authors.affiliation: Centro de Microscopia Eletrônica, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 1 st floor, 04023-062 São Paulo, SP, Brazil.
authors.forename: Rita
authors.initials: R
authors.lastname: Sinigaglia-Coimbra
authors.affiliation: Departamento de Cirurgia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Pedro de Toledo 781, 9th floor, Vila Clementino, 04039-032 São Paulo, SP, Brazil.
authors.forename: Ivan H J
authors.initials: IH
authors.lastname: Koh
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3rd floor, Vila Clementino, 04023-062 São Paulo, SP, Brazil.
authors.forename: Tania A T
authors.initials: TA
authors.lastname: Gomes
mesh_terms: D000818:Animals; D058947:Bacterial Secretion Systems; D018938:Caco-2 Cells; D004195:Disease Models, Animal; D020895:Enterocytes / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D054308:Enteropathogenic Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D009154:Mutation; D011817:Rabbits; D051381:Rats; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D058947:Bacterial Secretion Systems; D037521:Virulence Factors