Distinct Interaction of Two Atypical Enteropathogenic Escherichia coli Strains with Enterocytes In Vitro
Suely C. F Sampaio1, João R. C Andrade2, Jorge L. M Sampaio3, Célia R. W Carneiro1, Edna Freymüller4, Tânia A. T Gomes1, *
1 Departamento de Microbiologia, Imunologia e Parasitologia - Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3º andar – 04023-062- São Paulo, Brazil
2 Departamento de Microbiologia e Imunologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87 fundos 3° andar, 20551-030 - Rio de Janeiro, RJ, Brazil
3 Faculdade de Ciências Farmacêuticas – Universidade de São Paulo – Avenida Prof. Lineu Prestes, 580 – Bl 17 – São Paulo – 05508-900 – Brazil
4 Centro de Microscopia Eletrônica – Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 1º andar – 04023-062- São Paulo, Brazil
Typical and atypical Enteropathogenic Escherichia coli (EPEC) promote attaching-effacing lesions in intestinal cells but only typical EPEC carry the EPEC adherence factor plasmid. Atypical EPEC (aEPEC) are emerging agents of acute and persistent diarrhea worldwide. We aimed at comparing the ability of two aEPEC strains, 1711-4 (serotype O51:H40) and 3991-1 (serotype O non-typeable:non-motile) to invade, persist inside Caco-2 and T84 cells, and to induce IL-8 production. Typical EPEC strain E2348/69 was used for comparisons. The strains associated more significantly with T84 than with Caco-2 cells, with 3991-1 being the most adherent (P < 0.001). In contrast, aEPEC 1711-4 was significantly more invasive than the other strains in both cell lines, and was found within vacuoles near the basolateral cell surfaces. Strains persisted within both cell lines for at least 48 hours, but the persistence index was higher for 3991-1 in Caco-2 cells. IL-8 production was significantly higher from Caco-2 cells infected with 1711-4 for at least 48 hours (P < 0.001), and from T84 cells after 24 and 48 h than with the other strains (P = 0.001). We demonstrated that aEPEC are heterogeneous in various aspects of their interaction with enterocytes in vitro.
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* Address correspondence to this author at the Universidade Federal de São Paulo, Rua Botucatu 862, 3º andar – 04023-062- São Paulo, Brazil; Tel: 55 11 5083.2980; Fax: 55 11 5572 4711; E-mail: email@example.com