CONICET | Buscador de Institutos y Recursos Humanos

Yersinia enterocolitica (Ye) is an important Gram-negative pathogen that is transmitted mainly through contaminated water and food. This bacterium species is classified in 6 biotypes (B) and in more than 57 serotypes (O). Five of the six biotypes (1B and 2 -5) are considered pathogens to human being due to the presence of a virulence plasmid pYV and several chromosomal virulence genes; these strains are confined to the gastrointestinal tract causing enteritis or diarrhea. The biofilm lifestyle of growth confers a protective advantage to bacteria, which is physiologically distinct from the planktonic counterpart of the same species, becoming more resistant to the host defense and adverseenvironmental conditions. Ye is able to synthesized two N-acil-homoserin lactones (AHSLs) or autoinducers. Biofilm formation, virulence and antibiotic resistance expression are influenced by Quorum sensing via the autoinducers. The aim of this work was to study the ability to form biofilm of two different Ye bioserotypes strains. Y. enterocolitica CLC001 B1A/O:7,8-8-8,2 is a deficient in pYV(pYV-) strain and was isolated from food, while Y. enterocolitica WAP B1B/O:8, is a reference strain that carries the virulence plasmid (pYV+) and was isolated from human feces. Biofilm formation on abiotic surfaces was assayed by the crystal violet technique using 96 wells polystyrene (PE) plates orglass tubes. Strains were incubated in TSB medium added with 0.25% glucose at 24°C. At different times, the planktonic and sessile growths were measured at OD 655 nm and 550 nm, respectively. After 24 h, Ye CLC001 strain developed stronger biofilms both on PE and glass surfaces in comparison with WAP strain (3.13 ± 0.27 vs 2.03 ± 0.21 (p