IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Study of the capability to form biofilms of two Yersinia enterocolitica strains from different bioserotypes
Autor/es:
DI MARCO N.; RUSSO D.M.; ZORREGUIETA A.; PUNGITORE C. AND LUCERO ESTRADA C.
Lugar:
Córdoba
Reunión:
Congreso; XI Congreso Argentino de Microbiología General. Asociación Civil de Microbiología General -SAMIGE 2015.; 2015
Institución organizadora:
Asociación Civil de Microbiología General
Resumen:
Yersinia enterocolitica (Ye) is an important Gram-negative pathogen that is transmitted mainly through contaminated water and food. This species are 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 adverse environmental conditions.Ye is able to synthesized two N-acil-homoserinlactones (AHSLs) or autoinducers. Biofilm formation, virulence and antibiotic resistance expression are influenced by Quórum 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:7,8-8-8,2is 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 or glass 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<0.01) on PE and  1.96 ± 0.21 vs 1.31 ± 0.18(p<0.05) on glass surfaces respectively). Then, the ability to produce lactones was quantified with the biosensor Chromobacterium violaceum which synthesizes violacein in presence of exogenous autoinducers.Co- cultures were performed in TSB for 24 h at 25ºC in shaking conditions.  After the incubation period, the amount of released violacein was quantified at OD 585 nm. No differences in Ye AHSLs production were observed between both strains. Furthermore, the biofilm developed after 24h on a glass surface was observed by Laser Scanning Confocal Microscopy (LSCM). Briefly, Ye biofilms were fixed with paraformaldehyde and stained using propidium iodide. Both Ye strains were able to firmly attach to the glass chambered slide,stablishing bacterial aggregates or microcolonies. Our results suggest that both pathogenic and non pathogenic Y.enterocolitica strains have the capacity to form biofilm onto different abiotic surfaces. Thus it could be considered as an alternative virulence trait.