Resumo

BUSTOS, C.P.; MARFIL, M.J.; LANZA, N.S.  e  GUIDA, N.. Estudio de la capacidad productora de biofilm en Streptococcus equi subsp. equi. Rev. vet. [online]. 2017, vol.28, n.1, pp.3-8. ISSN 1669-6840.

After attached, bacteria can grow in biofilms as a community of cells surrounded by an extracellular matrix synthesized by themselves. Streptococcus equi subsp. equi (S. equi) is a microorganism that produces strangles in horses. It can remain in nasopharynx and guttural pouches of recovered animals, situation that plays an important role in the dissemination of the infection. Some researchers have proposed the production of bacterial biofilm as a model of chronical infection and asymptomatic carriers in animals and human beings. The aim of this work was evaluate the capacity of biofilm production of S. equi. Eightyfour isolates of S. equi were studied by colorimetric and glass slides methods showing the presence of extracellular polysaccharide (PSE) and cell agglomerates. Values were obtained by a colorimetric method at 18 h of in-cubation and no difference was found with different culture media (p>0.05). The biggest production of biofilm was obtained at 36 h of incubation with highest values in the presence of equine plasma (p<0.05). Sixtysix percent of isolates showed PSE and no difference was observed between isolates of carriers and sick animals. There was a significant correlation between agglomerate and PSE formation (p<0.05). This is the first report of the capacity of biofilm production of S. equi and the presence of a substance compatible with extracellular polysaccharide which may favor the persistence of bacteria in carrier horses. Furthermore, some plasmatic component may be facilitating the formation of biofilm as it was previously observed for Streptococcus zooepidemicus. Further assays are needed to study this virulence factor to understand the behavior of S. equi in carrier horses.

Palavras-chave : equine; Streptococcus equi subsp. equi; biofilm; bacterial resistance.

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