Study of the growth and production of Yersinia enterocolitica biofilm in different meat juice concentrations.

LUCERO ESTRADA, CECILIA; IRIARTE, HEBE JORGELINA

Mendoza

Jornada; Reunión Conjunta SAIB-SAMIGE 2020.; 2020

Sociedades de Biología de la Republica Argentina

Yersinia enterocolitica (Ye) is the cause of bacterial yersiniosis and gastroenteritis. Transmission is through contaminated food or water. Pigs are the main reservoir, but it is also found in birds, aquatic animals, and even pets. Ye is classified into 6 biogroups and more than 57 serogroups. Pathogenicity is associated with virulence factors according to a specific serogroup/biogroup. The biofilm is a community of growing cells embedded in a matrix of polysaccharides, it forms on various surfaces, such as glass, metals and plastics, favoring cross contamination in food processing. The objective of this work was to use raw pork meat juice (MJ) as a model to study its effects on biofilm formation. Seventeen strains of Ye isolated previously in our laboratory were studied. For MJ extraction, a cut of minced lean pork was subjected to continuous freezing/thawing for several days and the released juice was collected. It was centrifuged at 10,000 rpm/10min, pre-filtered on a 0.45 μm membrane, sterilized with a 0.2 μm membrane and stored at -80°C. The strains were seeded onto Mac Conkey agar (MC) and incubated for 48h/25°C. Finally, they were seeded in trypticase soy broth (TSB) and incubated for 24h/25°C. The strains were inoculated at different concentrations of MJ (0%, 25%, 50%, 75% and 100%) with TSB plus 0.25% glucose (TSBG) and the respective dilution controls, on a polystyrene U-bottom plate, culturing at 25°C/24 h. The count was made following the microdroplet technique (in triplicate). To determine the biofilm formation, the crystal violet staining technique was performed. The medium that favored the formation of biofilm was 50% MJ/TSBG, 14 of the 17 strains formed a stronger biofilm with respect to the TSBG medium. So, MJ particles on abiotic surfaces facilitated biofilm formation. These results suggested that MJ residues on inert surfaces favor initial adhesion and biofilm formation of Ye. At a MJ concentration greater than 50%, there was a decrease in biofilm formation. Possibly at high concentration, the MJ nutrients sediment forming an adherent layer that covers the surface, causing the biofilm to adhere above it and detach along with it in the washes.