Biofilm formation, siderophore production, virulence-associated genes and genetic diversity of Yersinia enterocolitica from food

Résumé 0

Yersinia enterocolitica is widely found in nature and foods including those implicated in foodborne infections. The ability of this organism to multiply at refrigeration temperatures in food products with a prolonged shelf-life renders it a potential health risk for consumers. Y. enterocolitica isolates from food were investigated for biofilm formation and siderophore production at different temperatures (12, 25 and 37 °C) using the microtiter plate and CAS agar plate methods, respectively. The isolates were also evaluated with PCR for the presence of virulence genes and rep-PCR for genetic diversity. Most of the isolates showed high capability to form biofilm at all temperatures after 24 and 48 h of incubation. The results at 12 and 25 °C (P < 0.05) as well as at 25 and 37 °C (P < 0.05) showed a statistically significant difference in quantification of biofilm formation after 24 h; however, no difference was observed between findings at 12 and 37 °C (P > 0.05). There was a significant difference at 12 and 37 °C (P < 0.05) as well as at 25 and 37 °C (P < 0.05) after 48 h of incubation; conversely, no significant difference was observed between 12 and 25 °C (P > 0.05). Strong biofilm-producing isolates at 12 °C were found to be more after 48 h than after 24 h of incubation. Siderophore production was observed in 83.3% and 100% of the isolates at 25 and 37 ºC, respectively. However, no isolate produced siderophores at 12 °C. Genes myfA, fepA, fepD, fes, hreP, tccC and ymoA were detected in 16.7%, 33.3%, 100%, 100%, 44.4%, 5.6%, and 33.3% of the isolates, respectively. The rep-PCR revealed a high level of genetic differentiation among the isolates. The results indicated that Y. enterocolitica from food may act as a potential pathogen producing biofilm and siderophore while carrying virulence-associated genes.