Prevalence, acquired antibiotic resistance and bacteriocin production of Enterococcus spp. isolated from tunisian fermented food products

• A high incidence of E. spp. was recovered from Tunisian fermented foods.
• E. faecium and E. faecalis were the two most abundant species followed by E. casseliflavus, E. durans and E. mundtii.
• None of the enterococcal isolates showed acquired resistance to clinically relevant antibiotics, neither haemolytic activity.
• High percentage of the enterococcal isolates exhibited antilisterial bacteriocins activities.

In this study, a total of 100 fermented food products including dairy (Lben, Rayeb, Rigouta, and Jben) olive and vegetable products, harvested in Northwestern Tunisia, were investigated for the presence of Enterococcus spp. Our results showed high levels of contamination with Enterococcus spp., identified according to standard bacteriological, biochemical and phenotypic criteria. 143 isolates were recovered; E. faecium (46.15%) was the predominant species, followed by E. faecalis (27.27%), E. casseliflavus (12.58%), E. durans (8.39%) and E. mundtii (5.59%). None of the isolates showed acquired resistance againts clinically relevant drugs used for enterococcal infections treatment in human medicins, and no haemolytic activity was demonstrated. Furthermore, over 50% of the isolates within each species exhibited antilisterial bacteriocin production. Further data are needed to enhance understanding of bacteriocin production of enterococci in fermented food products as well as the potential risks to quality and safety, including possible transmission of antibiotic resistant organisms to human consumers.