Enterococci in food: Risks and phage-based control strategies

Enterococci have become opportunistic pathogens and are deemed important hospital-acquired pathogens. Enterococci , especially Enterococcus faecalis and E. faecium , can cause various life-threatening infections, including urinary tract infections, bacteremia, nosocomial infections, and endocarditis. The widespread distribution of enterococci in various environments, including soil, water, and the gastrointestinal tracts of humans and animals, increases the likelihood of contaminating food products during different stages of production, processing, and handling. They become resistant to most antibiotic groups, including glycopeptides. Enterococci are used as probiotics in some countries and help in the ripening of some foods, like cheese. The extensive use of antibiotics in human treatments or livestock not only increases antibiotic resistance genes (ARGs) but also promotes the spread and transfer of ARGs among microorganisms. The spreading of vancomycin-resistant enterococci (VRE) is regarded as the most serious threat among acquired antibiotic resistance, and the spreading of VRE genes between animals and humans is possible. Bacteriophages are promising, effective antibacterial agents that can eliminate harmful bacteria without affecting the beneficial microbiota. Phage-derived endolysins can be used as a food preservative to control the growth of pathogens and extend the food shelf life. Several phages have been characterized against clinical enterococci, and recently, the use of phages and their endolysins against enterococci in food has emerged due to the possible threat of enterococci as a food-borne bacteria. Although there is a growing number of articles related to the treatment of infection, especially for E. faecium and E. faecalis , using phage and endolysin, the number of works focused on food is less abundant. In this review, we aimed to show the risk of enterococci in food and the role of phages and their endolysins in controlling enterococcal growth and ensuring food safety. • Enterococci probiotics may spread antimicrobial resistance and virulence genes. • Vancomycin-resistant enterococci can spread via livestock and food to humans. • Phages act as biocontrol agents to prevent and eliminate foodborne pathogens. • Endolysins are enzymes derived from phages and considered promising natural food biopreservatives.