Enterococcus spp.: Is It a Bad Choice for a Good Use-A Conundrum to Solve?

Area of Science:

• Microbiology
• Food Science
• Probiotics

Background:

• Lactic acid bacteria (LAB) of the genus *Enterococcus* are common in the gut flora and historically used as probiotics.
• However, their use is limited by the presence of virulence factors and antimicrobial resistance genes.
• This genus lacks Generally Recognized as Safe (GRAS) status or Qualified Presumption of Safety (QPS) listing.

Purpose of the Study:

• To review the limitations and hurdles hindering the use of *Enterococcus* spp. as probiotics.
• To discuss the future prospects and regulatory landscape for enterococci in food applications.

Main Methods:

• Literature review of studies on *Enterococcus* virulence factors and antibiotic resistance.
• Analysis of genetic structures and pathogenicity of foodborne versus clinical enterococcal isolates.
• Examination of regulatory aspects and risk assessment strategies for probiotic use.

Main Results:

• Enterococcal virulence factors are often strain-specific, with food isolates generally possessing fewer determinants than clinical ones.
• Food isolates are typically susceptible to clinically relevant antibiotics, indicating lower pathogenicity.
• Limited knowledge exists regarding the virulence factors and genetic makeup of foodborne enterococcal strains.

Conclusions:

• Strains intended for probiotic use in food must be free of virulence genes and susceptible to antibiotics.
• A thorough risk-benefit analysis, strain innocuity assessment, and adherence to regulations are essential for acceptance.
• Despite challenges, *Enterococcus* spp. can be valuable probiotics with appropriate evaluation and selection.