Enterococcus faecium, a Gram-positive bacterium in the genus Enterococcus,

1. Pathogenic Properties:

   • Antibiotic Resistance: E. faecium has developed multi-drug antibiotic resistance.

   • Virulence Factors: It uses colonization and secreted factors for virulence, including enzymes that break down fibrin, protein, and carbohydrates.

   • Biofilm Formation: The enterococcal surface protein (Esp) allows it to aggregate and form biofilms.

   • Combatting Pathogens: By producing enterocins A, B, and P (genus-specific bacteriocins), it combats pathogenic gut microbes like Escherichia coli.

2. Probiotic Use:

   • E. faecium Strain NCIMB 10415 is used as a probiotic in animal feed as an alternative to antibiotics.

   • However, constant exposure to high levels of this microbe can result in immunosuppression, predisposing livestock to severe Salmonella infections.