Enterococci are Gram-positive facultative anaerobes inhabiting the gastrointestinal tract, the oral cavity, and the vagina in humans as normal commensals. E. faecalis and E. faecium are the species most commonly associated with colonization of the human gastrointestinal tract.
E. cecorum (EC) is a species of bacteria that is normally found in the gastrointestinal tract of healthy adult chickens. However, an emerging pathogenic strain of EC has emerged that has been associated with outbreaks of Enterococcal-associated vertebral osteoarthritis (EVOA) in broiler chickens and breeders.
In 2012, two flocks in North Carolina developed enterococcal spondylitis (ES). The affected birds developed paresis and paralysis and were unable to stand or walk.