Enterococcus gallinarum and E. casseliflavus are difficult to differentiate from other enterococci, particularly E.faecium. The former two species were found to produce acid from methyl-alpha-D-glucopyranoside in phenol red broth, while E.faecalis strains and strains of the E.faecium species group, including E.faecium, E.durans, E. hirae, and E.mundtii, failed to produce acid from this substrate.