Use of penicillin-binding proteins for the identification of enterococci

The results of 20 physiological and fermentation tests and examination of the penicillin-binding proteins (PBPs) of 85 enterococcal strains demonstrated that the genus Enterococcus could be divided into at least nine distinct species: E. faecalis, E. faecium, E. durans, E. hirae, E. avium, E. gallinarum, E. casseliflavus, E. malodoratus and E. mundtii. Each species had a specific pattern of at least five PBPs, with molecular masses in the range of about 40-130 kDa. The pattern of PBPs may be useful for identification purposes, since some strains with unusual fermentation characteristics were assigned to species by this technique.