Occurrence of Enterococcus spp. in waters

We studied 630 bacterial strains isolated from surface waters and determined as enterococci on the basis of their growth on Slanetz-Bartley agar in typical colonies. The strains were tested and characterized by several key conventional tests for basic differentiation of enterococci and by commercial test kits. We identified 135 strains of E. foecium (21 %), 115 E. foecalis (18 %), 30 E. mundtii (5 %), 27 E. hirae (4 %), 22 E. casseliflavus (3 %), 21 E. gallinarum (3 %), 17 E. durans-E. hirae complex (3 %), 5 E. durans (1 %), and 1 strain of E. avium. 150 strains were classified only as Enterococcus sp. (25 %) and 107 strains (17 %) isolated from Slanetz-Bartley agar were not enterococci. We found that the non-enterococcal group consisted of other Gram-positive cocci and Gram-positive and Gram-negative rods. Based on the identification we tried to find a relation between taxonomic position of isolated strains and their colony morphology on Slanetz-Bartley agar. Out of the total of 523 identified enterococci, 345 strains (66 %) formed purple colonies, 136 red colonies (26 %), 37 pink colonies (7 %) and 5 cream colored colonies (1%). There was no correlation among the color, size or colony morphology and the taxonomic characterization of enterococcal strains.