Distribution and characterization of Enterococcus species in municipal sewages

The occurrence, distribution and characterization of enterococci in municipal sewages from two geographically different regional sewage treatment plants in East Slovakia was studied. The total counts of enterococci in samples varied from 10(4) to 10(6) CFU/ml. The vast majority of the strains identified were Enterococcus faecium (50%), with E. gallinarum (25.5%) and E. casseliflavus (10.1%). The species which accounted for 14.4% of the cultures were not specified. Lactic acid production from twenty isolates ranged from 0.085 mol l-1 to 0.914 mol l-1. Urease activity ranged from 1.21 nkat ml-1 to 10.49 nkat ml-1. The strains were resistant to at least one (except for vancomycin) and at most to six antibiotics tested. The majority of isolates were biresistant. Although nine strains were without bacteriocin production, the other strains inhibited the growth of enterococcal as well as staphylococcal isolates. E. faecium AL 40 produced bacteriocin which inhibited the growth of all indicators reaching 12 mm zones of inhibition. E. faecium was the most prevalent species in all samples, but the source position of isolates as well as the sewage composition did not affect enterococcal distribution. The ability of isolates to produce bacteriocin indicates their possible use in biotechnological environmental processes.