Streptococcal population profiles as indicators of water quality

The streptococcal flora of two sewage treatment facilities, lakewater receiving effluent from a sewage treatment facility, and the feces of five animals were examined. An improved medium, designated M2 allowed the isolation of a total of 3314 streptococcal strains representing 17 species. Thirteen of these species were assembled into groups based upon similarities in ecology or physiology. Comparison of the proportions of these groups within samples from various sources allowed populations from human sources to be distinguished from animal derived populations. Finally, the streptococcal populations of three streams were examined and the concept of environmentally significant groups applied to define the types of contamination present.