Untyped forms of faecal streptococci in Egyptian sewage and Nile water.

When the thallous-azide agar medium was used a higher incidence of pure faecal streptococci recovery was recorded especially from slightly polluted vehicles such as river water than on the standard M-enterococcus agar medium. In addition, a thallous-azide combination at pH 6.5 was used successfully for the primary isolation of Str. faecalis and its two variants. Results of biochemical tests of 274 faecal streptococci isolates showed that 20% belonged to Str. faecalis and its two variants as well as Str. durans, Str. faecium and Str. equinus. Thirty-eight percent of the isolated strains were classified as atypical I, II, III, and V previously designated by COOPER and RAMADAN (1955) as well as the unclassified group of RAMADAN et al. (1972). While the remaining 42% were found to belong to seven different categories (SALEH 1976 and 1977). The correlation between four differential tests used for defining the source of faecal streptococci isolates was discussed.