Studies on the Growth of Group D and other Streptococci in Different Media

Abstract

SUMMARY Growth obtained from pure cultures of 9 Streptococcus spp. in media containing different added chemicals revealed that thallium acetate was the least harmful to the generation rate of all test species. Sodium azide follows in that respect except for Strep. uberis. Potassium tellurite tends to produce marked reductions in the generation rate of some species and completely inhibits the log phase in others. The tellurite tolerant species include Strep. faecalis var. zymogenes, Strep. faecalis var. liquefaciens, Strep. pyogenes, Strep. agalactiae and Strep. uberis. The tested Strep. faecalis strain demonstrated an inhibition of the log phase at tellurite concentrations between 0.05 and 0.7%. Sensitive species failing to proceed in a log phase of growth in the presence of 0.01% tellurite concentration include Strep. durans, Strep. lactis and Strep. bovis. The highest number of cell recoveries from the sensitive species may be made at 6 h incubation.