Abstract
Summary
The dissociation among 130 bovine and 26 human strains of Lancefield's group “B” streptococci has been studied. Four different morphological types of colonies (rough, smooth, mucoid and smooth-ravined) are discarded in detail. No correlation was found between colonial morphology and the biological properties and susceptibility to penicillin. All strains were resistant to streptomycin in vitro. Cultures from rough out-growths of mouse virulent mucoid parent colonies were completely avirulent for mice. Formamide extracts of mucoid, smooth and smooth-ravined cultures reacted positively in precipitin tests with homologous and heterologous rabbit serums prepared with mucoid, smooth and smooth-ravined cultures and with commercial group “B” serum. Formamide extracts prepared from rough cultures always gave negative precipitin tests with good precipitating rabbit serums prepared with the corresponding mucoid, smooth and smooth-ravined parent cultures.
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