The influence of penicillin on growth and morphology of Streptococcus pyogenes in vivo.
The influence of penicillin (pc) on the growth, phagocytosis and killing of Streptococcus pyogenes was studied for an M protein positive (M+) and an M protein negative (M-) strain in vivo as well as in vitro. In vivo studies were based on a tissue cage model and the analyses were performed by CFU determinations and electron microscopic investigations. The M- strain was easily phagocytized with and without pc, but killing only occurred after pc treatment and thus the number of viable bacteria rapidly decreased under the influence of pc. M+ streptococci were not reduced in numbers by pc-treatment in vivo, but morphological changes and at high pc concentrations, phagocytosis could be seen. When this strain (M+) was cultivated in the absence of pc, the phagocytic cells were totally destroyed - a reaction that was prevented by penicillin. Variations in surface morphology of the two strains seem to influence the differences in sensitivity to penicillin, phagocytosis and killing.
D000818:Animals; D001433:Bacteriolysis; D002473:Cell Wall / Q000648:ultrastructure; D006801:Humans; D008854:Microscopy, Electron; D009504:Neutrophils / Q000382:microbiology / Q000502:physiology*; D010400:Penicillin G / Q000494:pharmacology*; D010587:Phagocytosis; D011817:Rabbits; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure
D010400:Penicillin G