The effect of medium volume and yeast extract diffusate on delta-hemolysin production by five strains of Staphylococcus aureus.

Abstract

High concentrations of δ–hemolysin were formed by Staphylococcus aureus CN 4108, CN 6730 and CN 6729 growing in 10 ml of medium in baffled shake flasks (100 ml); larger volumes of medium under identical conditions led to the formation of much lower levels of toxin. Formation of the immunologically‐distinct δ–hemolysin by canine strains CN 7450 and CN 7442 was inhibited when only 10 ml of medium was used in the shake flasks; the toxin was formed when 20 or 30 ml of medium was used. High levels (40% v/v) of yeast extract diffusate in CCY medium were found to inhibit the formation of δ–hemolysin from strains CN 6729 and CN 7442. Strains CN 6730. CN 4108 and CN 7450 required at least 20, 30 and 40% (all v/v) YED respectively for optimum production of δ‐hemolysin. Strains CN 4108 and CN 7450 both formed δ‐hemolysin in late log phase.