Synergism of Candida albicans and delta toxin producing staphylococcus aureus on mouse mortality and morbidity: Protection by indomethacin

Twelve Staphylococcus aureus strains, six positive and six negative for δ-toxin production, were studied for synergistic effects on mouse mortality and morbidity when combined with Candida albicans and inoculated intraperitoneally (i.p.). S. aureus strains producing δ-toxin were found to exhibit a relatively great synergistic decrease (between near 10³–10⁵-fold) in LD₅₀ (dose necessary to kill 50% of exposed animals in five days) when combined with a nonlethal dose of C. albicans and injected i.p. S. aureus strains which did not produce δ showed less of a synergistic effect with C. albicans (10–10²-fold drop in LD₅₀). A synergistic effect on mortality could also be produced when animals were dually injected with C. albicans and sterile growth filtrates from the δ-toxin producing strains or the purified δ-toxin. The lethal agent in the culture filtrate was, like δ-toxin, sensitive to lecithin and insensitive to heat. Indomethacin protected animals from the C. albicans-filtrate induced death. Blood measurements made following i. p. injection of δ-toxin and C. albicans revealed chemistry changes indicative of shock, kidney and liver damage; δ-toxin alone caused no significant chemistry changes whereas C. albicans alone caused some blood chemistry changes but liver and kidney damage was not indicated. No synergism on mortality was found between C. albicans and purified α-toxin or toxic shock syndrome toxin-1.