Protection by Candida albicans of Staphylococcus aureus in the establishment of dual infection in mice.

Candida albicans has been shown to stimulate infection in mice by a number of bacteria when both organisms are inoculated intraperitoneally (E. Carlson, Infect. Immun. 39:193-197, 1983). When subcutaneous and intraperitoneal inoculations were given with Staphylococcus aureus and C. albicans injected at opposite sites, mixed infection was established at the site of fungal inoculation but not at the site of the bacterial injection. Histopathologic evaluation of tissues for the presence of C. albicans and S. aureus after intraperitoneal inoculation of both showed fungal growth in the mesentery and omentum of the abdominal cavity. Cocci were numerous and always associated with the fungi, located within the fungal growth rather than at its periphery. It was concluded that this growth pattern in some way protected the bacteria and was the basis for the generalized fungal stimulation of the bacterial infections observed. In addition to C. albicans, Candida stellatoidea, Candida tropicalis, Candida parapsilosis, Torulopsis glabrata, and heat-inactivated C. albicans also demonstrated some ability to protect bacteria injected simultaneously, although C. parapsilosis and T. glabrata were less effective than the other yeasts in this respect.