title: Effect of formalin on the survival of systemic fungi in tissue.
abstract: Stock cultures of Blastomyces dermatitidis, Candida albicans, Cryptococcus neoformans, Histoplasma capsulatum and Sporothrix schenckii were grown in yeast phase on Sabouraud dextrose agar. Standardized suspensions (10(8) colony forming units/ml) were made and 1. the organisms treated for various times with 10% formalin/acetate buffer; 2. aliquots injected into the tail veins of Swiss-Webster mice. Minimal fungistatic and fungicidal concentrations of formalin were also determined. Five minutes or more of formalin treatment killed all organisms, in vitro, except C. albicans which withstood the 5-minute but not the 30-minute treatment. All fungi, except H. capsulatum which was not recovered, were cultured from mouse heart, kidneys, spleen, lungs and liver prior to but not after 5-minute formalin treatment. All yeasts were susceptible to concentrations of less than 1% formalin. These results emphasize the extreme fungicidal activity of 10% formalin and the uselessness of culturing even very briefly-fixed tissue.
mesh_terms: D000818:Animals; D001203:Ascomycota / Q000187:drug effects*; D001758:Blastomyces / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D003455:Cryptococcus neoformans / Q000187:drug effects; D005557:Formaldehyde / Q000494:pharmacology*; D006658:Histoplasma / Q000187:drug effects; D051379:Mice; D003904:Mitosporic Fungi / Q000187:drug effects*; D013175:Sporothrix / Q000187:drug effects; D013997:Time Factors
chemical_list: D005557:Formaldehyde