PATHOGENICITY OF YEASTS AND ALGAE ISOLATED FROM BOVINE MASTITIS SECRETIONS IN A MURINE MODEL

The pathogenicity of strains of yeasts and algae isolated from bovine mastitis secretions was evaluated in immunosuppressed mice. Strains of Candida tropicalis (n=3) were the most pathogenic, but all strains of Geotrichum capitatum (n=5) and the colourless alga Prototheca zopfii (n=5) were also lethal to mice at the highest dose of 1 x 10(7) CFU pe r mouse. Reisolation of the inoculated micro-organisms and the occurre nce of histopathological lesions within organs of mice challenged with 1 x 10(3) to 1 x 10(7) CFU per animal revealed strains of C. krusei ( n=17), C. kefyr (n=6) and C. rugosa (n=6) to have a moderate pathogeni city, whereas strains of C. valida (n=1) and C. catenulata (n=2) were weakly pathogenic and non-pathogenic respectively.