Experimental murine mycotic mastitis: a sensitive and lenient model for studies of antifungal chemotherapy

The murine model of mycotic mastitis was used to study the efficacy of amph otericin B (AmB). Twenty-four BALB/cJ mice at the fifth day of lactation we re anesthetized and inoculated through the teat I-anal (two glands) with 50 mu l suspension containing 5.0 x 10(7) cfu ml(-1) Candida albicans blastos pores. Mice were randomly divided into two groups: untreated controls and A mB treated. Animals were euthanized 3 and 6 days after infection and treatm ent (4 mg kg(-1) per day intraperitoneally). The fungal burden of the mamma ry gland was determined by quantitative cultures. The number of C. albicans cells recovered from mammary gland homogenates were significantly lower in the AmB treated animals (both 3 and 6 days post-infection) than in the unt reated controls (P < 0.007 and P < 0.003, respectively). The mammary glands of all untreated control animals showed marked neutrophilic infiltration, severe necrosis, and presence of blastospores, hyphae and pseudohyphae. In contrast, 10 of 12 animals treated with AmB showed only a mild neutrophilic infiltration which was restricted to alveoli and excretory ducts. All extr a-mammary organs were free of infection in both groups. The results demonst rate that the murine mycotic mastitis model is suitable for investigations of new antifungal compounds. In addition, this model is more lenient than t he systemic candidiasis models. (C) 1999 Federation of European Microbiolog ical Societies. Published by Elsevier Science B.V. All rights reserved.