Antimicrobial susceptibility patterns of fungi isolated from horses with ulcerative keratomycosis.

OBJECTIVES: To evaluate in vitro susceptibility to topical antifungal medications, as measured by minimum inhibitory concentration (MIC) and 50% inhibitory concentration (IC50%), of fungal isolates from horses with ulcerative keratomycosis in Florida; to compare results with those of other studies to identify differences in susceptibility patterns among fungi isolated from horses in different geographic regions; and to note indications of fungal resistance to drugs tested in other studies. SAMPLE POPULATION: Corneal fungal cultures from client-owned horses from Florida with ulcerative keratomycosis (n = 22). PROCEDURE: Fungal cultures were plated on Emmons modified Sabouraud dextrose agar and mycobiotic agar, examined weekly for growth, and kept for a total of 30 days. In vitro MIC and IC50% of fluconazole, itraconazole, ketoconazole, miconazole, and natamycin were measured for each fungal isolate. RESULTS: Aspergillus (n = 9; 41%), Fusarium (7; 32%), Penicillium (2; 9%), Cylindrocarpon (1; 4%), Scytalidium (1; 4%), and Torulopsis (1; 4%) spp and an unidentified yeast (1; 4%) were isolated. Fungi were most susceptible to antifungal drugs in the following order: natamycin and miconazole equally, itraconazole, and ketoconazole, although no significant difference was found among drugs. Fungi were significantly less susceptible to fluconazole (P < 0.0001) than to the other 4 drugs. CONCLUSIONS: Initial antifungal therapy with topically applied natamycin, miconazole, itraconazole, or ketoconazole is recommended for ulcerative keratomycosis in horses in the subtropical environment of Florida. CLINICAL RELEVANCE: Specific antifungal treatment of horses with ulcerative keratomycosis should be based on history, results of ophthalmic examination, cytologic findings, isolation of the pathogenic fungus, and known prevalence of unique ocular fungi in specific geographic areas. In vitro antifungal susceptibility testing may be most beneficial in aiding documentation of pharmacologic susceptibility patterns of fungi in specific geographic regions.

Diagnosis, treatment, and temporary remission of disseminated paecilomycosis in a vizsla.

A case of disseminated paecilomycosis in a three-year-old vizsla is described. Clinical signs of lethargy, weight loss, lymphadenopathy, diarrhea, and vestibulocochlear deficits were exhibited. Dense colonization of bone marrow by the fungus was found early in the disease course. Serial culture of bone-marrow aspirates and in vitro sensitivity testing helped monitor disease progression and guide antifungal therapy. Clinical and laboratory parameters demonstrated marked improvement for a period of 12 weeks. Multisystemic disease with central nervous system involvement was found at necropsy.

Cutaneous Rhizopus infection. Occurrence as a postoperative complication associated with an elasticized adhesive dressing.

A 29-year-0ld woman in good health except for scoliosis suffered severe sequelae during the postoperative course for placement of a Harrington rod. A cutaneous Rhizopus infection in and about the incision site was attributed to the use of a contaminated elasticized adhesive (Elastoplast) dressing. The comtamination was established as a nosocomial problem, which is extremely difficult to control. The extent of the infection, subsequent long recovery course, and remarkable sequelae make this case unusual.

Diagnostic medium containing inositol, urea, and caffeic acid for selective growth of Cryptococcus neoformans.

An agar medium containing inositol and urea as sole carbon and nitrogen sources, caffeic acid and ferric citrate as agents for the selective pigmentation of Cryptococcus neoformans, gentamicin as a broad-spectrum bacterial antibiotic, and yeast nitrogen base without amino acids and ammonium sulfate (Difco) was tested against 137 clinical isolates, 4 survey specimens, and 11 ATCC yeast and yeast-like strains. All 28 strains of C. neoformans showed heavy growth and dark brown pigmentation after 36 h. All other tested species of Cryptococcus showed heavy growth after 36 h but only light brown pigmentation after 48 h. No growth was observed in any tested strains of Geotrichum, Pityrosporum, Rhodotorula, Saccharomyces, and Torulopsis. Only the Cryptococcus-like Candida humicola grew of the 8 species and 62 strains of Candida tested. Six of 15 strains of Trichosporon cutaneum and 1 of 2 strains of Trichosporon pullulans showed moderate growth after 48 h. Very different colonial and microscopic morphology and/or the absence of brown pigmentation easily differentiated these strains of T. cutaneum, T. pullulans, and C. humicola from C. neoformans. The growth- and pigmentation-providing characteristics of the medium were unaffected by 2 h of exposure to 254 nm of ultraviolet light.

Identification of carbon dioxide as a dermatophyte inhibitory factor produced by Candida albicans.

A factor produced by Candida albicans, which inhibits dermatophyte growth and induces arthrospore formation is characterized and identified. Candida dermatophyte inhibitory factor (CDIF) is volatile and fungistatic. Analysis of volatile materials produced by C. albicans was subsequently identified as carbon dioxide. The involvement of carbon dioxide in the inhibition of dermatophytes was demonstrated by: (1) utilization of commercial carbon dioxide to produce dermatophyte inhibition as well as arthrospore formation, and (2) prevention of dermatophyte inhibition by C. albicans through incoporation of soda lime into the incubation atmosphere. The ability of carbon dioxide to inhibit dermatophyte growth was shared with other gases (methane and helium), but arthrospore formation was observed only with carbon dioxide. The possible significance of carbon dioxide's induction of arthrospores, a form occasionally observed in active dermatophyte lesions, is discussed.