Susceptibilities of Clinical and Laboratory Isolates of Blastomyces dermatitidis to Ketoconazole, Itraconazole, and Fluconazole

Abstract

Eighteen isolates of Blastomyces dermatitidis were evaluated for their in vitro susceptibilities to ketoconazole, itraconazole, and fluconazole. The MIC ranges were 0.1 to 0.4 g/ml for ketoconazole, <0.018 to 0.07 g/ml for itraconazole, and 2.5 to 4.0 g/ml for fluconazole. The ranges for the minimal lethal concentrations were 0.2 to 0.8 g/ml for ketoconazole, <0.018 to 0.07 g/ml for itraconazole, and 10 to 40 g/ml for fluconazole. Itraconazole was the most active agent against B. dermatitidis in vitro, while fluconazole was the least active. These results correlate with the clinical efficacies noted to date with doses of these agents used to treat blastomycosis.

Cutaneous blastomycosis: a diagnostic challenge

“…Itraconazole is the drug of choice among available azole antifungal agents to treat mild‐to‐moderate disseminated disease without CNS involvement 43 . For these patients, 90% cure rates have been reported after a 6‐month regimen of 200–400 mg/d itraconazole 44 .…”

Fungal infections of the lung

“…A study comparing in vitro susceptibilities of B. dermatitidis to ketoconazole, itraconazole, and fluconazole clearly showed that itraconazole was the most active of this group against B. dermatitidis, whereas fluconazole was least active [26]. In acute disease, the patient may be observed if clinical improvement is noted, if not, treatment with itraconazole 200 mg po bid for 6 months may be begun.…”

Antifungal agents of use in animal health – chemical, biochemical and pharmacological aspects

“…Ketoconazole is also active against B. dermatitidis ( MIC range: 0.1–04 mg/L) (Chapman et al ., 1998), H. capsulatum (0.39 mg/L) and some isolates of C. immitis (0.39 mg/L) (Shadomy et al ., 1985). However, for other C. immitis isolates more than 100 mg/L was needed (Shadomy et al ., 1985).…”

“…Itraconazole had MIC 90s ( MIC at which 90% of the isolates are inhibited) of 0.06 mg/L for H. capsulatum , 0.125 mg/L for B. dermatitidis and 1 mg/mL for C. immitis . Using the macrobroth dilution susceptibility test to evaluate the activity of itraconazole against B. dermatitidis isolates, Chapman et al . (1998) found an MIC range of ≤0.018–0.07 mg/L.…”

“…Chapman et al . (1998) found an MIC range of 2.5–4 mg/L for B. dermatitidis , whereas the MIC range was ≤0.018–0.07 mg/L for itraconazole.…”