Pseudogranuloma inguinale caused by haemophilus ducreyi.

We used a new selective culture medium to isolate Haemophilus ducreyi from a penile ulcer that had the clinical appearance of granuloma inguinale. The isolation of the organism in pure culture permitted us to make a definitive diagnosis and obtain antimicrobial susceptibility data in a relatively short period. As a result, we were able to change therapy from sulfamethoxazole to erythromycin, and the infection rapidly healed.