SUMMARY
An actinomycete was isolated in large numbers from a penile ulcer.
The actinomycete isolated was assigned to the genus Nocardia since it produces a ray-type mycelial colony with clubs, curls and branches, it fragments into coccoid and bacillary forms, it is Grampositive and partially acid-fast.
This organism differs from previously described species of Nocardia. Since it shows a striking fastidiousness in its growth requirements, the designation Nocardia fastidiosa n. sp. is recommended.