Granulomatous dermatitis caused by Mycobacterium genavense in two psittacine birds.

Two cases of cutaneous mycobacteriosis in psittacine birds showing featherless, non-painful, non-pruritic nodules are described. Histopathological studies of skin biopsies from both cases demonstrated the presence of a diffuse granulomatous dermatitis with acid- fast organism s inside macrophages, which led to the diagnosis of cutaneous mycobacteriosis. In one case, generalization of the process to internal organs (intestinal and hepatic serosae) was observed. Mycobacterial organisms could not be cultured using conventional isolation media (Coletsos and Löwenstein-Jensen), but polymerase chain reaction (PCR) technique performed on pathological samples from both birds revealed the presence of Mycobacterium genavense. It is thus proposed that cutaneous mycobacteriosis infections, in particular those caused by M.genavense, should be included in the differential diagnosis of skin nodular processes in psittacine birds. The usefulness of PCR techniques for aetiological diagnosis of mycobacterial infections is emphasized.