Etiological agents of mycobacterioses in pet birds between 1986 and 1995

Between May 1986 and June 1995, mycobacteriosis was diagnosed by histology and microscopy in 204 (3.8%) of 5,345 necropsied pet birds. The predominant macroscopic changes were enlargement of the liver and spleen and thickening of intestinal walls. Attempts to cultivate mycobacteria were made in 110 cases. Acid-fast bacilli grew in 66 specimens (60%) only. In 18 cases we failed to obtain subcultures. Therefore, species identification could be performed for only 48 isolates. Identification was carried out by conventional biochemical tests as well as by PCR-mediated sequencing of the 16S rRNA gene. The majority of the isolates were Mycobacterium genavense (34 isolates), followed by M. avium complex(8), M. fortuitum (2), M. tuberculosis (2), M. gordonae (1), and M. nonchromogenicum (1). The significance of M. genavense as a zoonotic agent remains to be determined.