Isolation of Mycobacterium bovis and other mycobacterial species from ferrets and stoats

As part of wildlife surveillance for bovine tuberculosis, pooled lymph nodes from 21,481 ferrets, 1056 stoats and 83 weasels were cultured for mycobacteria. A total of 268 isolates of Mycobacterium bovis were obtained from ferrets, 2 from stoats and none from weasels, demonstrating the presence of a wildlife reservoir of infection in ferrets. DNA typing by restriction endonuclease analysis (REA) of 48 selected isolates of M. bovis revealed 23 REA types. Twenty-one of these types had previously been isolated from cattle and farmed deer, demonstrating a complex cycle of infection involving wildlife and domestic animals. Apart from M. bovis, a further 208 mycobacterial isolates were obtained, the majority of which (178) were members of the M. avium complex. Speciation of the remaining 30 mycobacterial isolates by DNA sequencing of the 16s rRNA gene, identified half the isolates as M. triplex. Other species identified included M. fortuitum, M. florentinum, M. interjectum, M. intracellulare, M. holsaticum, and M. septicum/M. peregrinum.