Mycobacterium nonchromogenicum in nasal mucus from cattle in a herd infected with bovine tuberculosis

• Published in: Veterinary microbiology 2004-04, Vol.99 (3), p.281-285
• Main Authors: McCorry, T.P., McCormick, C.M., Hughes, M.S., Pollock, J.M., Neill, S.D.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Bacterial - blood; Bacterial diseases; Biological and medical sciences; blood; Bovine; bovine tuberculosis; Cattle; Cattle Diseases - immunology; Cattle Diseases - microbiology; DNA; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; herds; Human bacterial diseases; Infectious diseases; interferon-gamma; Medical sciences; Microbiology; mucus; Mycobacterium - genetics; Mycobacterium - growth & development; Mycobacterium - immunology; Mycobacterium bovis; Mycobacterium Infections - immunology; Mycobacterium Infections - microbiology; Mycobacterium Infections - veterinary; Mycobacterium nonchromogenicum; Mycobacterium tuberculosis; Nasal Mucosa - microbiology; Nasal mucus; nose; PCR; polymerase chain reaction; Polymerase Chain Reaction - veterinary; radiometry; ribosomal RNA; risk; RNA, Ribosomal, 16S - chemistry; RNA, Ribosomal, 16S - genetics; sequence analysis; Skin test; Skin Tests - veterinary; tuberculin; Tuberculosis and atypical mycobacterial infections
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2003.12.006

Skin test negative cattle from a herd containing an unusually high proportion (194/382) of tuberculin skin test positive cattle were investigated for remaining Mycobacterium bovis infected animals. Blood samples from the skin test negative cattle, analysed by an antibody ELISA and an interferon-gamma assay, were mostly test negative for M. bovis. Radiometric culture of nasal mucus samples from 48 of the cattle yielded 22 culture positives with acid-fast bacilli and cording in 6 of these. Subculture on solid media was successful for 7, including 2 with cording of the 22 radiometric culture positives. Mycobacterium tuberculosis complex DNA probe testing using the Accuprobe (Gen-Probe, Inc.) and M. tuberculosis complex-specific PCR amplification, performed on the solid media subcultures, were negative. 16S rRNA PCR and sequence analysis were successful for 6 of the 7 solid media subcultures obtained and revealed the presence of Mycobacterium nonchromogenicum in all 6 subcultures. This is the first report of M. nonchromogenicum in nasal mucus of cattle. The observation highlights the importance of integrating definitive tests such as the PCR for diagnosis of bovine tuberculosis and indicates a possible zoonotic risk.