Mycobacterium africanum and nontuberculous mycobacteria from fresh milk of pastoral cattle and soft cheese in Oyo State--implications for public health.

BACKGROUND

Milk and.milk products from cattle in tuberculosis endemic countries like Nigeria where pasteurization is not enforced could be a source of health concerns to the consumers.

METHODS

We assessed randomly selected fresh milk from pastoral cattle, cheese samples and sour milk (nono) for the presence of Mycobacterium species through cultural isolation, Multiplex Polymerase Chain Reaction (PCR) and PCR-restriction enzyme analysis (PRA)-hsp65.

RESULTS

Out of 269 fresh milk, 295 cheese and 150 sour milk samples screened; 8.30%, 0.34% and 0.00%, respectively were positive for Mycobacterium species. Molecular characterization revealed three M. africanum (fresh milk = 2; cheese = 1) and a high prevalence of Non-tuberculous Mycobacterium (NTM; 89.29%) from fresh milk comprising M. gordonae (n = 12), M. fortuitum (n = 4), M. senegalense (n = 7) and M. avium (n = 1).

CONCLUSION

The isolation of M. africanum and NTM species from this study is a matter of public health concern considering the practice of pooling milk from different animals and the consumption of unpasteurized milk which characterize most pastoral communities in Nigeria. Given the predominance of NTM in this study, their potential to cause disease in humans should not be ignored. Urgent measures should also be taken to integrate molecular techniques that will differentiate NTM from members of the M. tuberculosis complex in the epidemiology of tuberculosis in order to avoid misdiagnosis in humans and thereby protect public health.