Mycobacterial safety of meat cuts from BCG-vaccinated African buffaloes (Syncerus caffer) experimentally infected with Mycobacterium bovis

Abstract

Tuberculosis is a global disease that affects humans and animals, both wild and domestic. Bacteria, of closely related sub-species, from the Mycobacterium tuberculosis complex are what cause tuberculosis (TB). There are two main forms of the disease: the human disease, mainly caused by Mycobacterium tuberculosis and the animal disease, caused predominantly by Mycobacterium bovis and Mycobacterium caprae. The animal form of the disease can be zoonotic, particularly M. bovis. The study was a qualitative study that set out to determine the safety of meat cuts (fillet, silverside, brisket, and rump) taken from vaccinated (inactivated M. bovis vaccine and BCG) and experimentally infected buffaloes with M. bovis in particular, for the presence of M. bovis and M. bovis BCG. The different cuts of meat were chosen due to their popularity in the consumer markets. The animals were held at the Skukuza bomas and were euthanised and full post mortem examinations were conducted in October 2021 at the Skukuza abattoir. Meat samples were collected at the abattoir and biobanked until the samples were needed for a study. The meat samples were then processed at Hans Hoheisen Wildlife Research Station, Orpen Gate, Kruger National Park, in February 2023. The methodology involved the culture of samples from different meat cuts (fillet, brisket, silverside and rump), on mycobacteria-selective media. In this study, a total of 378 media slopes were produced of which only ten showed colony-like growth. Speciation by PCR was conducted on these ten media slopes. The data were analysed by creating pivot tables. Pivot tables enable large amounts of data to be summarised in an easy and understandable format. The study concluded that the meat from vaccinated and experimentally infected buffaloes showed no positive results for M. bovis or M. bovis BCG. These results suggest that meat collected from vaccinated and experimentally infected buffaloes is likely to be safe for humans to consume, but larger sample sizes are needed to increase certainty.