Lactic acid bacteria from badgers display inhibitory activity to BCG

The use of the human tuberculosis vaccine, Bacillus Calmette-Guerin (BCG), in badgers has been suggested as a humane and long-term solution to reduce tuberculosis transmission from badgers to cattle. However, experimental studies show variable protection. Among the possibilities for this variation is that the resident gut bacteria may influence the success of oral vaccination in badgers; either through competitive exclusion and/or inhibition, or via effects on the host immune system. In order to explore this possibility, researchers tested whether typical gut commensals such as lactic acid bacteria (LAB) have the capacity to impact on the viability and survival rate of BCG. The findings of the research, funded by Morris Animal Foundation, are reported in BMC Microbiology.

Researchers at the University of Surrey, along with collaborators at the UK’s Animal and Plant Health Agency, isolated LAB from the faeces of European badgers (Meles meles). They found that some of these bacteria kill off the BCG vaccine, which could reduce its effectiveness in this species.

“As M. bovis is often excreted from infected badgers in their faeces, we might find a way to use these gut bacteria to kill M. bovis instead; a way of naturally reducing contamination of the badgers’ environment with the bacteria that cause TB,” said Jorge Gutierrez, University of Surrey researcher and lead author of the paper. “We also found the lactic acid from badgers was good at stimulating the badger’s immune system, which could be good news for improving the effectiveness of the vaccine.”

Current TB intervention measures in the United Kingdom includes controlling cattle movement, limiting cattle contact with wildlife in pastures as well as culling badgers. Keeping cattle away from wildlife is challenging for livestock managers. Also, badgers live locally within a social structure that can be disrupted by culling, leading badgers to travel further, taking the disease with them. An effective vaccine strategy would be optimal for all animals affected by this disease, as well as being an environmentally sound solution

“New long-term, environmentally friendly and sustainable solutions are needed both for the badgers and other animals affected by this disease,” said Dr. Gutierrez. “Our findings might explain in part why the BCG vaccine has variable results in badgers but also points to a possible future solution. There’s still a lot to learn about the bacteria that make up the natural flora of the badger gut.”

Recently, Dr. Gutierrez and his wildlife management collaborator, the Spanish company Ingulados, isolated beneficial gut bacteria from wild boars, another TB reservoir species in parts of mainland Europe. They are exploring its use to naturally and safely help mitigate bovine TB spillover in Spain.

Article: Lactic acid Bacteria isolated from European badgers (Meles meles) reduce the viability and survival of Bacillus Calmette-Guerin (BCG) vaccine and influence the immune response to BCG in a human macrophage model by Anna Stedman, Carlos Maluquer de Motes, Sandrine Lesellier, Deanna Dalley, Mark Chambers and Jorge Gutierrez-Merino published in BMC Microbiology (2018) 18:74, doi: 10.1186/s12866-018-1210-z

[SOURCE: Morris Animal Foundation]