New research has shed light on how a badger’s natural gut bacteria could play a role in protecting both them and cattle from tuberculosis (TB).
Researchers wanted to know why experimental studies into oral vaccination with the attenuated Mycobacterium bovisvaccine BCG to reduce TB infection in badgers have demonstrated variable protection levels.
Among the possibilities for the variation is the resident gut bacteria could influence the success of oral vaccination in badgers – either through competitive exclusion and/or inhibition, or via effects on the host immune system.
To explore this possibility, scientists tested whether typical gut commensals, such as lactic acid bacteria (LAB) have the capacity to impact on the viability and survival rate of BCG, and to modulate the immune response to BCG using an in vitro model.
Results of the work, funded by the Morris Animal Foundation and published in BMC Microbiology, found gut bacteria from badgers may be decreasing the effectiveness of the BCG vaccine, but at the same time, killing off M bovis.
Jorge Gutierrez, University of Surrey lecturer in food microbiology and lead author of the paper, and his team, working in conjunction with the APHA, isolated several types of natural gut bacteria – specifically, LAB – from the faeces of badgers.
Dr Gutierrez said: “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.
“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.”

Beneficial bacteria

Kelly Diehl, interim vice-president of scientific programmes at the Morris Animal Foundation, said: “All animals, including humans, contain both beneficial and harmful bacteria.
“Unfortunately, harmful bacteria get all the press as these microbes can make us sick or trigger large-scale disease outbreaks.
“Dr Gutierrez’s work is a superb example of how we might be able to use the beneficial bacteria already living in our bodies in novel ways to help combat diseases such as bTB.”