Metabolomic changes in the peripheral blood of wild trapped badgers (Meles meles) correlate with bovine tuberculosis (Mycobacterium bovis) infection status

BACKGROUND: Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is the most significant infectious disease of UK cattle. Badgers (Meles meles) can also be infected by M. bovis and may act as a source of infection for cattle. Management of infection risks could be supported by the availability of sensitive blood tests for bTB in badgers. We explored whether metabolomic changes in peripheral blood could be used for the diagnosis of bTB in wild, naturally infected badgers.

METHODS: Flow infusion electrospray - high-resolution mass spectrometry (FIE-HRMS) was used to assess the peripheral blood of trapped wild badgers (n = 148) for metabolite changes linked to bTB infection status. Infection status was established by culture, Dual Path Platform (DPP) and interferon (IFN-γ) blood tests or mycobacterial culture. Data were analysed by multivariate and receiver operating characteristic (ROC) curve analyses.

RESULTS: Metabolite shifts were identified in badger blood samples associated with their corresponding infection status. Biochemical pathway analyses suggested that sphingolipid and glycerophospholipid metabolism was enriched in bTB badgers. However, some individual metabolites changes appeared to differ depending on badger sex.

CONCLUSION: Our data shows that metabolomic assessment of peripheral blood can indicate bTB infection status. However, larger sample sizes are required to establish if our metabolites have potential as diagnostic biomarkers.