Rapid detection of Mycobacterium bovis in bovine cytological smears and tissue sections by peptide nucleic acid fluorescence in-situ hybridization

•FISH detection of mycobacteria with oligonucleotide probes is difficult because of long-chain mycolic acids in cell walls.•·With a fluorescein-labeled PNA probe one can differentiate between tuberculous and nontuberculous mycobacteria.•·ISH, histopathology and PCR are either non-specific, time consuming, or do not distinguish single mycobacteria.•·PNA-FISH proves to be an improvised method for fast visualization and identification of M. bovis and M. avium.