First description of Mycobacterium heckeshornense infection in a feline immunodeficiency virus-positive cat

A 13-year-old cat was presented to the veterinary clinic with poor condition, vomiting and a reduced appetite. A painful abdomen was diagnosed because of tension and defence reactions on palpation. Diagnostic laparotomy showed a thickening of the colon and caecal intestinal wall. Histopathological investigation of intestinal biopsies revealed focal severe granulomatous inflammation with numerous acid-fast bacilli in the tela submucosa. The complete blood count test showed a severe lymphopenia and anaemia, and the cat tested positive for feline immunodeficiency virus (FIV) antibodies by enzyme-linked immunosorbent assay. The cat was euthanased and necropsied. Multifocal granulomatous nodules were present in the intestines, liver and kidneys. The gastric lymph node was markedly enlarged and showed a caseous cut surface. Histopathology revealed a systemic mycobacteriosis affecting intestine, lymph nodes, liver and kidneys. The mycobacterial strain was cultured and determined by its unique 16S rRNA gene sequence as Mycobacterium heckeshornense. This is the first reported case of M heckeshornense in a cat. It was suspected that the disseminated mycobacteriosis was supported by the FIV infection.