First report on isolation of Listeria ivanovii from a cat

Several Listeria species cause listeriosis. Listeria monocytogenes is responsible for the majority of clinical cases in animals. A less frequently isolated species is Listeria ivanovii, which causes infections mainly in ruminants, most often associated with reproductive disorders, such as abortions, stillbirths, or neonatal mortality. Sporadic infections with this microorganism have been described in other animal species; however, no literature data, to our knowledge, describe the infection of L. ivanovii in cats.

L. ivanovii was isolated from tissue samples collected from a kitten with symptoms of acute catarrhal gastroenteritis. Fragments of the liver, spleen, kidneys, and small intestine were collected post-mortem for microbiological examination. The isolated microorganism was identified as L. ivanovii based on its phenotypic properties and 16 S rRNA sequencing. The identification of subspecies L. ivanovii subsp. ivanovii was performed by comparative analysis of the sigB gene sequences.

Listeria ivanovii, which is more commonly known as a ruminant pathogen, can also cause severe infections in cats. This is, to our knowledge, the first report on the isolation of this microorganism from internal organs in a cat. This finding underscores the importance of careful interpretation of isolation results when uncommon pathogens are involved, particularly in host species where their pathogenicity has not been previously documented.