First Detection of Lactococcus petauri in Domestic Dogs in Italy

Lactococcus garvieae has been considered for a long time the only causal agent of lactococcosis. In recent years, different papers reported the involvement of other two bacterial species: Lactococcus petauri and Lactococcus formosensis. A different host tropism has been described for these species where L. garvieae and L. petauri are predominant species in fish and humans’ infections, while L. formosensis in bovine. L. garvieae has been reported as rare infectious agent in dog. This paper represents the first isolation of L. petauri in two domesticated dog cases from urine and skin samples, respectively. The recovered L. petauri has been identified using PCR and sequencing based on Internal Transcribe Spacer (ITS) and phylogenetic analysis showed that it belongs to the L. petauri cluster with a 100% of identity with sequences previously reported from fish isolates while there were differences with L. petauri isolated from urinary tract infection from humans. L. petauri in human infection has been considered not necessarily deriving from the ingestion of contaminated food but rather as an opportunistic pathogen colonization intestinal tract. Differences among virulotypes have been reported for humans and dogs, and a comparison was also made between the virulotyping of L. petauri and L. garvieae in dogs. The antimicrobial pattern showed susceptibility for the election treatment molecules. These data contribute to our understanding of the host trophism of this species which was misclassified for long time and provide new data on its virulence factors and antimicrobial resistance.