Genomic and phenotypic characterisation of Pseudomonas aeruginosa isolates from canine otitis externa reveals high-risk sequence types identical to those found in human nosocomial infections

For the first time, this study has characterised a large multinational collection of <i>P. aeruginosa</i> isolates from canine otitis with a combination of whole genome sequencing, phenotypic screening and bioinformatic analysis. These strains did not cluster together based on genomic diversity or virulence gene complement, supporting their likely environmental origin. However, the identification of ST111 and ST244, important 'high-risk' sequence types, could suggest potential spread between humans and dogs. Furthermore, we found that most strains were formed strong biofilms, and exhibited a significant level of resistance towards critically important antimicrobials. These findings could assist in the selection of appropriate treatments for canine OE as well as possibly identifying one health risks of these infections for cohabiting pets and humans.