Streptoccocus canis is a leading pathogen in dogs with skin infections and bacterial keratitis as the most prevalent clinical manifestations. Increasing numbers of S.canis infections in Europe have led to a higher use of β-lactam antibiotics due to a lack of preventive measures. This project aims to provide a comprehensive approach in understanding molecular mechanisms for disease manifestation and increasing prevalence of S.canis.
Key objectives addressed in this project are determining genetic diversity and phylogenetic structure of 364 S.canis clinical isolates, as well as the identification of genes involved in pathogenicity and transmission. WGS followed by MLST enabled the identification of 2 dominant STs: 9, which is shared with feline and cattle hosts, and 43 which appears to be a canine focused ST. S.canis genes of these STs that influence colonization and disease manifestation in dogs will be identified by applying Transposon-Directed Insertion-site Sequencing as a functional-genomic approach. The resulting mutated bacteria will be sequenced before and after blood and skin colonization assays. Bacteria that have not survived the assays will correspond to the mutants of interest.
In conclusion, this approach will allow a better understanding of the virulence mechanisms of S.canis, which may enable the elaboration of new vaccines. This will further increase canine welfare and may give new insights into the invasive capacities of other streptococcal pathogens.