Streptococcus suis is a common pig pathogen colonising nearly all pig farms. While hardly lethal in pigs, S. suis still causes large economic losses to the swine industry because infected meat cannot be sold. Moreover, S. suis is extremely dangerous for meat industry workers, because when transmitted to humans it causes meningitis in 80% of patients and deafness in 60% of recovered casualties. Unfortunately, neither a vaccine nor diagnostic tool against S. suis is available, therefore the development of alternative control is an utterly important task. To develop such methods, detailed understanding of how the pathogenicity of S. suis evolved is required. Depending on whether pathogenicity evolved via the lack of recombination ability or the lack of recombination opportunity interventions based on increased biosecurity or the use of antimicrobials, blocking horizontal gene transfer may be preferable. In my PhD, I aim to produce a comprehensive model of how restricted recombination is involved in emerging pathogenicity and thus contribute to food safety and sustainability by facilitating the design of novel treatment strategies.