In the context of pathogenicity islands, what do virulence genes do?

Virulence genes are specific genes present in pathogenicity islands that directly contribute to the ability of bacteria to cause disease. These genes may encode various factors such as toxins, adhesion proteins, and invasiveness determinants that help the bacteria invade host tissues, evade the immune system, and establish infections. By enhancing the bacteria's capability to infect and damage host tissues, these virulence genes play a critical role in the pathogenicity of certain bacterial strains. This makes option C the most accurate choice, as it's focused on the direct connection between these genes and the bacteria's ability to cause disease.