Microbes engage in a remarkable array of social behaviors, secreting shared proteins that are essential for foraging, shelter, microbial warfare, and virulence. These proteins are costly, rendering populations of cooperators vulnerable to exploitation by nonproducing cheaters arising by gene loss or migration. In such conditions, how can cooperation persist?  

Results/Conclusions

I review a series of models and data highlighting the importance of spatial structure in determining microbial social behaviours and consequent virulence, and highlight the peculiar role and importance of microbial mobile elements (plasmids, phages) in generating this structure. Finally, I discuss the possible therapeutic implications of understanding the social dynamics of microbial pathogens.