Medical microbiology has traditionally studied pathogens in isolation, for example to understand how they evolve resistance to drugs. In contrast, in environmental microbiology, the community context -- the extent to which each species is affected by other microbes that surround them -- has always been in the foreground. In my lab, we study the underlying principles driving the ecology and evolution of small bacterial communities, remaining somewhat agnostic to whether we are studying a human pathogen or a bacterium that can remove an environmental pollutant. In my talk, I will illustrate how a small community of four bacteria that can remove environmental pollutant interact and evolve, drawing parallels to other toxic environments, such as those containing antibiotics. I will also show more recent work that is closer to the medical field: one study on the evolution of resistance in communities, and one showing how ecological principles can be used to suppress a pathogen as a complementary approach to administering antibiotics. My take-home message is that to control pathogens and their evolution, infection biology needs to better consider the ecological context in which pathogens live.