Microbes have an enormous impact on our lives whether we see them or not. Overwhelmingly, this is a positive impact. Our own bodies are the bedrock for many unique microbial ecosystems that help to keep us healthy. Microbes produce many of our favorite foods, most valuable medicines and most of the oxygen we breathe. They clean human waste and pollution and are the foundation of the global ecosystem. There is also an infinitesimally small minority of microbes (relative to all microbial species on Earth) that causes sickness in humans. Nevertheless, these pathogenic species have serious and sustained negative impact on human society.
In every case, both positive and negative, individual microbes do not create such tangible impacts alone. During infection and within a healthy human microbiome, populations of millions or billions of microbial cells are cooperating and competing within mixed or single-species communities. During infection for example, pathogenic species often combine the activities of a single cell; many of the social or interactive capacities of these species are also factors associated with pathogenicity.
Basic research of microbial communities and collective behaviors helps us to understand the microbial communities that drive Earth’s biogeochemical cycles and make our foods and medicines. Microbial communities help us to learn how cells organize together and how multicellularity and social behaviors evolve. Genetic engineering of microbes in communities is also forming the foundation for a new age of bioindustry. On the other side, circumventing the ability of microbes to form communities is one of the most promising ways to treat diseases causes by pathogenic microbes and to counteract the rapid emergence of strains resistant to conventional antibiotics.
Above image: Close-up on wrinkles within a Pseudomonas aeruginosa biofilm.