Pharmaceuticals roles in microbial evolution

Abstract Environmental microorganisms consist of a large unexplored reservoir of genetic diversity, which plays a key role in fundamental processes. Frequent disposal of wastewater (industrial, domestic, and hospital) causes a widespread contamination in various ecosystems. Pharmaceuticals have been detected in various environments, but their effects on microbial evolution and ecology have been poorly investigated. Pharmaceuticals present in marine, soil, and freshwater environment have been discussed with examples in this chapter. Antibiotics have some natural functions (e.g., cell–cell signaling), and the anthropogenic production of antibiotics results in disturbance, tending the resistance to preserve its integrity. It not only compromises the microbial community structure and activities but also build a selective pressure of a particular trait (e.g., antibiotic resistance), resulting in their emergence and dissemination. The antibiotic resistance can be acquired or natural and the acquired resistance evolve by mutations in the genome or acquisition of resistance genes by horizontal gene transfer. Microbial evolution in different environments due to pharmaceuticals has been explained in this chapter.