Textbook Problem

Antibiotics enter the environment in wastewater from pharmaceutical manufacturing plants, in wastes from farms where they are used in animals, and in sewage from human populations. (Many antibiotics are excreted in their active form.) The influx of antibiotics into the environment is a concern because the presence of these compounds in the environment selects for antibiotic resistance. As pollutants, antibiotics can also have ecological effects. Describe some of the ecological roles of bacteria, and explain why disruption of these roles by antibiotic pollution would have a negative impact.