Antibiotic resistant bacteria in terrestrial and aquatic environments: A review

Antibiotic resistant bacteria have become increasingly widespread in the environment and their prevalence is a serious potential problem for human health. The rise and spread of this resistance is primarily due to the overuse of antibiotics in clinical therapeutics and as growth promoters for livestock. Overuse undermines the usefulness of antibiotics by giving a selective advantage to microbes that are resistant. The problem has been exacerbated by the emergence of bacteria that are resistant to multiple antibiotics and by the ability of these resistance determinants to spread between different bacteria via horizontal gene transfer. Such transfer can, for example, take place extensively in the digestive tract of domestic animals and aquatic environments, which can become reservoirs of multiple antibiotic resistant bacteria (MARB) and these sources contribute eventually to spread of antibiotic resistance to humans.