date:Jan 07, 2013
through evolutionary pressure. Every time an antibiotic is used bacteria evolves and thus its efficacy may diminish. Commercially antibiotics were used in animals for disease control.
During the 1960s, the use of antibiotics for growth promotion for weight increase in animals grew substantially. Antibiotics commonly used in humans like penicillin and tetracycline were increasingly used for feed efficiency and weight gain. There is increasing evidence of the development of antibiotic-resistant