Broad-spectrum antibiotic their greater potential to disrupt a larger variety of normal human flora. After continued exposure to an antibiotic, bacteria may develop changes in their structure or function that make them resistant to the antibiotic. These resistant organisms will live, while the susceptible organisms will die, leaving the population of bacteria entirely resistant to a given antibiotics. For example, after the discovery of penicillin and its subsequent use to treat bacterial infections, bacteria were found to have begun producing an enzyme, penicillinase, which rendered the penicillin molecule inactive. In response to this newly-acquired resistance, newer penicillins were produced that could not
Antibiotic use in livestock With further research it is highly likely that a cost effective and health effective alternative could and will be found. Antibiotic use in livestock Antibiotic use in livestock is the use of antibiotics for any purpose in the husbandry of livestock, which includes treatment when ill (therapeutic), treatment of a batch of animals when at least one is diagnosed as ill (metaphylaxis, similar to the way bacterial meningitis is treated in children), and preventative treatment (prophylaxis). The use of subtherapeutic doses in animal feed and water to promote growth and improve feed efficiency is discouraged by the FDA as part