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 gastric juices and hydrogen peroxide). It also excluded synthetic antibacterial compounds such as the sulfonamides. In current usage, the term "antibiotic" is applied to any medication that kills bacteria or inhibits their growth, regardless of whether that medication is produced by a microorganism or not. The term "antibiotic" derives from "anti" + βιωτικός ("biōtikos"), "fit for life, lively", which comes from βίωσις ("biōsis"), "way of life", and that from βίος ("bios"), "life". The term "antibacterial" derives from Greek ἀντί ("anti"), "against" + βακτήριον ("baktērion"), diminutive of βακτηρία ("baktēria"), "staff, cane", because the first bacteria to be discovered were rod-shaped. The