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
Dental antibiotic prophylaxis conditions for which clinicians recommended antibiotic prophylaxis, although there is no evidence to support this practice. These conditions include renal dialysis shunt, cerebrospinal fluid shunt, vascular graft, immunosuppression secondary to cancer and cancer chemotherapy, systemic lupus erythematosus, and type 1 diabetes mellitus. It is of importance to dental patients and practitioners to remain current with regards to the latest recommendations rendered by professional governing bodies such as the American Dental Association (ADA), American Heart Association (AHA) and the American Association of Orthopaedic surgeons (AAOS). Antibiotic prophylaxis is intended to avoid adverse outcomes in certain patients at "highest risk of postoperative