gramicidin

1. Pertaining to the ability to destroy or inhibit other living organisms.

2. A substance derived from a mould or bacterium, or produced synthetically, that destroys (bactericidal) or inhibits the growth (bacteriostatic) of other microorganisms and is thus used to treat infections. Some substances have a narrow spectrum of activity whereas others act against a wide range of both gram-positive and gram-negative organisms (broad-spectrum antibiotics). Antibiotics can be classified into several groups according to their mode of action on or within bacteria: (1) Drugs inhibiting bacterial cell wall synthesis, such as bacitracin, vancomycin and the β-lactams based agents (e.g. penicillin, cephalosporins (e.g. ceftazidime, ceftriaxone, cefuroxime). (2) Drugs affecting the bacterial cytoplasmic membrane, such as polymyxin B sulfate and gramicidin. (3) Drugs inhibiting bacterial protein synthesis, such as aminoglycosides (e.g. amikacin sulfate, framycetin sulfate, gentamicin, neomycin sulfate and tobramycin), tetracyclines, macrolides (e.g. erythromycin and azithromycin) and chloramphenicol. (4) Drugs inhibiting the intermediate metabolism of bacteria, such as sulfonamides (e.g. sulfacetamide sodium) and trimethoprim. (5) Drugs inhibiting bacterial DNA synthesis, such as nalixidic acid and fluoroquinolones (e.g. ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin and ofloxacin). (6) Other antibiotics such as fusidic acid, the diamidines, such as propamidine isethionate and dibrompropamidine. Syn. antibacterial. See antiinflammatory drug; fusidic acid.