- A drug used to treat bacterial infections. The original definition of an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another microorganism. However, wholly synthetic antibiotics (usually chemically related to natural antibiotics) have since been produced that accomplish comparable tasks. In 1926, Alexander Fleming discovered penicillin, a substance produced by fungi that appeared able to inhibit bacterial growth. In 1939, Edward Chain and Howard Florey further studied penicillin and later carried out trials of penicillin on humans (with what were deemed fatal bacterial infections). Fleming, Florey and Chain shared the Nobel Prize in 1945 for their work which ushered in the era of antibiotics. Another antibiotic, for example, is tetracycline (brand names: ACHROMYCIN and SUMYCIN), a broad-spectrum agent effective against a wide variety of bacteria including Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Neisseria gonorrhoea, and many others. The first drug of the tetracycline family, chlortetracycline, was introduced in 1948.
* * *1. Relating to antibiosis. 2. Prejudicial to life. 3. A soluble substance derived from a mold or bacterium that inhibits the growth of other microorganisms. 4. Relating to such an action.- broad-spectrum a. an a. having a wide range of activity against both Gram-positive and Gram-negative organisms.- peptide a. a. composed of peptides; the antibacterial action is based on the physical disruption of cell membranes.
* * *1) tending to prevent, inhibit, or destroy life2) of or relating to antibiotics or to antibiosisan·ti·bi·ot·i·cal·ly -i-k(ə-)lē advantibiotic n a substance produced by or a semisynthetic substance derived from a microorganism and able in dilute solution to inhibit or kill another microorganism
* * *n.a substance, produced by or derived from a microorganism, that destroys or inhibits the growth of other microorganisms. Antibiotics are used to treat infections caused by organisms that are sensitive to them, usually bacteria or fungi. They may alter the normal microbial content of the body (e.g. in the intestine, lungs, bladder) by destroying one or more groups of harmless or beneficial organisms, which may result in infections (such as thrush in women) due to over-growth of resistant organisms. These side-effects are most likely to occur with broad-spectrum antibiotics (those active against a wide variety of organisms). Resistance may also develop in the microorganisms being treated; for example, through incorrect dosage or overprescription (see also superinfection). Antibiotics should not be used to treat minor infections, which will clear up unaided. Some antibiotics may cause allergic reactions. See also aminoglycosides, antifungal, antiviral drug, cephalosporin, chloramphenicol, penicillin, quinolone, streptomycin, tetracycline.
* * *an·ti·bi·ot·ic (an″te-) (an″ti-bi-otґik) [anti- + biotic] 1. destructive of life. 2. a chemical substance having the capacity, in dilute solution, to kill or inhibit growth of microorganisms. Antibiotics that are sufficiently nontoxic to the host are used as chemotherapeutic agents to treat infectious diseases. The term was originally restricted to substances produced by microorganisms, but has been extended to include synthetic and semisynthetic compounds of similar chemical activity.
Medical dictionary. 2011.