penicillin

penicillin,

any of a group of chemically similar substances obtained from molds of the genus Penicillium that were the first antibioticantibiotic,
any of a variety of substances, usually obtained from microorganisms, that inhibit the growth of or destroy certain other microorganisms. Types of Antibiotics
..... Click the link for more information. agents to be used successfully in the treatment of bacterial infections in humans. The antagonistic effect of penicillin on bacteria was first observed by the Scottish biologist Sir Alexander FlemingFleming, Sir Alexander,
1881–1955, Scottish bacteriologist, discoverer of penicillin (1928) and lysozyme (1922), an antibacterial substance found in saliva and other body secretions. Educated at St. Mary's Hospital Medical School, Univ.
..... Click the link for more information. in 1928. Although he recognized the therapeutic potential of penicillin, it was not until 1941 that a group of biologists working in England, including Oxford's Sir H. W. FloreyFlorey, Howard Walter Florey, Baron,
1898–1968, British pathologist, b. Australia. He was educated at Adelaide Univ. and at Cambridge and Oxford and returned to Oxford as professor of pathology in 1935.
..... Click the link for more information. and E. B. ChainChain, Ernst Boris,
1906–79, English biochemist, b. Berlin, Germany. In 1933 he left Germany and went to England, where he conducted research at Cambridge from 1933 to 1935 and at Oxford from 1935; he lectured (1936–48) in chemical pathology at Oxford.
..... Click the link for more information. , purified the substance and established its effectiveness against infectious organisms and its lack of toxicity to humans. The first successful treatment of a patient with penicillin occurred in New Haven, Conn., in 1942. Despite the development of hundreds of different antibiotics in recent decades, penicillin remains important in antibiotic therapy.

Small amounts of the antibiotic were first obtained from strains of the mold species P. notatum grown in fermentation bottles. During World War II need for the drug spurred development of better production methods; in the current method highly productive strains of Penicillium are grown in a cornsteep liquor medium in fermentation vats. The main form of penicillin produced by this method is benzylpenicillin, which, like all penicillins, is a derivative of 6-aminopenicillanic acid. Phenoxymethyl penicillin, which can be given orally because it is resistant to degradation by stomach acid, is produced by the species P. chrysogenum.

Effectiveness

Penicillin is effective against many gram-positive bacteria (see Gram's stainGram's stain,
laboratory staining technique that distinguishes between two groups of bacteria by the identification of differences in the structure of their cell walls. The Gram stain, named after its developer, Danish bacteriologist Christian Gram, has become an important tool
..... Click the link for more information. ), including those that cause syphilis, meningococcal meningitis, gas gangrene, pneumococcal pneumonia, and some staphylococcal and streptococcal infections. Most gram-negative bacteria are resistant to the antibiotic, but some, such as the bacteria that cause gonorrhea, are susceptible, and others are responsive to high penicillin concentrations or to only certain classes of penicillins. Tuberculosis bacteria, protozoans, viruses, and most fungi are not affected by penicillin. The class of penicillins that includes ampicillinampicillin
, a penicillin-type antibiotic that is effective against both gram-negative microorganisms and gram-positive microorganisms such as Escherichia coli. It is often used in the treatment of urinary tract infections, but resistant organisms are increasingly common
..... Click the link for more information. and amoxicillin with clavulanate (Augmentin) is active against gram-positive and gram-negative bacteria such as Haemophilus influenzae and Escherichia coli. All penicillins act by interfering with synthesis of the cell wall.

Drug Resistance and Sensitivity

Use of penicillin is limited by the fact that, although it causes fewer side effects than many other antibiotics, it causes allergic sensitivity in many individuals, including skin reactions and allergic shock. In addition, many microorganisms have developed resistance to the penicillins, and serious hospital epidemics involving infants and surgical patients have been caused by penicillin-resistant staphylococci (see drug resistancedrug resistance,
condition in which infecting bacteria can resist the destructive effects of drugs such as antibiotics and sulfa drugs. Drug resistance has become a serious public health problem, since many disease-causing bacteria are no longer susceptible to previously
..... Click the link for more information. ). Some organisms are resistant because they produce an enzyme, penicillinase, that destroys the antibiotic. Synthetically produced penicillins such as methicillin and oxacillin have been developed that are not degraded by the penicillinase enzyme, but these new penicillins have no effect on bacteria that have developed resistance by other means, e.g., by altered cell wall structure. Other antibiotics, such as erythromycinerythromycin
, any of several related antibiotic drugs produced by bacteria of the genus Streptomyces (see antibiotic). Erythromycin is most effective against gram-positive bacteria such as pneumococci, streptococci, and some staphylococci (see Gram's stain).
..... Click the link for more information. , have become important in treating infections by microorganisms resistant to penicillin.

Bibliography

See E. Lax, The Mold in Dr. Florey's Coat: The Story of the Penicillin Miracle (2004).

penicillin

[‚pen·ə′sil·ən] (microbiology) The collective name for salts of a series of antibiotic organic acids produced by a number of Penicillium and Aspergillus species; active against most gram-positive bacteria and some gram-negative cocci. benzyl penicillin sodium

penicillin

any of a group of antibiotics with powerful bactericidal action, used to treat many types of infections, including pneumonia, gonorrhoea, and infections caused by streptococci and staphylococci: originally obtained from the fungus Penicillium, esp P. notatum. Formula: R-C₉H₁₁N₂O₄S where R is one of several side chains

penicillin

[pen″ĭ-sil´in] any of a large group of natural or semisynthetic antibacterial antibiotics derived directly or indirectly from strains of fungi of the genus Penicillium and other soil-inhabiting fungi grown on special culture media. Penicillins exert a bacteriocidal as well as a bacteriostatic effect on susceptible bacteria by interfering with the final stages of the synthesis of peptidoglycan, a substance in the bacterial cell wall. Despite their relatively low toxicity for the host, they are active against many bacteria, especially gram-positive pathogens (streptococci, staphylococci, pneumococci); clostridia; certain gram-negative forms (gonococci and meningococci); certain spirochetes (Treponema pallidum and T. pertenue); and certain fungi. Certain strains of some target species, for example staphylococci, secrete the enzyme penicillinase, which inactivates penicillin and confers resistance to the antibiotic. Some of the newer penicillins, such as methicillin, are more effective against penicillinase-producing organisms. A class of extended-spectrum penicillins includes piperacillin and mezlocillin.
Penicillin is administered intramuscularly, orally, in liquid or tablet form, and topically in ointments. Oral administration requires larger doses of the drug because absorption is incomplete. Allergic reactions occur in some persons. The reaction may be slight—a stinging or burning sensation at the site of injection—or it can be more serious—severe dermatitis or even anaphylactic shock, which may be fatal.penicillin G the most widely used penicillin, used principally in the treatment of infections due to gram-positive organisms, gram-negative cocci, Treponema pallidum and Actinomyces israelii. The usual forms are salts such as penicillin benzathine, potassium, procaine, or sodium. Called also benzylpenicillin.penicillin V a biosynthetically or semisynthetically produced antibiotic similar to penicillin g, used orally in the form of the benzathine or potassium salt for mild to moderately severe infections due to susceptible gram-positive bacteria.

pen·i·cil·lin

(pen'i-sil'in), 1. Originally, an antibiotic substance obtained from cultures of the molds Penicillium notatum or P. chrysogenum; interferes with cell wall synthesis in bacteria. 2. One of a family of natural or synthetic variants of penicillic acid. They are mainly bactericidal, are especially active against gram-positive organisms, and, with the exception of hypersensitivity reactions, show a particularly low toxic action on animal tissue. [see penicillus]

penicillin

(pĕn′ĭ-sĭl′ĭn)n.1. An antibiotic drug obtained from molds especially of the genus Penicillium or produced synthetically, available in various preparations and usually used to treat infections caused by gram-positive bacteria.2. Any of a group of broad-spectrum antibiotic drugs, synthetic or semisynthetic, that are derived from penicillin.

penicillin

Infectious disease An antibiotic that inhibits crosslinking of peptidoglycan chains in bacterial cell walls; bacteria growing in penicillin synthesize weak cell walls, causing them to burst due to the high osmotic pressure. See Ampicillin.

pen·i·cil·lin

(pen'i-sil'in) 1. Originally, an antibiotic substance obtained from cultures of the molds Penicillium notatum or P. chrysogenum; interferes with cell wall synthesis in bacteria. 2. One of a family of natural or synthetic variants of penicillic acid. They are mainly bactericidal, are especially active against gram-positive organisms, and, with the exception of hypersensitivity reactions, show a particularly low toxic action on animal tissue.

penicillin

an antibiotic produced by the FUNGUS Penicillium that is toxic to a number of bacteria, both pathogenic and nonpathogenic. In 1928 it was observed by Sir Alexander FLEMING that the FUNGUS inhibited growth of bacteria, and that a substance extracted from it still had this antibiotic property

antibiotic

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.

pen·i·cil·lin

(pen'i-sil'in) One of a family of natural or synthetic variants of penicillic acid; mainly bactericidal, are especially active against gram-positive organisms, and, with the exception of hypersensitivity reactions, show a particularly low toxic action on animal tissue.

Patient discussion about penicillin

Q. is it possible to drink alcohol during taking penicillin antibiotic? A. i know that it's probably bad to take antibiotics with alcohol but couldn't remember why. so i looked you question up until i found a Doctor's answer to it-
http://medical.justanswer.com/dentist/1c5dz-okay-drink-alcohol-penicillin

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Effectiveness

Drug Resistance and Sensitivity

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Words related to penicillin

noun any of various antibiotics obtained from Penicillium molds (or produced synthetically) and used in the treatment of various infections and diseases

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