International Journal of Antimicrobial Agents. Testing the susceptibility of Staphylococcus aureus to antibiotics by the Kirby-Bauer disk diffusion method — antibiotics diffuse from antibiotic-containing disks and inhibit growth of S. International Journal of Obesity. PHLX bietet ein Retrieved 28 December
BREAKING DOWN 'Deutscher Aktienindex 100 - DAX 100'
German stock market indices Companies listed on the Frankfurt Stock Exchange. Webarchive template wayback links All articles with dead external links Articles with dead external links from September Articles with permanently dead external links Use dmy dates from November Pages using deprecated image syntax. Views Read Edit View history.
DAX performance between and Merged with Siemens to form Siemens-Nixdorf. Continental was added back to the DAX on 22 September , though it was demoted again in and added back again in Merger of Thyssen and Krupp.
Merger of Hoechst and Rhône-Poulenc with Aventis. Fast-exit of Epcos, as Epcos' market capitalisation became inadequate. Lanxess was spun off from Bayer. It was added to the DAX in and removed in After the sale of Nycomed , inadequate market capitalisation . Fast-exit of Continental because of inadequate free-float market capitalisation after the acquisition by Schaeffler Group. Some systemic absorption of the antibiotic may occur; the quantity of antibiotic applied is difficult to accurately dose, and there is also the possibility of local hypersensitivity reactions or contact dermatitis occurring.
Antibiotics are screened for any negative effects before their approval for clinical use, and are usually considered safe and well tolerated.
However, some antibiotics have been associated with a wide extent of adverse side effects ranging from mild to very severe depending on the type of antibiotic used, the microbes targeted, and the individual patient. Common side-effects include diarrhea , resulting from disruption of the species composition in the intestinal flora , resulting, for example, in overgrowth of pathogenic bacteria, such as Clostridium difficile.
Exposure to antibiotics early in life is associated with increased body mass in humans and mouse models. Although there is a correlation between antibiotic use in early life and obesity, the effect of antibiotics on obesity in humans needs to be weighed against the beneficial effects of clinically indicated treatment with antibiotics in infancy.
There are few well controlled studies on whether antibiotic use increases the risk of oral contraceptive failure. Gastrointestinal disorders or interpatient variability in oral contraceptive absorption affecting ethinylestradiol serum levels in the blood. If patient-specific risk factors for reduced oral contraceptive efficacy are suspected, backup contraception is recommended.
In cases where antibiotics have been suggested to affect the efficiency of birth control pills, such as for the broad-spectrum antibiotic rifampicin , these cases may be due to an increase in the activities of hepatic liver enzymes' causing increased breakdown of the pill's active ingredients. Interactions between alcohol and certain antibiotics may occur and may cause side-effects and decreased effectiveness of antibiotic therapy.
Antibiotics such as metronidazole , tinidazole , cephamandole , latamoxef , cefoperazone , cefmenoxime , and furazolidone , cause a disulfiram -like chemical reaction with alcohol by inhibiting its breakdown by acetaldehyde dehydrogenase , which may result in vomiting, nausea, and shortness of breath.
The successful outcome of antimicrobial therapy with antibacterial compounds depends on several factors. These include host defense mechanisms , the location of infection, and the pharmacokinetic and pharmacodynamic properties of the antibacterial. In important infectious diseases, including tuberculosis, combination therapy i.
In acute bacterial infections, antibiotics as part of combination therapy are prescribed for their synergistic effects to improve treatment outcome as the combined effect of both antibiotics is better than their individual effect. However, this can vary depending on the species of bacteria. Antibiotics are commonly classified based on their mechanism of action , chemical structure , or spectrum of activity. Most target bacterial functions or growth processes.
Protein synthesis inhibitors macrolides , lincosamides , and tetracyclines are usually bacteriostatic with the exception of bactericidal aminoglycosides. Following a year break in discovering new classes of antibacterial compounds, four new classes of antibiotics have been brought into clinical use in the late s and early s: With advances in medicinal chemistry , most modern antibacterials are semisynthetic modifications of various natural compounds.
Compounds that are still isolated from living organisms are the aminoglycosides , whereas other antibacterials—for example, the sulfonamides , the quinolones , and the oxazolidinones —are produced solely by chemical synthesis.
Since the first pioneering efforts of Howard Florey and Chain in , the importance of antibiotics, including antibacterials, to medicine has led to intense research into producing antibacterials at large scales. Following screening of antibacterials against a wide range of bacteria, production of the active compounds is carried out using fermentation , usually in strongly aerobic conditions.
The emergence of resistance of bacteria to antibiotics is a common phenomenon. Emergence of resistance often reflects evolutionary processes that take place during antibiotic therapy.
The antibiotic treatment may select for bacterial strains with physiologically or genetically enhanced capacity to survive high doses of antibiotics. Under certain conditions, it may result in preferential growth of resistant bacteria, while growth of susceptible bacteria is inhibited by the drug. Resistance may take the form of biodegredation of pharmaceuticals, such as sulfamethazine-degrading soil bacteria introduced to sulfamethazine through medicated pig feces.
Horizontal transfer is more likely to happen in locations of frequent antibiotic use. Antibacterial resistance may impose a biological cost, thereby reducing fitness of resistant strains, which can limit the spread of antibacterial-resistant bacteria, for example, in the absence of antibacterial compounds. Additional mutations, however, may compensate for this fitness cost and can aid the survival of these bacteria. Paleontological data show that both antibiotics and antibiotic resistance are ancient compounds and mechanisms.
Several molecular mechanisms of antibacterial resistance exist. Intrinsic antibacterial resistance may be part of the genetic makeup of bacterial strains. Acquired resistance results from a mutation in the bacterial chromosome or the acquisition of extra-chromosomal DNA. Antibacterial-resistant strains and species, sometimes referred to as "superbugs", now contribute to the emergence of diseases that were for a while well controlled.
For example, emergent bacterial strains causing tuberculosis that are resistant to previously effective antibacterial treatments pose many therapeutic challenges. Every year, nearly half a million new cases of multidrug-resistant tuberculosis MDR-TB are estimated to occur worldwide. Per The ICU Book "The first rule of antibiotics is try not to use them, and the second rule is try not to use too many of them. Self-prescribing of antibiotics is an example of misuse.
Also, incorrect or suboptimal antibiotics are prescribed for certain bacterial infections. Common forms of antibiotic misuse include excessive use of prophylactic antibiotics in travelers and failure of medical professionals to prescribe the correct dosage of antibiotics on the basis of the patient's weight and history of prior use. Other forms of misuse include failure to take the entire prescribed course of the antibiotic, incorrect dosage and administration, or failure to rest for sufficient recovery.
Inappropriate antibiotic treatment, for example, is their prescription to treat viral infections such as the common cold. One study on respiratory tract infections found "physicians were more likely to prescribe antibiotics to patients who appeared to expect them". Several organizations concerned with antimicrobial resistance are lobbying to eliminate the unnecessary use of antibiotics. The emergence of antibiotic resistance has prompted restrictions on their use in the UK in Swann report , and the EU has banned the use of antibiotics as growth-promotional agents since Food and Drug Administration have advocated restricting the amount of antibiotic use in food animal production.
Two federal bills S. Despite pledges by food companies and restaurants to reduce or eliminate meat that comes from animals treated with antibiotics, the purchase of antibiotics for use on farm animals has been increasing every year. There has been extensive use of antibiotics in animal husbandry. In the United States, the question of emergence of antibiotic-resistant bacterial strains due to use of antibiotics in livestock was raised by the US Food and Drug Administration FDA in Before the early 20th century, treatments for infections were based primarily on medicinal folklore.
Mixtures with antimicrobial properties that were used in treatments of infections were described over years ago. The use of antibiotics in modern medicine began with the discovery of synthetic antibiotics derived from dyes.
Synthetic antibiotic chemotherapy as a science and development of antibacterials began in Germany with Paul Ehrlich in the late s. He then proposed the idea that it might be possible to create chemicals that would act as a selective drug that would bind to and kill bacteria without harming the human host. After screening hundreds of dyes against various organisms, in , he discovered a medicinally useful drug, the first synthetic antibacterial salvarsan    now called arsphenamine.
The era of antibacterial treatment began with the discoveries of arsenic-derived synthetic antibiotics by Alfred Bertheim and Ehrlich in While their early compounds were too toxic, Ehrlich and Sahachiro Hata , a Japanese bacteriologist working with Erlich in the quest for a drug to treat syphilis , achieved success with the th compound in their series of experiments.
In Ehrlich and Hata announced their discovery, which they called drug "", at the Congress for Internal Medicine at Wiesbaden.
This drug is now known as arsphenamine. In , Ehrlich received the Nobel Prize in Physiology or Medicine for his contributions to immunology. The first sulfonamide and the first systemically active antibacterial drug, Prontosil , was developed by a research team led by Gerhard Domagk in or at the Bayer Laboratories of the IG Farben conglomerate in Germany,    for which Domagk received the Nobel Prize in Physiology or Medicine.
Research was stimulated apace by its success. The discovery and development of this sulfonamide drug opened the era of antibacterials. Observations about the growth of some microorganisms inhibiting the growth of other microorganisms have been reported since the late 19th century.
These observations of antibiosis between microorganisms led to the discovery of natural antibacterials. Louis Pasteur observed, "if we could intervene in the antagonism observed between some bacteria, it would offer perhaps the greatest hopes for therapeutics". In , physician Sir William Roberts noted that cultures of the mold Penicillium glaucum that is used in the making of some types of blue cheese did not display bacterial contamination.
In Vincenzo Tiberio , Italian physician, published a paper on the antibacterial power of some extracts of mold. In , doctoral student Ernest Duchesne submitted a dissertation, "Contribution à l'étude de la concurrence vitale chez les micro-organismes: In his thesis, Duchesne proposed that bacteria and molds engage in a perpetual battle for survival.
Duchesne observed that E. He also observed that when he inoculated laboratory animals with lethal doses of typhoid bacilli together with Penicillium glaucum , the animals did not contract typhoid. Unfortunately Duchesne's army service after getting his degree prevented him from doing any further research.
In , Sir Alexander Fleming postulated the existence of penicillin , a molecule produced by certain molds that kills or stops the growth of certain kinds of bacteria. Fleming was working on a culture of disease-causing bacteria when he noticed the spores of a green mold, Penicillium chrysogenum , in one of his culture plates.
He observed that the presence of the mold killed or prevented the growth of the bacteria. Fleming believed that its antibacterial properties could be exploited for chemotherapy.
He initially characterized some of its biological properties, and attempted to use a crude preparation to treat some infections, but he was unable to pursue its further development without the aid of trained chemists.
Ernst Chain , Howard Florey and Edward Abraham succeeded in purifying the first penicillin, penicillin G , in , but it did not become widely available outside the Allied military before Later, Norman Heatley developed the back extraction technique for efficiently purifying penicillin in bulk.
The chemical structure of penicillin was first proposed by Abraham in  and then later confirmed by Dorothy Crowfoot Hodgkin in Purified penicillin displayed potent antibacterial activity against a wide range of bacteria and had low toxicity in humans.
Furthermore, its activity was not inhibited by biological constituents such as pus, unlike the synthetic sulfonamides. Florey credited Rene Dubos with pioneering the approach of deliberately and systematically searching for antibacterial compounds, which had led to the discovery of gramicidin and had revived Florey's research in penicillin. It was one of the first commercially manufactured antibiotics and was very effective in treating wounds and ulcers during World War II.
Tyrocidine also proved too toxic for systemic usage. Research results obtained during that period were not shared between the Axis and the Allied powers during World War II and limited access during the Cold War.
The term 'antibiosis', meaning "against life", was introduced by the French bacteriologist Jean Paul Vuillemin as a descriptive name of the phenomenon exhibited by these early antibacterial drugs.
The term antibiotic was first used in by Selman Waksman and his collaborators in journal articles to describe any substance produced by a microorganism that is antagonistic to the growth of other microorganisms in high dilution.
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 increase in bacterial strains that are resistant to conventional antibacterial therapies together with decreasing number of new antibiotics currently being developed in the drug pipeline has prompted the development of bacterial disease treatment strategies that are alternatives to conventional antibacterials.
One strategy to address bacterial drug resistance is the discovery and application of compounds that modify resistance to common antibacterials. Resistance modifying agents are capable of partly or completely suppressing bacterial resistance mechanisms. Metabolic stimuli such as sugar can help eradicate a certain type of antibiotic-tolerant bacteria by keeping their metabolism active.
Vaccines rely on immune modulation or augmentation. Vaccination either excites or reinforces the immune competence of a host to ward off infection, leading to the activation of macrophages , the production of antibodies , inflammation , and other classic immune reactions. Antibacterial vaccines have been responsible for a drastic reduction in global bacterial diseases. Phage therapy is another method for treating antibiotic-resistant strains of bacteria. Phage therapy infects pathogenic bacteria with their own viruses.
Bacteriophages and their host ranges are extremely specific for certain bacteria, thus they do not disturb the host organism and intestinal microflora unlike antibiotics. However, some disadvantages to use of bacteriophages also exist. Bacteriophages may harbour virulence factors or toxic genes in their genomes and identification of genes with similarity to known virulence factors or toxins by genomic sequencing may be prudent prior to use.
In addition, the oral and IV administration of phages for the eradication of bacterial infections poses a much higher safety risk than topical application, and there is the additional concern of uncertain immune responses to these large antigenic cocktails.
There are considerable regulatory hurdles that must be cleared for such therapies. Plants are an important source of antimicrobial compounds and traditional healers have long used plants to prevent or cure infectious diseases. These drugs however, did not address the entire spectrum of resistance of GNB.
Recent entries in the clinical pipeline targeting multidrug-resistant Gram-positive pathogens has improved the treatment options due to marketing approval of new antibiotic classes, the oxazolidinones and cyclic lipopeptides. However, resistance to these antibiotics is certainly likely to occur, the need for the development new antibiotics against those pathogens still remains a high priority.
A few antibiotics have received marketing authorization in the last seven years. The cephalosporin ceftaroline and the lipoglycopeptides oritavancin and telavancin for the treatment of acute bacterial skin and skin structure infection and community-acquired bacterial pneumonia.
The first in a new class of narrow spectrum macrocyclic antibiotics, fidaxomicin, has been approved for the treatment of C. Streptomyces research is expected to provide new antibiotics, including treatment against MRSA and infections resistant to commonly used medication. Possible improvements include clarification of clinical trial regulations by FDA.
Furthermore, appropriate economic incentives could persuade pharmaceutical companies to invest in this endeavor. Under this Act, FDA can approve antibiotics and antifungals treating life-threatening infections based on smaller clinical trials. The CDC will monitor the use of antibiotics and the emerging resistance, and publish the data.
The FDA antibiotics labeling process, 'Susceptibility Test Interpretive Criteria for Microbial Organisms' or 'breakpoints', will provide accurate data to healthcare professionals.
From Wikipedia, the free encyclopedia. For non-antibiotic antibacterials, see Antibacterial disambiguation. This article is about treatment of bacterial infection. Testing the susceptibility of Staphylococcus aureus to antibiotics by the Kirby-Bauer disk diffusion method — antibiotics diffuse from antibiotic-containing disks and inhibit growth of S.
This section needs to be updated. Please update this article to reflect recent events or newly available information. This section needs more medical references for verification or relies too heavily on primary sources. Please review the contents of the section and add the appropriate references if you can. Unsourced or poorly sourced material may be challenged and removed.
FDA approved on 19 December Aminoglycoside protein synthesis inhibitor. Development by Tetraphase, Phase 2 trials complete. Peptide defense protein mimetic cell membrane disruption. Retrieved 17 January European Centre for Disease Prevention and Control.
Retrieved 21 December