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Phage therapy or viral phage therapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections.〔 Phage therapy has many potential applications in human medicine as well as dentistry, veterinary science, and agriculture.〔 If the target host of a phage therapy treatment is not an animal the term "biocontrol" (as in phage-mediated biocontrol of bacteria) is usually employed, rather than "phage therapy". Bacteriophages are much more specific than antibiotics, so they can hypothetically be chosen to be indirectly harmless not only to the host organism (human, animal, or plant), but also to other beneficial bacteria, such as gut flora, reducing the chances of opportunistic infections.〔 They would have a high therapeutic index, that is, phage therapy would be expected to give rise to few side effects. Because phages replicate ''in vivo'', a smaller effective dose can be used. On the other hand, this specificity is also a disadvantage: a phage will only kill a bacterium if it is a match to the specific strain. Consequently phage mixtures are often applied to improve the chances of success, or samples can be taken and an appropriate phage identified and grown. Phages are currently being used therapeutically to treat bacterial infections that do not respond to conventional antibiotics, particularly in Russia〔 and Georgia.〔〔〔 There is also a phage therapy unit in Wroclaw, Poland, established 2005, the only such centre in European Union countries.〔http://www.iitd.pan.wroc.pl/en/clinphage2015〕 Phages tend to be more successful than antibiotics where there is a biofilm covered by a polysaccharide layer, which antibiotics typically cannot penetrate.〔 In the West, no therapies are currently authorized for use on humans, although phages for killing food poisoning bacteria (''Listeria'') are now in use.〔 == History == The discovery of bacteriophages was reported by Frederick Twort in 1915 and Felix d'Hérelle〔 in 1917. D'Hérelle said that the phages always appeared in the stools of ''Shigella'' dysentery patients shortly before they began to recover.〔 He "quickly learned that bacteriophages are found wherever bacteria thrive: in sewers, in rivers that catch waste runoff from pipes, and in the stools of convalescent patients."〔 Phage therapy was immediately recognized by many to be a key way forward for the eradication of bacterial infections. A Georgian, George Eliava, was making similar discoveries. He travelled to the Pasteur Institute in Paris where he met d'Hérelle, and in 1923 he founded the Eliava Institute in Tbilisi, Georgia, devoted to the development of phage therapy. In neighbouring countries including Russia, extensive research and development soon began in this field. In the United States during the 1940s commercialization of phage therapy was undertaken by the large pharmaceutical company, Eli Lilly. While knowledge was being accumulated regarding the biology of phages and how to use phage cocktails correctly, early uses of phage therapy were often unreliable.〔 When antibiotics were discovered in 1941 and marketed widely in the U.S. and Europe, Western scientists mostly lost interest in further use and study of phage therapy for some time.〔 Isolated from Western advances in antibiotic production in the 1940s, Russian scientists continued to develop already successful phage therapy to treat the wounds of soldiers in field hospitals. During World War II, the Soviet Union used bacteriophages to treat many soldiers infected with various bacterial diseases e.g. dysentery and gangrene. Russian researchers continued to develop and to refine their treatments and to publish their research and results. However, due to the scientific barriers of the Cold War, this knowledge was not translated and did not proliferate across the world.〔〔 A summary of these publications was published in English in 2009 in "A Literature Review of the Practical Application of Bacteriophage Research" 〔 There is an extensive library and research center at the George Eliava Institute in Tbilisi, Georgia. Phage therapy is today a widespread form of treatment in that region. As a result of the development of antibiotic resistance since the 1950s and an advancement of scientific knowledge, there has been renewed interest worldwide in the ability of phage therapy to eradicate bacterial infections and chronic polymicrobial biofilm (including in industrial situations〔). Phages have been investigated as a potential means to eliminate pathogens like ''Campylobacter'' in raw food〔 and ''Listeria'' in fresh food or to reduce food spoilage bacteria.〔 In agricultural practice phages were used to fight pathogens like ''Campylobacter'', ''Escherichia'' and ''Salmonella'' in farm animals, ''Lactococcus'' and ''Vibrio'' pathogens in fish from aquaculture and ''Erwinia'' and ''Xanthomonas'' in plants of agricultural importance. The oldest use was, however, in human medicine. Phages have been used against diarrheal diseases caused by ''E. coli'', ''Shigella'' or ''Vibrio'' and against wound infections caused by facultative pathogens of the skin like staphylococci and streptococci. Recently the phage therapy approach has been applied to systemic and even intracellular infections and the addition of non-replicating phage and isolated phage enzymes like lysins to the antimicrobial arsenal. However, actual proof for the efficacy of these phage approaches in the field or the hospital is not available.〔 Some of the interest in the West can be traced back to 1994, when Soothill demonstrated (in an animal model) that the use of phages could improve the success of skin grafts by reducing the underlying ''Pseudomonas aeruginosa'' infection.〔 Recent studies have provided additional support for these findings in the model system.〔 Although not "phage therapy" in the original sense, the use of phages as delivery mechanisms for traditional antibiotics constitutes another possible therapeutic use.〔〔 The use of phages to deliver antitumor agents has also been described in preliminary ''in vitro'' experiments for cells in tissue culture.〔 In June 2015 the European Medicines Agency hosted a one day workshop on the therapeutic use of bacteriophages〔http://www.ema.europa.eu/ema/index.jsp?curl=pages/news_and_events/events/2015/05/event_detail_001155.jsp&mid=WC0b01ac058004d5c3〕 and in July 2015 the National Institutes of Health (USA)hosted a two day workshop "Bacteriophage Therapy: An Alternative Strategy to Combat Drug Resistance".〔https://respond.niaid.nih.gov/conferences/bacteriophage/Pages/Agenda.aspx〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「phage therapy」の詳細全文を読む スポンサード リンク
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