ストレプトマイシン

解説

Streptomyces griseusが産生するアミノ配糖体抗生物質．ペニシリンについで臨床応用された第2番目の抗生物質．硫酸塩は白色から淡黄白色の粉末．硫酸塩は分解点約230 ℃．[α]²⁰_D－79.5°(水)．28 ℃ で水に20 mg mL－1 以上，メタノールに0.85 mg mL－1 溶ける．

生物学のな役割

ペニシリンが効かないグラム陰性菌と結核菌に強い阻止活性をもつため，よく使用された．現在の結核治療は多剤を使用するが，ストレプトマイシンは第一選択薬の一つとして筋肉注射で使われる．細菌のリボソームの30Sおよび50Sの両サブユニットに結合して，タンパク質合成を阻害する．

効能

抗生物質, 抗結核薬, タンパク質合成阻害薬

毒性

LD50 600～1250 mg/kg(マウス，皮下注)

説明

The antibiotic streptomycin is an important and effective chemical for the management of bacterial diseases of fruit trees (especially apple), woody ornamentals, and vegetables. Streptomycin was initially discovered in 1944 and was one of the first antibiotics to be utilized in clinical medicine to control human diseases, and is still important as a feed amendment for growth promotion in agricultural animals. The widespread and diverse usage of streptomycin has contributed to the currently observed global streptomycin resistance (SmR) problem. This problem is especially critical in plant disease management, as there are few alternatives to streptomycin available and, as a consequence of increased usage, SmR has been increasingly observed among bacterial plant pathogens.

化学的特性

Crystalline Powder

来歴

Streptomycin is discovered in 1944 of streptomycin drew immediate interest because it was the least toxic of the broad-spectrum antibiotics known at that time. Indeed, streptomycin was used to treat many gram-negative microbial infections, but because of the ease with which organisms developed resistance to it during treatment, many of these applications were abandoned when the tetracyclines, discussed later, became available. Streptomycin was the first parenterally administered antibiotic active against many microorganisms, but during the last several years, its use has been limited essentially to three situations: (1) the initial treatment of serious tuberculous infections, when the principal drugs of choice (isoniazid, rifampin) cannot be used because of their adverse effects on a particular patient; (2) treatment of enterococcal and other infections, in which synergism between a penicillin and an aminoglycoside is desired; and (3) treatment of certain uncommon infections (plague and tularemia).

使用

Control of bacterial shot-hole, bacterial rots, bacterial canker, bacterial wilts, fire blight, and other diseases caused by gram-positive species of bacteria in pome fruit, stone fruit, citrus fruit, olives, vegetables, potatoes, tobacco, cotton, and ornamentals. Chlorosis may occur on grapes, pears, peaches, and some ornamentals. Formulation types WP; Liquid. Incompatible with pyrethrins and alkaline materials. A mixture of streptomycin and oxytetracycline is highly effective for the control of bacterial canker of peach, citrus canker, soft rot of vegetables, and various other bacterial diseases. Selected tradenames “Agrimycin 17” (sesquisulfate); “AS-50” (sesquisulfate).

定義

ChEBI: A amino cyclitol glycoside that consists of streptidine having a disaccharyl moiety attached at the 4-position. The parent of the streptomycin class

適応症

Streptomycin, an aminoglycoside antibiotic was the first drug shown to reduce tuberculosis mortality. Streptomycin is bactericidal against M. tuberculosis in vitro but is inactive against intracellular organisms. Most M. tuberculosis strains and nontuberculosis species, such as M. kansasii and M. aviumintracellulare, are sensitive. Spontaneous resistance to streptomycin, seen in approximately 1 in 106 tubercle bacilli, is related to a point mutation that involves the gene (rpsl or rrs) that encodes for ribosomal proteins and binding sites.About 80% of strains that are resistant to isoniazid and rifampin are also resistant to streptomycin.

世界保健機関（WHO）

Oral preparations of streptomycin, an aminoglycoside antibiotic isolated from streptomyces griseus in 1944, were formerly widely used to treat intestinal infections. There is no evidence that streptomycin is effective in this indication and its widespread use promotes the emergence of resistant strains of bacteria. The World Health Organization recommends that streptomycin should not be used for the treatment of diarrhoea. (Reference: (WHORUD) The Rational Use of Drugs, , , 1990)

抗菌性

It is less active than gentamicin group compounds against most micro-organisms within the spectrum,but it is particularly active against mycobacteria, including M. kansasii and most strains of M. ulcerans. Brucella (MIC 0.5 mg/L), Francisella, Pasteurella spp. and Yersinia pestis are susceptible.
It is actively bactericidal, the speed of killing increasing progressively with concentration. The antibacterial activity is greatest in a slightly alkaline medium (pH 7.8) and is considerably reduced below pH 6.0. It is so sensitive to the effect of pH that the natural acidity of a solution of streptomycin sulfate may be sufficient to depress its antibacterial activity.

危険性

Damage to nerves and kidneys may result from ingestion. Use restricted by FDA.

作用機序

The mechanism of action of STM and the aminoglycosides in general has not been fully elucidated. It is known that the STM inhibits protein synthesis, but additional effects on misreading of an mRNA template and membrane damage may contribute to the bactericidal action of ST M. Streptomycin is able to diffuse across the outer membrane of Mycobacterium tuberculosis and, ultimately, to penetrate the cytoplasmic membrane through an electrondependent process. Through studies regarding the mechanism of drug resistance, it has been proposed that STM induces a misreading of the genetic code and, thus, inhibits translational initiation. In ST M-resistant organisms, two changes have been discovered: First, S12 protein undergoes a change in which the lysine present at amino acids 43 and 88 in ribosomal protein S12 is replaced with arginine or threonine, and second, the pseudoknot conformation of 16S rRNA, which results from intramolecular base pairing between GCC bases in regions 524 to 526 of the rRNA to CGG bases in regions 505 to 507, is perturbed. It is thought that S12 protein stabilizes the pseudoknot, which is essential for 16S rRNA function. By some yet-to-be-defined mechanism, STM interferes with one or both of the normal actions of the 16S protein and 16S rRNA.

薬理学

Ototoxicity and nephrotoxicity are the major concerns during administration of streptomycin and other aminoglycosides. The toxic effects are dose related and increase with age and underlying renal insufficiency.All aminoglycosides require dose adjustment in renal failure patients. Ototoxicity is severe when aminoglycosides are combined with other potentially ototoxic agents.

臨床応用

Tuberculosis (in combination with other antituberculosis drugs) Infections caused by M. kansasii (in combination with other antimycobacterial agents)
Plague and tularemia, including tularemia pneumonia Bacterial endocarditis (in combination with a penicillin) Brucellosis
Whipple’s disease (in combination with other antibiotics)
The most important use of streptomycin is in the treatment of tuberculosis . Depression of vestibular function by streptomycin has been used in the treatment of patients suffering from Ménière’s disease.

安全性プロファイル

Poison by intravenous and subcutaneous routes. Moderately toxic by ingestion and intraperitoneal routes. An experimental teratogen. Human systemic effects by ingestion and intraperitoneal routes: change in vestibular functions, blood pressure decrease, eosinophilia, respiratory depression, and pulmonary changes. Human reproductive and teratogenic effects by unspecified routes: developmental abnormalities of the eye and ear and effects on newborn including postnatal measures or effects. Toxic to hdneys and central nervous system. Has been implicated in aplastic anemia. Experimental reproductive effects. Human mutation data reported. When heated to decomposition it emits toxic fumes of NOX.

代謝

Streptomycin inhibits protein synthesis in bacterial cells by binding to the 30S ribosomal subunit and causes misreading of the genetic codes in protein synthesis (29). Streptomycin-resistant strains are distributed in a wide range of plant pathogenic bacteria, such as Xanthomonas oryzae, X. citri, Pseudomonas tabaci, and P. lachrymans. In agricultural use, the alternative or combined applications of streptomycin and other chemicals with different action mechanisms is recommended in order to reduce the development of streptomycin-resistant strains in the field. Mutants of E. coli highly resistant to streptomycin are known to involve modification of the P10 protein of the bacterial ribosome 30S subunit.