The mechanism of action of streptomycin as revealed by normal and abnormal division in streptomycin-dependent Salmonellae

Streptomyces from traditional medicine: sources of new innovations in antibiotic discovery

Given the increased reporting of multi-resistant bacteria and the shortage of newly approved medicines, researchers have been looking towards extreme and unusual environments as a new source of antibiotics. Streptomyces currently provides many of the world's clinical antibiotics, so it comes as no surprise that these bacteria have recently been isolated from traditional medicine. Given the wide array of traditional medicines, it is hoped that these discoveries can provide the much sought after core structure diversity that will be required of a new generation of antibiotics. This review discusses the contribution of Streptomyces to antibiotics and the potential of newly discovered species in traditional medicine. We also explore how knowledge of traditional medicines can aid current initiatives in sourcing new and chemically diverse antibiotics.

Gentamicins

Gentamicin is a new broad-spectrum antibiotic, basic and water-soluble, produced and developed by Schering Corporation-Bloomfield, New Jersey (1967 and 1968). It is produced by Micromonospora purpurea, a member of a genus of microorganisms from which no other antibiotics have been derived. Paper chromatographic techniques showed the components of gentamicin complex designated as C', C'a, and C2. Gentamicins are bactericidal antibiotics, active in vivo in low concentrations against a wide spectrum of both Gram-positive and Gram-negative organisms. Among the responsive Gram-positive groups of microorganisms are Staphylococcus aureus including many resistant penicillinase producing strains and group A betahemolytic Streptococci. Among the clinically more important species of Gram-positive organisms responsive to gentamicin are both indole-positive and indole-negative Proteus, Pseudomonas, Escherichia coli, Aerobacter, Klebsiella, Salmonella, and Shigella. The production of gentamicins was improved by adding cobalt to the growth medium.

Sensitivity of Cultured Mammalian Cells to Streptomycin and Dihydrostreptomycin

Cultured mammalian cells killed by streptomycin were essentially unaffected by an identical concentration of dihydrostreptomycin.

LETHALITY OF STREPTOMYCIN FOR ALKALINE PHOSPHATASE CONSTITUTIVE ESCHERICHIA COLI

Rosenkranz, Herbert S. (Columbia University, New York, N.Y.) and Howard S. Carr . Lethality of streptomycin for alkaline phosphatase constitutive Escherichia coli . J. Bacteriol. 85: 751–753. 1963.—An alkaline phosphatase constitutive strain of Escherichia coli was more sensitive to streptomycin in a phosphorus-rich medium than was the wild parent strain. In a low-phosphorus medium, the efficiency of killing by streptomycin was nearly the same for both strains. The greater sensitivity displayed by the alkaline phosphatase constitutive strain in the phosphorus-rich medium was ascribed to the absence of internal inorganic phosphates in these bacteria. It has been shown that such anions interfere in the reaction of the antibiotic with deoxyribonucleic acid.

GROWTH OF L FORMS OF STREPTOMYCIN-DEPENDENT PROTEUS MIRABILIS

Altenbern, Robert A. (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.). Growth of L forms of streptomycin-dependent Proteus mirabilis . J. Bacteriol. 85: 619–622. 1963.—A streptomycin-dependent mutant of Proteus mirabilis produces L forms on penicillin-containing medium when dihydrostreptomycin is also present. The 3A-type L form grows at maximal rate when the concentration of dihydrostreptomycin is between 10 and 50 μg/ml, whereas the 3B-type L form grows appreciably only at concentrations of dihydrostreptomycin of 500 μg/ml or more. These results strongly suggest that propagation of 3A-type L forms does not proceed through intermediate formation of a 3B-type L body. The low quantitative dihydrostreptomycin requirement for growth of the 3A-type L forms indicates an abnormal membrane as compared with the 3B-type L forms or the normal cells of this streptomycin-dependent mutant.