Silver nanoparticles as a new generation of antimicrobials.

Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports

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Antiseptics and Disinfectants: Activity, Action, and Resistance

Structure, Recognition, and Processing of Cisplatin-DNA Adducts.

Mechanisms of membrane toxicity of hydrocarbons.

A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties

Studies with hydroxyurea: I. The reversible inhibition of bacterial DNA synthesis and the effect of hydroxyurea on the bactericidal action of streptomycin

Isolates (657) representing 22 bacterial species were tested for susceptibility to silver sulfadiazine. All of the strains tested were inhibited by concentration levels of the drug which are easily achieved topically. It is suggested that silver sulfadiazine may be useful as a broad-spectrum antimicrobial substance for the prevention and treatment of infections of burns and wounds.

Silver Sulfadiazine: In Vitro Antibacterial Activity

Rosenkranz, Herbert S. (Columbia University, New York, N.Y.), Howard S. Carr, and Harry M. Rose. Phenethyl alcohol. I. Effect on macromolecular synthesis of Escherichia coli. J. Bacteriol. 89:1354–1369. 1965.—An investigation of the mode of action of phenethyl alcohol produced the following results. Phenethyl alcohol had no effect on the physicochemical properties of isolated deoxyribonucleic acid (DNA). The DNA isolated from phenethyl alcohol-treated bacteria had physicochemical properties identical with those of DNA isolated from normal cells. The metabolic functions most sensitive to the inhibitory action of phenethyl alcohol appeared to be the process of enzyme induction and, possibly, the synthesis of messenger ribonucleic acid. Phenethyl alcohol did not affect the polyuridylic acid-mediated synthesis of polyphenylalanine in a cell-free amino acid-incorporating system.

Phenethyl Alcohol I. Effect on Macromolecular Synthesis of Escherichia coli

Even though the addition of silver sulfadiazine (AgSu) to purified deoxyribonucleic acid (DNA) results in the formation of AgSu-DNA complexes, no such complexes were detected in bacteria treated with AgSu. AgSu blocked macromolecular syntheses in treated bacteria, DNA synthesis being slightly more sensitive to this inhibitory action. The ribosomes, ribonucleic acid, and DNA isolated from treated cells were normal qualitatively. Bacteria deficient in DNA polymerase were not more sensitive than their parent strain to the lethal action of AgSu. Radioactive AgSu was localized mainly in the cytoplasmic membrane fraction of treated cells.

Silver Sulfadiazine: Effect on the Growth and Metabolism of Bacteria

Thin sections of Escherichia coli were examined by electron microscopy at sequential intervals after addition and then removal of chloramphenicol. The first changes, occurring at 1 hr after exposure to the drug, were disappearance of the ribosomes and aggregation of the nuclear material toward the center of the bacteria. At 2 hr, aggregates of abnormal cytoplasmic granules first appeared and subsequently increased in size. By 23 hr, amorphous, electron-dense material had accumulated within, and at the periphery of, the nuclear matrix. With the removal of chloramphenicol, the bacteria became normal in appearance, passing through a series of stages that were sequential but not synchronous. At 145 min after removal of chloramphenicol, bacteria were encountered in the process of abnormal division. The influence of deoxyribonucleic acid and ribonucleic acid synthesis, and of energy metabolism, upon the changes seen electron microscopically in chloramphenicol-treated cells, was investigated by selectively inhibiting these functions with hydroxyurea, azauracil, and sodium azide, respectively.

Howard S. Carr

Papers

Studies with hydroxyurea: I. The reversible inhibition of bacterial DNA synthesis and the effect of hydroxyurea on the bactericidal action of streptomycin

Silver Sulfadiazine: In Vitro Antibacterial Activity

Phenethyl Alcohol I. Effect on Macromolecular Synthesis of Escherichia coli

Silver Sulfadiazine: Effect on the Growth and Metabolism of Bacteria

Electron microscopy of chloramphenicol-treated Escherichia coli.