These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The mode of action of quinolones: the paradox in activity of low and high concentrations and activity in the anaerobic environment.
    Author: Lewin CS, Morrissey I, Smith JT.
    Journal: Eur J Clin Microbiol Infect Dis; 1991 Apr; 10(4):240-8. PubMed ID: 1713846.
    Abstract:
    All 4-quinolones that have been examined display rapid bactericidal activity which is biphasic. At concentrations above the MIC, the lethality of the drugs increases until a concentration known as the optimum bactericidal concentration (OBC) beyond which the bactericidal activity then declines. The biphasic response appears to be due to the inhibition of RNA synthesis at concentrations above the OBC, as RNA synthesis is required for the full bactericidal activity of the 4-quinolones. However, differences in the biphasic response are observed as some fluoroquinolones are still able to kill bacteria in the absence of bacterial protein or RNA synthesis, thus reducing the inhibition of bactericidal activity at concentrations above the OBC. It has been proposed that this ability to kill bacteria in the absence of protein or RNA synthesis is due to the possession of an additional bactericidal mechanism by these fluoroquinolones. Oxygen also appears to be essential for the lethality of the clinically available 4-quinolones although it is not required for the drugs to inhibit bacterial multiplication. Therefore these drugs are not bactericidal under anaerobic conditions.
    [Abstract] [Full Text] [Related] [New Search]