Tigecycline bettr than Doxycycline? research

Discussion in 'Lyme Disease Archives' started by victoria, Feb 13, 2009.

  1. victoria

    victoria New Member

    Original research

    In vitro activity of tigecycline against multiple strains of Borrelia burgdorferi
    Xiaohua Yang, Andrew Nguyen, Dan Qiu and Benjamin J. Luft

    Journal of Antimicrobial Chemotherapy,
    Advance Access published online on January 31, 2009


    Objectives: To compare the antimicrobial activity of tigecycline and doxycycline against multiple isolates of Borrelia burgdorferi.

    Methods: In vitro antimicrobial assays were carried out using a microdilution assay. The time needed to inhibit, immobilize and kill the B31 strain of B. burgdorferi was determined. The MIC, MBC and concentration needed to immobilize the organism were determined for each antimicrobial for various strains of B. burgdorferi.

    Results: Tigecycline inhibited the growth of and killed the organism more rapidly than doxycycline. Tigecycline was able to kill B. burgdorferi within 24 h at clinically achievable concentrations (<1 mg/L). In contrast, doxycycline was bacteriostatic and required 48–72 h to achieve its maximal inhibitory effect. The anti-Borrelia activity of the antibiotics was tested against 20 different isolates from three species. Tigecycline was 16- to 1000-fold more active than doxycycline at immobilizing Borrelia for the 20 isolates tested.

    Conclusions: We demonstrate that the in vitro activity of tigecycline against B. burgdorferi is superior to that of doxycycline. Tigecycline acted more rapidly and was bactericidal, whereas doxycycline was bacteriostatic and required a more prolonged co-incubation to achieve its maximal inhibitory effect.

    Received 30 July 2008; returned 16 October 2008; revised 14 November
    2008; accepted 23 December 2008