In vitro activity of tigecycline against multiple strains of Borrelia burgdorferi.
OBJECTIVE
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.
Yang
Xiaohua
X
Division of Infectious Diseases, Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA.
Nguyen
Andrew
A
Qiu
Dan
D
Luft
Benjamin J
BJ
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D025065:Borrelia burgdorferi / Q000187:drug effects*; D015748:Borrelia burgdorferi Group / Q000187:drug effects; D004318:Doxycycline / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D013987:Ticks; D000078304:Tigecycline; D013997:Time Factors
D000900:Anti-Bacterial Agents; D000078304:Tigecycline; D008911:Minocycline; D004318:Doxycycline