In vitro activity of vancomycin against the spirochete Borrelia burgdorferi.
Borrelia burgdorferi, a spirochete and the causative agent of Lyme disease, has been reported to be susceptible to a variety of antimicrobial agents. In this investigation, the action of vancomycin, a glycopeptide antibiotic not previously known to have activity against spirochetes, against borrelias was examined. The in vitro activity of vancomycin against a variety of strains of B. burgdorferi and one strain of Borrelia hermsii was determined by use of a microdilution MIC method (L.L. Dever, J.H. Jorgensen, and A.G. Barbour, J. Clin. Microbiol. 30:2692-2697, 1992). MICs ranged from 0.5 to 2 micrograms/ml. MICs of the glycopeptides ristocetin and teicoplanin and the lipopeptide daptomycin against strain B31 of B. burgdorferi were all > or = 8 micrograms/ml. Subsurface plating, time-kill studies, synergy studies, and electron microscopy were used to investigate further the activity of vancomycin against B31. The MBC of vancomycin was 2 micrograms/ml. Time-kill curves demonstrated > or = 3-log10-unit (99.9%) killing of the final inoculum after 72 h by vancomycin concentrations twice the MIC. Synergy between vancomycin and penicillin was demonstrated at concentrations one-fourth the MIC of each drug. In electron microscopy, B31 cells exposed to vancomycin showed a disruption of cellular integrity and were indistinguishable from those exposed to penicillin. These studies demonstrate another class of microorganisms susceptible in vitro to vancomycin.
Department of Medicine, University of Texas Health Science Center, San Antonio 78284-7881.
L L
LL
Dever
J H
JH
Jorgensen
A G
AG
Barbour
D015748:Borrelia burgdorferi Group / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D004357:Drug Synergism; D008193:Lyme Disease / Q000188:drug therapy / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D010406:Penicillins / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology*
D010406:Penicillins; D014640:Vancomycin