Tested antimicrobial agents and dilution ranges

AntimicrobialCompanyaOrder no.Dilution range (mg/liter)Breakpoint (mg/liter)bStock concn (mg/ml), diluentc
B. burgdorferi sensu latoRelapsing-fever Borrelia strains
AmoxicillinCentrafarm140295960.25–1280.25–128≤48.89, PBS
DoxycyclineSigma-AldrichD34470.03–80.004–2≤444.4, DMSO
CeftriaxoneSigma-AldrichPHR13820.008–40.008–4≤84.44, PBS
AzithromycinSigma-AldrichPHR10880.0001–0.050.0001–0.05≤25.56, DMSO
AmikacinSigma-AldrichA17742–1,0242–1,024≤1611.26, MKP
  • a Locations: Centrafarm, Etten-Leur, the Netherlands; Sigma-Aldrich, St. Louis, MO, USA.

  • b According to the Clinical and Laboratory Standards Institute.

  • c PBS, phosphate-buffered saline; DMSO, dimethyl sulfoxide; MKP, modified Kelly-Pettenkofer medium. The DMSO concentrations used in our studies did not influence Borrelia viability (data not shown).