Detection of borreliacidal antibodies in Lyme borreliosis patient sera containing antimicrobial agents

The borreliacidal-antibody test has been used for the serological detection and confirmation of Lyme borreliosis. However, the presence of antimicrobi al agents in serum can confound the accurate detection of borreliacidal ant ibodies. In this study, we developed a Bacillus subtilis agar diffusion bio assay to detect small concentrations of antimicrobial agents in serum. We a lso used XAD-16, a nonionic polymeric resin, to adsorb and remove high conc entrations of amoxicillin, cefotaxime, ceftriaxone, cefuroxime, doxycycline , and erythromycin without significantly affecting even small concentration s of immunoglobulin M (IgM) or IgG borreliacidal antibodies. High concentra tions of penicillin could also be removed by adding 1 U of penicillinase wi thout significantly influencing the levels of borreliacidal antibodies. The se simple procedures greatly enhance the clinical utility of the borreliaci dal-antibody test.