Methods: B. burgdorferi, B. afzelii, or B. garinii were cultured in Barbour-Stoenner-Kelly media and cell counts were obtained by automated cell counting prior to spiking into blood. Samples (1.75mL) were processed by lysing red blood cells, concentrating target cells, and amplifying target cell DNA after cell disruption. Amplicons were hybridized to DNA-probe conjugated superparamagnetic particles. Presence of target amplicons were determined by the T2MR signal, which is ~10x higher for amplicon-bound and clustered particles than for amplicon-free and unclustered particles. Frozen samples (n=66) were obtained from cases of suspected Lyme disease characterized by symptoms, erythema migrans (EM), and results of EIA, WB, and/or PCR tests.
Results: Limits of detection (≥95% hit rate for n≥40 replicates) were 8 cells/mL for B. burgdorferi and B. garinii and 5 cells/mL for B. afzelii with no incidence of false positives. Among the 22 most probable clinical samples, classified by at least 2 positive EIA, WB, or PCR tests, 41% were positive for B. burgdorferi by T2MR. Five cases with EM and negative EIA or WB result were positive by T2MR. Two cases with EM and initial negative or equivocal EIA results that later seroconverted in a return visit were positive by T2MR. In 20 samples tested with PCR and T2MR, agreement was found on 1 positive and 12 negative samples. T2MR detected Borrelia in 7 samples reported negative by PCR.
Conclusion: Spiked blood mimicking spirochaetemia levels of ≥5-8 cells/mL were directly detected in blood using T2MR. B. burgdorferi cells were also detected in a subset of clinical samples from patients suspected of early-stage Lyme disease, including samples that would not have been diagnosed using conventional methods.
J. Townsend, T2 Biosystems: Employee and Shareholder , Salary
H. Giese, T2Biosystems: Employee and Shareholder , Salary
H. U. Thomann, T2 Biosystems: Employee and Shareholder , Salary
R. Shivers, T2 Biosystems: Employee , Salary
A. Schotthoefer, T2 Biosystems: Research Contractor , Salary
T. Fritsche, None
C. Green, None
S. Callister, None
L. Neely, T2 Biosystems: Employee and Shareholder , Salary
T. Lowery, T2 Biosystems: Employee and Shareholder , Salary
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