Multicenter Evaluation of the C6 Lyme ELISA Kit for the Diagnosis of Lyme Disease.

Lyme disease (LD), caused by infection with Borrelia burgdorferi, is the most common tick-borne infection in many regions of Eurasia. Antibody detection is the most frequently used laboratory test, favoring a two-step serodiagnostic algorithm; immunoenzymatic detection of antibodies to C6 has been shown to perform similarly to a standard two-step workflow. The aim of this study was the performance evaluation of the C6 Lyme ELISA kit compared to a standard two-step algorithm in three laboratories located in the northeastern region of Italy which cater to areas with different LD epidemiology. A total of 804 samples were tested, of which 695 gave concordant results between C6 testing and routine workflow (564 negative, 131 positive). Wherever available, clinical presentation and additional laboratory tests were analyzed to solve discrepancies. The C6 based method showed a good concordance with the standard two-step algorithm (Cohen's κ = 0.619), however, the distribution of discrepancies seems to point towards a slightly lower specificity of C6 testing, which is supported by literature and could impact on patient management. The C6 ELISA, therefore, is not an ideal stand-alone test; however, if integrated into a two-step algorithm, it might play a part in achieving a sensitive, specific laboratory diagnosis of LD.

A fast centrifuge method for nematocyst isolation from Pelagia noctiluca Forskal (Cnidaria: Scyphozoa).

Nematocyst isolation from surrounding tissue is an important step to characterize Cnidarian venom. Although several protocols have been used to extract venoms from cnidarian tissues, the complete isolation of nematocysts from tissue is still difficult. The goal of the present work was to evaluate the effectiveness of three different media, Percoll, Ficoll and Methylcellulose in isolating nematocysts from Pelagia noctiluca tentacles by centrifugation. The complete sedimentation of nematocysts and tissue fragments to the bottom of the test tubes was observed in Ficoll and Methylcellulose suspensions. The best result was obtained using a discontinuous density gradient of Percoll: three types of nematocysts were concentrated in three different fractions along the density gradient. Protein assay and preliminary chromatographic analyses confirmed these results.