Isolation of Cyclospora oocysts from fruits and vegetables using lectin-coated paramagnetic beads

Published techniques for recovering parasites from fruit and vegetables are generally inadequate, with low and variable recovery efficiencies. Herein, we describe an improved method for analyzing fruit and vegetables for Cyclospora oocysts. The technique includes washing procedures, sonication, and separation using lectin-coated paramagnetic beads. Identification is by microscopy (differential interference contrast and fluorescence). Oocyst recovery efficiencies from mushrooms, lettuce, and raspberries were approximately 12%. Recovery efficiencies from bean sprouts were approximately 4%. Although no significant difference in recovery efficiency could be detected between samples processed using the lectin-coated beads and samples processed without this procedure, distinct advantages were apparent when the lectin-coated beads were used. A considerably smaller, cleaner final volume remained for microscopy, which increases the sensitivity of the technique and reduces operator time.