The effects of colchicine in phagocytosis of strain PC4-6P. FITC-labelled strain PC4-6P was used in phagocytosis assays to test the effects of colchicine. After 1 h, extracellular bacteria were detected with a H. parasuis-specific antiserum coupled with a phycoerythrin-secondary antibody and macrophages were analysed by flow cytometry. Results are presented as the percentage of macrophages with total bacteria (black bars), internalized bacteria (dark grey bars) and surface associated bacteria (light grey bars).