Development of Colloidal Gold Immunochromatographic Strips for Detection of Riemerella anatipestifer

Riemerella anatipestifer is one of the most important bacterial pathogen of ducks and causes a contagious septicemia. R . anatipestifer infection causes serositis syndromes similar to other bacterial infections in ducks, including infection by Escherichia coli , Salmonella enterica and Pasteurella multocida . Clinically differentiating R . anatipestifer infections from other bacterial pathogen infections is usually difficult. In this study, MAb 1G2F10, a monoclonal antibody against R . anatipestifer GroEL, was used to develop a colloidal gold immunochromatographic strip. Colloidal gold particles were prepared by chemical synthesis to an average diameter of 20±5.26 nm by transmission electron microscope imaging. MAb 1G2F10 was conjugated to colloidal gold particles and the formation of antibody-colloidal gold conjugates was monitored by UV/Vis spectroscopy. Immunochromatographic strips were assembled in regular sequence through different accessories sticked on PVC plate. Strips specifically detected R . anatipestifer within 10 min, but did not detect E . coli , S . enterica and P . multocida . The detection limit for R . anatipestifer was 1×10 6 colony forming units, which was 500 times higher than a conventional agglutination test. Accuracy was 100% match to multiplex PCR. Assay stability and reproducibility were excellent after storage at 4°C for 6 months. The immunochromatographic strips prepared in this study offer a specific, sensitive, and rapid detection method for R . anatipestifer , which is of great importance for the prevention and control of R . anatipestifer infections.