Rapid Immunodot Technique for Identifying Bordetella Pertussis

We developed and evaluated a rapid test with monoclonal antibodies to identify cultures of Bordetella pertussis. Samples of 5 microliters of cells suspended in formalin-saline were dried onto a nitrocellulose disk. The disk was placed in a filtration device, and 5-microliters volumes of murine monoclonal antibody directed against B. pertussis lipooligosaccharide and peroxidase conjugate were added consecutively, with washing after each addition. The disk was removed and immersed in peroxidase substrate solution. All of 66 B. pertussis isolates confirmed by direct fluorescent-antibody assay were correctly identified by using four different monoclonal antibodies. One of the monoclonal antibodies did not react with over 20 bacterial species tested, including other Bordetella, Acinetobacter, Haemophilus, Moraxella, Mycobacterium, Neisseria, and Staphylococcus spp. This technique detected > or = 2 micrograms of lipooligosaccharide per ml or > or = 5 x 10(8) B. pertussis cells per ml. This rapid procedure used small amounts of reagents, needed less equipment, and was less subjective and more specific than the direct fluorescent-antibody assay.