The specificity of pilin DNA sequences for the detection of pathogenic Neisseria

A nucleic acid hybridization assay for the detection of the pilin gene of Neisseria gonorrhoeae has been devised. The method involves solution hybridization of pilin specific synthetic oligonucleotide probes to genomic DNA in crude cell lysates. This is followed by capture of the probe-target complex onto a microtitre dish well, signal amplification and labelling based on horseradish peroxidase conjugated to oligonucleotides. Detection is achieved with a chemiluminescent enzyme substrate. With a detection limit of about 20,000 cells, the 4-h assay is as sensitive as a radioactive dot-blot method. Over 150 strains of Neisseria gonorrhoeae collected from a variety of sources were detected with the assay. Several N. meningitidis serogroups were also found to react positively. No reactivity was observed with non-pathogenic Neisseria spp. or with other known pathogenic or normal microbial inhabitants of the human urogenital tract.