Rapid confirmatory identification of Neisseria gonorrhoeae with lectins and chromogenic substrates

A group of five tests utilizing wheat germ and soybean lectins and chromogenic substrates (orthonitrophenyl-beta-D-galactopyranoside, gamma-glutamyl-beta-naphthylamide, and prolyl-beta-naphthylamide derivatives) was used as a rapid (30-min) method for the identification of Neisseria gonorrhoeae. The rapid method agreed with Minitek test results for all 126 N. gonorrhoeae isolates and all 39 nongonococcal isolates tested. Soybean lectin was useful for the identification of rare strains (4 of 126) of N. gonorrhoeae which are not agglutinated by wheat germ lectin. The chromogenic substrates differentiate N. gonorrhoeae from Neisseria meningitidis, Neisseria lactamica, and other Neisseria species which may grow on Thayer-Martin or other selective media.