Identification of Neisseria gonorrhoeae by carbohydrate disc reactions on a modified fermentation medium

The identification of Neisseria gonorrhoeae by the use of a carbohydrate disc reaction on a modified fermentation medium is described. 70 out of the 71 strains tested produced detectable acid in 18--24 hours from the dextrose disc and no acid from Maltose, sucrose or lactose discs. One strain required 48 hours for good growth and acid production from dextrose disc only. The carbohydrate disc method was compared with a standard fermentation method using sugars incorporated in serum-free medium, 64 out of 71 strains of gonococci tested were identified after 18--24 hours incubation. All the strains gave clear-cut confirmatory results after 48 hours incubation. The importance of serum-free fermentation media in the identification of gonococci in tropical areas where meningococcal infections are also prevalent is discussed.