A method of detecting a specific microorganism comprising contacting said microorganism with bacteriocins from a microorganism of a genus which is taxonomically unrelated to said specific organism. The result of such contact may be utilized to detect the presence of a microorganism belonging to a taxonomically unrelated genus. Radio-labeled or fluorescein-labeled bacteriocins can be reacted with specific bacteria in a biological sample and the presence of such specific bacteria detected by removing excess bacteriocins and determining the presence of fluorescent or radioactive bacteria in the sample. Neisseria gonorrhoeae is identified by spotting bacteriocins on a plate of clinical material; or using a disk impregnated with bacteriocins placed on a plate inoculated with the clinical material; or the bacteriocins can be incorporated into one-half of a split agar plate, the identification being made on the basis of a zone of inhibition surrounding the spot where the bacteriocins were applied, or growth inhibition on the portion of the plate to which the bacteriocins were added.