Neisseria gonorrhoeae
The disease is classified as either gonococcal urethritis, caused by "Neisseria gonorrhoeae", or non-gonococcal urethritis (NGU), most commonly caused by "Chlamydia trachomatis," which is accounted for 20-50% of routinely tested cases. NGU, sometimes called nonspecific urethritis (NSU), has both infectious and noninfectious causes.