Hickman R K, Lawson J W
J Clin Microbiol. 1980 Oct;12(4):603-5. doi: 10.1128/jcm.12.4.603-605.1980.
A cell wall-defective form of Neisseria gonorrhoeae from an exudate of an untreated patient with gonococcal urethritis was isolated on medium containing 7% polyvinylpyrrolidone. Initial attempts to grow the organism by standard microbiological methods had failed. This isolate was incapable of reversion to a normal gonococcus even after numerous subcultures and appeared to be a stable cell wall-defective form.