Evaluation of plasmids in tetracycline resistant strains of Neisseria gonorrhoeae and Ureaplasma urealyticum in a case of severe urethritis.

A young man who acquired gonococcal urethritis in the Far East was not cured by repeated i.v. treatment with a broad-spectrum penicillin. Cultures of pre- and post-treatment urethral specimens grew tetracycline-resistant penicillinase-producing Neisseria gonorrhoeae (PPNG) and tetracycline-resistant Ureaplasma urealyticum. The patient was successfully treated with erythromycin, to which both isolates were sensitive. The strain of N. gonorrhoeae carried a novel plasmid of 10.5 Md molecular mass in addition to plasmids previously observed in this organism. The strain of U. urealyticum carried two distinct plasmids, one with mass 4.9 Md and the other one with mass 8.1 Md. This report demonstrates that ureaplasmas can contain plasmids and raises the question if tetracycline resistance is controlled by plasmids or by the chromosome.