The research, published in the Journal of the American Medical Association, found that nine of 133 patients with gonorrhea at a Toronto clinic still had the disease after a round of cephalosporins, the last effective oral antibiotic for treatment.

"Its arrival is deeply troubling," Dr. Robert D. Kirkcaldy of the Division of STD Prevention of Centers for Disease Control and Prevention (CDC) said in a press release. "Clinicians now face the emergence of cephalosporin-resistant N. gonorrhoeae without any well-studied, effective backup treatment options."