There have been lots of warnings that gonorrhea is becoming untreatable, but now a new study gives a glimpse of what could happen if the last treatment option fails. And it's not looking good.

There used to be a number of treatment options for gonorrhea, including the commonly used antibiotic Cipro, but gonorrhea became resistant to Cipro several years ago. More recently, doctors have started using a class of antibiotics called cephalosporins — and because of concerns that gonorrhea could develop resistance to cephalosporins as well, the CDC started recommending a dual treatment in 2010: cephalosporins plus an injected anti-microbial drug.

But the new CDC study, just published online ahead of its April publication in the journal Emerging Infectious Diseases, warns that "the possible emergence and spread of cephalosporin resistance could eventually threaten the effectiveness of this regimen and pose a major public health challenge."

So what happens if gonorrhea does become cephalosporin-resistant? To find out, the CDC looked at what happened to gonorrhea infection rates in cities where gonorrhea samples were showing a high degree of resistance to Cipro, from 1991-2006. The CDC looked at eight cities with a higher than average resistance to Cipro (Denver, Honolulu, Minneapolis, Phoenix, Portland, San Diego, San Francisco, and Seattle) and nine cities with below-average resistance.


And in a nutshell, the cities where gonorrhea was more drug-resistant had a higher rate of incidence of new gonorrhea infections, even though another treatment option was readily available. And if gonorrhea becomes resistant to cephalosporins, that won't be the case — this is the last stop on the road before untreatable gonorrhea. So the CDC warns that the rate of new infections could spike much more quickly in a scenario where cephalosporins stop working. This confirms the results of some mathematical models.


So why does gonorrhea spread more quickly if the drugs stop working? The CDC offers two possible explanations. For one, people tend to be infected for longer — even when there was an available alternative treatment — and thus have more chance to infect others. But the second explanation is more alarming: gonorrhea that became resistant to drugs also mutated to infect people more easily. Or, as the CDC puts it, "mutational changes in the organism that conferred resistance or co-occurred with resistance determinants might have supported gonococcal transmission."

All in all, plenty of reason to be alarmed at the possibility of a post-antibiotic future.


Read the whole study here.