STD Awareness: Fully Antibiotic-Resistant Gonorrhea Is on the Horizon

shot-in-armWe’ve been anticipating its arrival for years now, but earlier this fall, the Centers for Disease Control and Prevention (CDC) finally made an announcement: Cases of gonorrhea resistant to the last drugs we use to cure it are emerging.

Over the years, gonorrhea has evolved resistance to every drug we’ve thrown at it — sulfonamides, penicillins, tetracyclines, macrolides, fluoroquinolones, and narrow-spectrum cephalosporins. The last line of defense we have is a one-two punch of a pair of antibiotics: azithromycin and ceftriaxone. By using two drugs, we can delay the inevitable evolution of antibiotic resistance by attacking the bacteria in two vulnerable locations, rather than just one, making it more difficult for the bug to mount a defense and pass on its superior survival skills to subsequent generations.

Prevention is paramount: Stop the spread of antibiotic resistance by practicing safer sex!

Unfortunately, we could only stave off the inevitable for so long. At their conference in September, the CDC announced a cluster of gonorrhea infections that are highly resistant to azithromycin, and that fall prey only to high doses of ceftriaxone. As gonorrhea’s tolerance to ceftriaxone increases, the infection will get more and more difficult to cure.

This cluster of drug-resistant cases was identified in Honolulu in April and May of this year, with five infections showing “dramatic” resistance to azithromycin, as well as reduced vulnerability to ceftriaxone. The good news is that these cases were cured with higher-than-usual doses of antibiotics, but the bad news is that dosages can only climb so high before a drug is no longer considered to be an effective treatment.

In the United States, antibiotic-resistant gonorrhea has typically emerged in Hawaii, as resistance seems to enter the country from the west. If this cluster of cases follows historical trends, new strains of highly resistant gonorrhea will soon show up in California and move across the country.

Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, warned that “if resistance continues to increase and spread, current treatment will ultimately fail and 800,000 Americans a year will be at risk for untreatable gonorrhea.” When gonorrhea is not treated, risk for infertility, pelvic inflammatory disease, and ectopic pregnancy goes through the roof. In fact, in the pre-antibiotic era, gonorrhea was a top cause of infertility, and there were no adequate treatments for the infection until the discovery of penicillin.

Discovering, developing, and testing new antibiotics takes years — and a ton of money. And, once an antibiotic hits the market, it’s only a matter of time before evolution works its annoying magic. (“Fun” fact: Penicillin was introduced in 1938, and drug resistance was first observed in 1945. So evolution doesn’t take long, especially in organisms whose life-cycles are counted in mere hours rather than years.) Because there are no “backup” drugs to use if current treatment options fail to cure a gonorrhea infection, it’s imperative that scientists develop novel antibiotics, which ideally should be able to attack gonorrhea bacteria in different parts of their cells, where they haven’t already evolved stronger defenses.

One promising drug under development is called ETX0914 (aka zoliflodacin), and it may prove to be the drug doctors are looking for — one that can deliver a knockout punch to bacteria using a different strategy than all the antibiotics that came before it. While azithromycin interferes with the bacteria’s ability to make proteins, and ceftriaxone causes the cell wall to fall apart, this new drug acts on a crucial protein involved in bacterial DNA replication. It’s important that a new gonorrhea drug attacks the bacteria in a new way, because the bugs haven’t yet evolved strategies for defending themselves against these types of attacks.

Even better, it is hoped that ETX0914 could cure gonorrhea in just one oral dose — much nicer than taking a daily regimen of pills, or receiving a painful shot of an injectable drug. So far, only a small human trial has reported results, but the cure rate was very high — all 47 patients receiving 3 grams of the drug were cured, while only one of 49 patients receiving the 2 gram dose failed to respond. Even better, side effects were mild. The next step is to test the drug in larger clinical trials.

Unfortunately, one promising early trial isn’t a guarantee that ETX0914 will be the magic bullet we’re hoping for; only time will tell if this lead pans out. For now, the azithromycin/ceftriaxone combo still works, so testing and treatment are paramount — as is prevention! Sexually active people should use latex barriers, such as condoms and dental dams, during vaginal, anal, and oral sex. They should also keep up-to-date on their STD status by receiving screening and treatment for gonorrhea. You can drop by to pick up condoms, or make an appointment to be tested for gonorrhea, at any Planned Parenthood health center.

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