STD Awareness: Is Mouthwash a Match for Gonorrhea’s Superpowers?

Since the 1930s, we’ve enjoyed around eight decades of easily cured gonorrhea — at least in places with easy access to antibiotics — but experts fear those days are numbered. In the past year or so, cases of untreatable gonorrhea have occasionally made headlines.

Thanks to the powers of evolution, some bacteria have acquired the multiple genes necessary to withstand the onslaught of the pills and shots administered by doctors. Gonococci, the bacteria that cause gonorrhea, are starting to win this “arms race” with humans, whose antibiotic arsenals are losing effectiveness. And with gonorrhea on the rise, gonococci may be evolving at an ever-quickening clip.


In 1879, Listerine claimed to cure gonorrhea. Today, scientists are finally testing that claim. We await the results.


Oral Gonorrhea: The Silent Scourge

Many experts believe oral gonorrhea is a key driver of antibiotic resistance. These infections usually don’t cause symptoms, and without symptoms people usually don’t seek treatment. Without treatment, gonococci can hang out in a throat for up to three months.

After transmission by oral sex — and possibly even by kissing  — gonococci can set up camp in the throat, which is an ideal environment for acquiring antibiotic resistance. They might not be causing symptoms, but they’re not sitting there twiddling their thumbs, either. If there’s one thing gonococci love to do, it’s collecting genes like some of us collect trading cards, and the throat is a gathering place for closely related bacteria species that hand out antibiotic-resistance genes for their expanding collections.

Gonococci can easily scavenge DNA from their surroundings — say, from a dead bacterium — and patch long segments of these genes into their own DNA, creating genetic hybrids between themselves and other organisms. Last month, scientists from Indiana University caught this phenomenon on video for the first time.

The video on the left shows Vibrio cholerae, the bacteria species that causes cholera, launching a “harpoon” to snag some genetic debris and reel in its catch. Gonococci have a similar system — though their harpoon is even faster — so it’s likely they perform this feat in a similar manner.

The weeks or months gonococci spend chilling out in the throat could turn out to be surprisingly productive — they encounter a variety of bacteria with antibiotic-resistance genes to share, and have a couple of different ways to grab those genes for themselves. By the time gonococci make their way to their next host, they could be less susceptible to antibiotics.

Preventing Oral Gonorrhea: Condoms, Definitely; Mouthwash, Maybe?

The best way for sexually active people to avoid gonorrhea is to use barriers, such as condoms and dental dams, for vaginal, anal, and oral sex. Unfortunately, many people do not use protection for oral sex, due in part to the widespread — and mistaken — notion that oral sex is a very low-risk activity. While condom use must be encouraged, it would also be helpful to find additional prevention strategies.

In 1879, decades before antibiotics were developed, Listerine advertised itself as a cure for gonorrhea — with no scientific evidence to back up their claims. It’s only been in the past few years that scientists started to look into it. Although alcohol-based Listerine kills gonococci in petri dishes, that doesn’t mean it works in human throats. One worry is that gonococci can hide in a throat’s nooks and crannies, sheltered from a deluge of mouthwash. Indeed, two surveys of men’s real-life mouthwash use found it had no significant effect on oral gonorrhea risk.

However, neither of those studies looked at what types of mouthwash men were using, how long they were using it, and if they were gently swishing it around in their mouths or full-on gargling it. These variables could very well make a difference. A study of men with oral gonorrhea found that 84 percent of them still tested positive for infection after gargling with saline for a full minute, while 52 percent were still positive after gargling for a minute with Listerine. However, those results only held true for the surface of the throat — gonococci were more likely to persist deeper into the throat, and mouthwash was not found to have any significant effect in the farthest recess that was tested. And even if mouthwash did give you a fifty-fifty shot of getting gonococci off the surface of your throat, it still wouldn’t hold a candle to condoms.

But one-time mouthwash use for an established infection isn’t the same as the long-term use of mouthwash to prevent infections from taking hold in the first place. Could using the right mouthwash in the right way slay invading gonococci before they have a chance to colonize the throat? One large trial is currently underway in Australia to answer precisely that question. As is the case with so many health-related mysteries, more studies need to be done to discover if mouthwash can reduce risk for oral gonorrhea — and, if so, what chemicals are most effective, how long one must gargle, and what amount of mouthwash works best. On the flip side, scientists also need to learn if its regular use might increase susceptibility to other sexually transmitted infections or is harmful in other unanticipated ways.

If you are sexually active, it’s best to avoid getting gonorrhea in the first place. First, know your STD status and your partner’s STD status by getting tested together. Second, practice safer sex — especially if you don’t know your partner’s STD status. The wily gonococci have acquired the ability to outsmart all of our antibiotics, and it’s a matter of time before these strains achieve dominance in the sexual wilds. As we say at Planned Parenthood Arizona, use condom sense!


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