Image: Infection and Immunity
People who have been infected with chlamydia and received treatment may be prone to reinfecting themselves—without re-exposing themselves to the bacteria. That's the unfortunate finding of a new study published in the journal Infection and Immunity.
The unexpected discovery of an STD has caused many-a-rift in a relationship, if television shows like House are to be believed. It's sometimes used as a plot device to prove a significant other was cheating (or never stopped cheating), and, when they try to fall back on some other sort of explanation, it’s usually debunked by a doctor. I have no idea if this occurs in actual, real-life relationships, but I assume it at least occasionally does.
Well, new research from scientists at the Arkansas Children’s Research Institute would make for a good plot point in some medical drama: After infection, chlamydia persistently exists in the gut, even when antibiotics kill the disease in the genitals, and it may sometimes reinfect its host. Researchers demonstrated that it definitely happens in mice, and believe that it can happen in humans as well.
“We propose that women, cured of genital infection, remain at risk for auto-inoculation from the lower gastrointestinal tract,” Roger Rank, the study’s lead author writes. “It is possible that women, cured of genital infection by antibiotics, remain infected in the gastrointestinal tract and can become reinfected by auto-inoculation from that site.”
Chlamydia is the most common sexually transmitted disease in the United States and Europe, with roughly 1.2 million cases reported to the CDC each year. It’s also the STD with the highest reinfection rate: Roughly 26 percent of people infected end up getting the disease again. The CDC notes that “chlamydia reinfection is common even when individuals are properly diagnosed and treated, because of untreated infection in their sexual partners.” Often, chlamydia can lie dormant for years without causing symptoms, which is one of the reasons why infection rates are so high and why many cases of it go untreated. This ability to lie dormant may also have something to do with why the bacteria can remain in the digestive system even if it has been eliminated elsewhere. Rank notes that GI infection is most likely to occur when chlamydia is transmitted via oral or anal sex, in case you were wondering.
Rank says that there have been cases of chlamydia treatment failures, but it’s possible that it’s reinfection from a persisting disease.
“In a small percentage of recurrent infections, infection cannot be attributed to reinfection from a partner or treatment failure; so it would appear that in these cases, the organism has remained persistent in the individual,” he writes. “Based on the studies in animals and the experimental mouse model studies and evidence for gastrointestinal infection in humans, we propose that chlamydiae shed in the GI tract may infect the genital tract via auto-inoculation.”
Previous studies have found that women are more likely to have these recurrent infections that happen even when study participants haven’t had sexual intercourse in between doctor’s visits. Two things would explain that—treatment failures that could occur because of antibiotic resistance, or reinfection. Rank says that, though treatment failure in chlamydia is rising, in mice studies, antibiotics were much less effective on GI chlamydia than on genital chlamydia. Rank suggests that women suffer self-reinfection at a higher rate than men for the same reason that they are more likely to have urinary tract infections. He says that alternative antibiotics or closer monitoring might be necessary to ensure a patient is cured.
Rank still needs to do further tests in human subjects, but until then, at least you’ve got something else to scare yourself about—and something for TV writers to base their next dramatic script on.