STD Update: Chlamydia Stays Simple as Gonorrhea Adapts

Beginning with a joke, as many speakers at the 2017 Pri-Med West meeting in Anaheim, California did, Richard A. Johnson, MD, said that his wife and children were his only financial disclosures. He then gave a thorough update of the current state of care and best practices for the most common sexually transmitted infections (STI). Johnson is a Clinical Professor of Family Medicine, David Geffen School of Medicine at UCLA.

Chlamydia is now the most common STI, with 450 cases per 100,000 people in the United States and a total of 10 million cases annually. It primarily impacts women (at a rate of 3 to 1 compared to men) and babies born of them. It may lay dormant for months or years, and Johnson says it’s “kind of a funny organism,” in that it’s not a disease that always has symptoms, which “makes it an ideal situation” for the art of screening. He describes the disease as indecisive between a virus and a bacteria: it has a cell wall so is defined as a bacteria, but it cannot reproduce in the absence of a human cell.

“This is a disease of 15 to 29 year olds,” he told the room, before rolling through the expected economic differences in prevalence, corresponding with geographic differences. The deep South has the highest prevalence, but Washington D.C. is the city where it has its firmest foothold, which led Johnson into some lighthearted sniping about politics and Senate Pages.

For diagnosis, he repeated the CDC recommendation of using first-catch urine samples to maximize contamination, as opposed to the midstream collection preferred for detection of urinary tract infections or drug tests.

“We’re doing pretty good,” he says of the state of treatment. A 1g dose of azithromycin is still typically sufficient for elimination, as is as a 7-day course of doxycycline. Azithromycin has a strong reputation for curing chlamydia due to its deep tissue penetration and long half life.

According to Johnson, such treatment is so reliable that it’s no longer necessary to test for cure-a waste of resources, he calls it, and he notes that people often test positive up to 3 weeks after elimination anyway, which is no cause for alarm. The CDC, on the other hand, recommends rescreening at 3 months, but not due to treatment failure. Instead, he says, the recommendation comes from an unfortunate trend towards reinfection.

Gonorrhea, on the other hand, has a lower prevalence curve over time and only one fourth as common as chlamydia, affecting the genders equally. It seems to be evolving, though.

“What’s happening with gonococcus is it’s requiring higher and higher drug levels to treat the organism. It’s not becoming specifically resistant…but it’s such that the old recommendation of 125mg intramuscular Rocephin and the 400mg of oral Cefixime aren’t producing high enough tissue levels to be as uniformly effective as they have been in the past,” Johnson explained. “I wouldn’t say resistance, it’s developing stubbornness.”

The recommendations have thus changed to prioritize a higher dose of cephalosporin, and to add in another antibacterial drug. That isn’t so much to treat the gonorrhea as it is a public health effort geared at stunting further adaptation on the part of gonococcus, similar to approaches taken against tuberculosis. It is now recommended, Johnson says, that if the disease is treated with an alternative regimen, a follow-up culture should be taken.

As with chlamydia, he noted that Washington, D.C. had some of the highest rates of gonorrhea in the country, and followed with more jokes.

A key issue still with STI treatment is the legal status of expedited partner treatment (EPT), or the provision of treatment drugs to the patient to be given to unexamined recent sexual partners who may be infected. In several states, including California, Nevada, Wyoming, Colorado, and Pennsylvania, among others, it is within a physician’s rights. “When you give the azithromycin to a patient to give to their partner and they have some allergic reaction, does that mean you won’t get sued? No,” Johnson cracked. For the injectable drugs often required for the eradication of gonorrhea, he noted that EPT can be even more tricky.