Which sexually transmitted disease cannot be cured with antibiotics

Infectious diseases specialist Kristin Englund, MD, has not seen a patient with antibiotic-resistant gonorrhea -- yet.

“But, unfortunately, we anticipate that it’s coming, and that’s pretty scary,” says Englund, of the Cleveland Clinic. “We have no other antibiotics to use against gonorrhea.”

The sexually transmitted disease is among infections that are becoming most difficult to treat due to antibiotic resistance.

The CDC says that gonorrhea is among three diseases called “urgent threats” for their potential to become more widespread. This means that many of the antibiotics once used to treat it no longer work. Currently, the CDC recommends a single 500-mg injection of ceftriaxone.

Other STDs, such as syphilis and chlamydia, have shown early signs of antibiotic resistance.

The threat prompted the World Health Organization last year to release new guidelines for treating the three STDs. The organization says drug resistance “has increased rapidly in recent years and has reduced treatment options.”

Eventually, health officials fear, current antibiotics will no longer be effective against gonorrhea. There have been cases that do not respond to antibiotics usually used to treat them. In the U.S., there’s evidence that the current recommended treatment may be weakening. In September, a cluster of seven cases in Hawaii showed resistance to the last line of treatment. This was an alarming first.

What is antibiotic resistance, and how does it develop?

Antibiotics have been widely used to fight infections, including sexually transmitted diseases like gonorrhea, for more than 75 years. However, the bacteria that cause STDs have fought back. Over time, they have adapted so that a growing number of antibiotics can no longer treat them.

Each year, according to the CDC, at least 2 million people in the U.S. pick up these difficult-to-treat infections, which include a growing number of gonorrhea cases that are resistant to antibiotics.

They develop resistance in two ways, says Jeffrey Klausner, MD, a professor of preventive medicine at University of Southern California Keck School of Medicine who has specialized in the research of sexually transmitted diseases. 

“The organism changes its surface so that the antibiotic no longer recognizes it, or it starts to produce new enzymes that break down the antibiotic,” Klausner says. Gonorrhea, he says, has long been known as a bacteria that learns to evade antibiotics. 

Which STDs are causing the most concern?

Gonorrhea is far and away the most pressing concern. Currently, there’s only one CDC-recommended treatment for it: a combination of two powerful antibiotics, azithromycin and ceftriaxone.

Syphilis and chlamydia have also begun to show resistance to antibiotics in some parts of the world, though Klausner says there are several treatment options for both.

STDs, which don’t always have symptoms, can cause serious complications if left untreated:

• Gonorrhea can lead to pelvic inflammatory disease (PID), which causes inflammation of the ovaries, the fallopian tubes, and the uterus, which can ultimately lead to infertility. In men, it can cause infection of the testes and sterility. In rare cases, gonorrhea can spread to your blood or joints, which can be life-threatening. Untreated gonorrhea may increase your risk of HIV.
• Chlamydia can also cause PID in women, which may result in permanent damage. Though men seldom have long-term complications from untreated chlamydia, it can lead to sterility in rare cases.
• Syphilis, in its early stages, can cause chancre sores, rashes, fever, swollen lymph glands, and other symptoms. If left untreated for years, it can eventually damage the brain, heart, liver, and other organs, causing paralysis, numbness, blindness, dementia, and death.

Pregnant women with untreated STDs have a higher chance of stillbirth and newborn death, according to the World Health Organization. STDs can also affect babies during delivery.

Can these STDs still be treated?

As of 2020, the CDC recommends an injection of ceftriaxone for uncomplicated cases of gonorrhea.

Syphilis can be treated with penicillin, but Klausner says there have been shortages of the antibiotic in the United States and around the world. It can also be treated with azithromycin, though it has shown some resistance to this antibiotic, he says.

Chlamydia still responds to several antibiotics, including doxycyclin, erythromycin, amoxicillin, and azithromycin. Nevertheless, public health officials must be vigilant, says Englund.

“Any time you see resistance rising [in one STD], you need to look at the others for potential rise and make sure it doesn’t start to develop there as well,” she says.

How common are these STDs in general? How common are the antibiotic-resistant cases?

The CDC estimates there are 820,000 cases of gonorrhea in the United States each year. Klausner says that less than 1% fail to respond to the currently recommended treatment. However, he says, resistance to older, less expensive antibiotics is much higher.

Chlamydia is the most common STD in the United States, with nearly 3 million cases occurring annually. So far, no treatment-resistant cases have been reported.

In 2019, nearly 130,000 cases of syphilis were reported in the U.S., with the most infectious types increasing 11% from 2018 to 2019, according to CDC statistics. 

The numbers for these three STDs, which are the most common, are at a record high, according to the CDC.

“We’re absolutely seeing an increase in overall rates of STDs, particularly in younger patients,” says Englund. “Half of cases are diagnosed in patients aged 15 to 24.”

What can be done to address the problem?

Klausner says a three-way approach is needed:

• Control the spread of new infections through prevention, screening, and treatment. However, there is much less funding for such efforts. The CDC says that more than half of state and local STD programs have seen budget cuts in years. “The money taken out of budgets absolutely correlates with the increases in cases of STDs that we’re seeing,” Englund says.
• Develop new antibiotics. There’s good news here: A new antibiotic now being tested has shown promising results in recent trials. When and if it will be effective and enter the market is unknown.
• Develop tests to identify the best treatments. Klausner’s lab has developed a test, now in use at UCLA Health System, that can tell physicians which antibiotic a particular case of gonorrhea will respond to. This has allowed them to successfully treat many cases of gonorrhea with older, less expensive antibiotics.