It starts like a bad stomach bug: cramps, fever and diarrhea that won’t let up, sometimes with blood. Most people recover within a week. But a growing share of cases now involve a strain of bacteria that common antibiotics can no longer touch, and doctors say it’s increasingly spreading through sexual contact rather than contaminated food or water.
Key Takeaways
- Shigella is a highly contagious bacterial infection that causes diarrhea, fever and stomach cramps. It sickens an estimated 450,000 Americans a year.
- “Extensively drug-resistant” (XDR) strains rose from 0% of tested U.S. samples in 2011–2015 to 8.5% in 2023, according to a CDC report published in April 2026. These strains resist all five antibiotics commonly used to treat it.
- Most XDR cases were in adult men, many of whom hadn’t traveled abroad, which points to spread within the U.S. Research has identified sexual contact, especially among men who have sex with men, as a key route.
- More than a third of people with XDR shigella were hospitalized, though no deaths were reported in the CDC data.
- Prevention is simple: wash hands with soap, avoid sex and food preparation while sick and for two weeks after recovering, and tell your doctor about recent sexual contact if you develop dysentery.
What’s happening
The CDC analyzed nearly 17,000 shigella samples submitted to its national lab surveillance network from 2011 to late 2023. Of those with resistance data, 510 were extensively drug-resistant, meaning the bacteria resisted ampicillin, azithromycin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole, the antibiotics doctors normally reach for. More than 80% of those XDR cases were reported in just 2022 and 2023.
The patients looked very different from shigella’s traditional profile. Shigella has long been associated with outbreaks among young children in daycare. But 86% of the XDR patients were men, with a median age of 41, and most reported no recent travel. Of those with known HIV status, nearly half were living with HIV, which can raise the risk of severe illness. The CDC says the true number is likely higher, because not every positive stool test is cultured or sequenced.
The U.S. is not alone. A genomic study from the University of Cambridge and the UK Health Security Agency, published in The Lancet Infectious Diseases in July 2026, found that sexually transmitted shigella strains in England were spreading faster than strains linked to travel or food. More than 70% of them were resistant to at least one key antibiotic. The researchers estimate that more than half of UK shigella infections are now sexually transmitted. They warned the infection is becoming close to untreatable with standard drugs.
How it spreads and why resistance is growing
Shigella spreads through tiny amounts of infected stool, as few as 10 bacteria can cause illness. That can happen through unwashed hands, contaminated food or water, close contact in households and childcare settings, or sexual activity that involves contact with the anal area.
Researchers suspect resistance is rising in part because people in some sexual networks receive repeated antibiotic courses for other sexually transmitted infections, such as gonorrhea. That exposure can push shigella bacteria in the gut to become resistant too. The UK researchers found that resistant strains spread significantly faster than drug-susceptible ones.
Symptoms and treatment
Symptoms usually start one to two days after exposure and can include:
- Diarrhea, sometimes bloody
- Fever
- Stomach pain and cramping
- Feeling the need to pass stool even when the bowels are empty
Most healthy people recover in five to seven days without antibiotics. Drinking plenty of fluids is key, and oral rehydration solutions can help. Avoid anti-diarrheal medicines unless a doctor approves, since they can make some infections worse.
See a doctor if you have bloody diarrhea, a high fever, signs of dehydration (very little urine, dizziness, dry mouth), or symptoms that last more than a few days, especially if you’re older, have a weakened immune system or are living with HIV. If you need treatment, doctors may order lab testing to find out which antibiotic will work, since XDR strains don’t respond to the usual options. There’s currently no FDA-approved oral antibiotic specifically for XDR shigella.
How to protect yourself and others
- Wash your hands with soap and water after using the bathroom, changing diapers and before handling food.
- Don’t prepare food for others while you’re sick.
- Avoid sex while you have diarrhea and for two weeks after you feel better, since you can still pass the bacteria on.
- Use barriers such as condoms or dental dams during oral and anal sex, and wash before and after sex.
- Be open with your doctor. If you develop dysentery, mention any recent sexual contact so they can test appropriately and check for other sexually transmitted infections.
This isn’t a substitute for medical advice. Talk to your doctor if you have symptoms or concerns.
Sources:
- CDC. Emergence of extensively drug-resistant shigellosis — United States, 2011–2023. Morbidity and Mortality Weekly Report, April 9, 2026.
- Marshall J, Baker KS, et al. The spread of sexually transmissible drug-resistant shigellosis in England: a genomic epidemiology study. The Lancet Infectious Diseases, July 2026.
- University of Cambridge. Sexually transmitted diarrhoea spreading rapidly among some networks of gay men in the UK, study finds. July 9, 2026.