Oct 21, 2026
Drug-resistant Shigella, a highly contagious gut infection, is on the rise in the U.S. Extensively drug-resistant (XDR) cases climbed from 0% of tested samples in 2011–2015 to 8.5% in 2023, and this drug resistance can make empiric antibiotic choices unreliable.
As a result, antimicrobial susceptibility testing (AST) should guide treatment when antibiotics are needed. The good news: most Shigella infections clear on their own in 5 to 7 days without antibiotics.
What to do: If you have bloody diarrhea, a fever, or signs of dehydration, speak to a doctor. If you need a test, a provider can order a stool culture, or you can use an at-home molecular test such as Rapid GI or RectalKEY. If testing confirms you’re infected with Shigella, ask about antimicrobial susceptibility testing so any treatment is matched to the strain.
Wash your hands well, and don’t prepare food for others or have sex while you’re ill.
U.S. health officials at the Centers for Disease Control and Prevention (CDC) are tracking a concerning rise in Shigella infections that resist standard antibiotics. An April 2026 CDC Morbidity and Mortality Weekly Report found that the share of tested samples classified as extensively drug-resistant (XDR) rose from 0% in 2011–2015 to 8.5% in 2023.
A sample is classified as XDR if it is resistant to all five of these standard antibiotics: ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole.
Across 2011 to 2023, XDR strains made up 3% of about 16,800 samples, a figure the CDC says is likely an undercount since not every sample is tested for resistance.
Shigella causes shigellosis, a contagious gut infection that affects about 450,000 people in the U.S. each year. Most cases clear up naturally, but the increasing number of antimicrobial-resistant strains makes the infection harder to treat when treatment is needed.
Shigella is a group of bacteria that infects the intestines and causes shigellosis, also called bacillary dysentery. It spreads through the fecal-oral route, meaning tiny, often invisible amounts of stool from an infected person reach another person’s mouth. It can also spread through sexual contact. It is highly contagious as swallowing even a small amount of Shigella bacteria can make you ill.
Historically, most U.S. cases affected children and were caused by strains that responded to regular antibiotics. However, most drug-resistant cases the CDC identified occurred in adults (median age 41). Resistance genes can also spread to other gut bacteria, adding to the concern.
There are four species: Shigella sonnei, Shigella flexneri, Shigella boydii, and Shigella dysenteriae.
The CDC reports that XDR cases were driven by two of them: about two-thirds by S. sonnei (the most common species in the U.S.) and about one-third by S. flexneri, a larger share than its portion of infections overall.
S. boydii and S. dysenteriae are rare in the U.S., though S. dysenteriae is the species most often linked to a serious complication called HUS, described below.
Patients with shigellosis usually start to have symptoms 1 to 2 days after exposure and can include:
Shigellosis usually resolves in 5 to 7 days, though some people have symptoms for several weeks. Others have no symptoms but can still pass the Shigella bacteria to others.
See a healthcare provider if you have diarrhea with a fever, bloody or prolonged diarrhea, or severe stomach cramping or tenderness. Seek care sooner if you have a weakened immune system or are caring for a young child or older adult with a weakened or compromised immune system.
Bloody diarrhea deserves quick attention, partly because it can accompany hemolytic uremic syndrome (HUS). HUS is a rare complication where a bacterial toxin destroys red blood cells, which can lead to kidney failure.
The CDC links HUS to Shiga toxin-producing Shigella, usually S. dysenteriae. It most commonly affects children and can be deadly. Merck Manual states HUS usually appears about a week after symptoms start, sometimes up to 3 weeks later, often just as diarrhea is improving. Report new symptoms to your provider, even if you start feeling better.
The CDC lists these groups as higher risk: children under 5, international travelers, gay and bisexual men, people experiencing homelessness, and those with weakened immune systems. People in this last group can have symptoms for longer. Immune function can be weakened by conditions such as HIV or diabetes, or by the medicines taken after an organ transplant, all of which may raise the risk of more severe illness.
Anyone can get shigellosis, but resistant strains are concentrated in specific groups. In the CDC’s analysis, 86% of patients with XDR shigellosis were men; about 47% had HIV (among those with known HIV status); and about 38% were hospitalized—with no deaths reported. Most reported no international travel, which points to spread within the U.S., but travel data was missing for about half of patients.
Risk tied to sexual activity comes from contact with stool during sex. Anyone can lower their risk with the prevention steps below.
If you have symptoms, a provider can order a stool culture or a culture-independent test such as a molecular test like PCR, which detects a microbe by its DNA rather than growing it in a petri dish.
Molecular tests like MicroGenDX’s Rapid GI and RectalKEY can be more sensitive than culture, especially for people who have recently taken antibiotics, and can be easily collected at home. Both can also help tell apart E. coli and Shigella, which are genetically very similar, although RectalKEY cannot provide strain-level names.
However, a negative at-home result can’t rule out Shigella, and a positive result is often confirmed with a culture.
When a culture test is positive, providers can order antimicrobial susceptibility testing to find which antibiotics will work against that specific strain. With resistant strains on the rise, this step helps providers prescribe effective treatment and support antibiotic stewardship. Once all test results are in, your provider can choose an antibiotic that works against your strain, if you need one at all.
As you recover, drink plenty of fluids to prevent dehydration. If your diarrhea is bloody, it’s best to avoid anti-diarrheal medicines such as Imodium, which may worsen symptoms. Check with your provider before taking any over-the-counter remedy.
The CDC’s core prevention advice is careful handwashing and good hygiene:
This article is for general educational purposes and is not medical advice. If you are experiencing symptoms, consult a licensed healthcare provider.
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