CDC: drug-resistant Shigella cases jumped from 0% to 8.5% with no oral treatment available.
A drug-resistant bacterial infection linked to diarrhea is becoming harder to treat and more common across the United States, federal health officials warned in a new report released April 9.
The Centers for Disease Control and Prevention found that an extensively drug-resistant form of Shigella, referred to as XDR Shigella, went from representing 0% of cases between 2011 and 2015 to 8.5% of cases by 2023. With roughly 450,000 Shigella infections occurring in the US each year, that figure translates to more than 36,000 Americans potentially dealing with a strain that standard antibiotics cannot touch.
There is currently no FDA-approved oral treatment for XDR Shigella infections.
What makes this Shigella strain so difficult to treat
The XDR strain resists five commonly prescribed antibiotics: ampicillin, azithromycin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole. These are the same medications that historically cleared up Shigella infections quickly. Their failure against the XDR form leaves both patients and clinicians with far fewer tools to work with.
Officials analyzed more than 16,700 Shigella samples collected between January 2011 and October 2023. The first drug-resistant case appeared in 2016, and the numbers have climbed steadily since. Over a third of patients diagnosed with the XDR strain were hospitalized.
Who is getting infected and how Shigella spreads
The shift in who gets infected is one of the more notable findings in the report. Historically, Shigella was a disease that primarily struck children under five years old. The latest data tells a different story. Most cases of XDR Shigella are now occurring in adult men, with a median age of 41. Among those who shared travel history, 82.4% reported no recent international travel, meaning the spread is largely domestic.
Shigella passes easily from person to person through fecal-oral transmission, sexual contact or contaminated food and water. The CDC has identified sexual contact among men who have sex with men as a significant transmission route. Co-infections with other sexually transmitted bacterial infections have also been reported. People living with HIV face additional risk, given already limited treatment options and a higher likelihood of severe illness.
Symptoms and when to seek care
Symptoms of a Shigella infection typically appear within one to two days of exposure and include diarrhea that may be bloody or last more than three days, fever and stomach pain. Most cases resolve within five to seven days, though some stretch longer.
People with weakened immune systems, persistent high fever, frequent vomiting, bloody diarrhea or signs of dehydration should contact a doctor. Children, travelers, people experiencing homelessness and those who engage in anal sex face higher risk of infection.
How to reduce the risk of infection
The CDC recommends washing hands thoroughly and regularly, avoiding swallowing water while swimming, following food and water safety precautions when traveling and abstaining from sex for at least two weeks after symptoms clear up if infected.
Prevention and early detection remain the most effective tools available. As the report put it, stronger surveillance, faster reporting and targeted prevention strategies are what will ultimately limit how far XDR Shigella spreads. Without those measures in place, a strain that was virtually nonexistent just over a decade ago could become a lasting fixture in the US infectious disease landscape.