U.S. Sees Surge in XDR Shigella: 8.5% of Isolates Resistant in 2023

Imagine a common stomach bug that no longer responds to frontline antibiotics. That’s the alarming reality taking shape across America, as the Centers for Disease Control and Prevention (CDC) have confirmed that 8.5% of Shigella isolates in 2023 were extensively drug resistant (XDR). The rise from zero percent in 2011-15 to nearly one in twelve cases is rewriting the rules of how we fight bacterial infections.

What Exactly is XDR Shigella?

Shigella is a bacterial pathogen usually associated with diarrhea, stomach cramps, fever, and possibly blood in the stool. Most people recover without medical intervention. But extensively drug-resistant Shigella refers to strains immune to all five commonly used antibiotics: ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. When bacteria cross that line, typical oral treatment options vanish.

Data Trends: From Rare to Rising Fast

The CDC’s latest surveillance, collected through its PulseNet system, analyzed roughly 16,800 Shigella isolates submitted between 2011 and October 2023. In that group, XDR strains grew from non-existent during 2011-2015 to a worrying 8.5% in 2023. That jump underscores a rapid acceleration in resistance. While over 500 isolates in total were classified as XDR, none resisted meropenem or fosfomycin—showing some treatment avenues are still intact.

Who’s Being Hit—and Where Transmission Is Occurring

Unlike earlier outbreaks that mostly struck young children, recent XDR cases in the U.S. overwhelmingly involve adult men. Of the 492 cases with age and sex data, 86% were males aged 18 or older, with a median age of 41. Children under 18 made up under 4% of reported cases. Shigella sonnei causes most of these infections, though Shigella flexneri is nearly doubling its share among XDR strains compared with historical levels.

Most infections are now happening domestically. Over three-quarters of patients reported no recent travel inside or outside the U.S. That shifts the narrative: XDR Shigella is no longer an imported threat—it has become entrenched locally. Key groups facing higher risk include men who have sex with men (MSM), particularly those with HIV or compromised immune systems, people experiencing homelessness, and international travelers.

What This Means for Treatment and Prevention

Treatment options for XDR Shigella are sharply limited. There are currently no FDA-approved oral antibiotics

Preventing spread becomes critical. Methods include strict handwashing, safely preparing food, and staying home while sick. Healthcare providers are being urged to run antimicrobial susceptibility tests (AST) whenever Shigella is identified, treating only when necessary. Local and state health departments must be alerted about suspected XDR cases, especially among people in high-risk groups. Real-time genomic surveillance is increasingly seen as a must—several recent clusters, including ones in California, have been tracked via whole-genome sequencing, revealing shared resistance genes like CTX-M-15 among nearby cases.