The proportion of extensively drug-resistant Shigella infections in the United States climbed from zero percent between 2011 and 2015 to 8.5 percent in 2023, according to a new CDC report. Of 16,788 bacterial isolates analyzed, 510 were classified as extensively drug-resistant, or XDR.
Shigella causes shigellosis, a diarrheal illness that sickens roughly a million Americans each year. The XDR strains resist five commonly used antibiotics, and the CDC noted that no oral antibiotics currently approved by the FDA are available to treat them. That gap in treatment options makes the rising case count especially concerning for public health officials.
The profile of who gets infected has changed significantly. Earlier U.S. outbreaks involved drug-susceptible strains and primarily affected children. XDR Shigella cases have shifted toward adult males with an average age of 41. Most infections were acquired domestically: among those with available data, 76.2 percent reported no recent domestic travel and 82.4 percent reported no recent international travel.
Shigella spreads easily. The bacteria appear in feces, and swallowing even a small amount can cause illness. Transmission routes include contaminated food or water, direct contact with someone who is sick or recently recovered, and sexual contact. The low infectious dose makes community spread particularly difficult to contain.
William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University School of Medicine, told Healthline that antibiotic resistance is a global problem driven by overuse and misuse of antibiotics worldwide. "In the U.S., clinicians and public health have worked hard to become good stewards of antibiotics, using them carefully," he said.
The CDC called for stronger surveillance in response to the findings, along with routine antimicrobial susceptibility testing and timely reporting of shigellosis cases. Because shigellosis is a nationally notifiable disease, health departments are required to report confirmed cases to federal authorities. The agency also called for targeted prevention efforts to slow the spread of XDR strains.
Regular handwashing remains one of the most effective tools available to the general public for reducing transmission. The CDC also recommends avoiding food prepared by someone who is sick, refraining from sexual activity with anyone who has an active or recent infection, and being cautious about water sources when the safety is uncertain.
