The Centers for Disease Control and Prevention said extensively drug-resistant shigellosis increased in the United States and reached 8.5% of Shigella isolates in 2023, a jump that narrows treatment choices for an infection that can spread with very few organisms.
The finding comes from a CDC review of nearly 17,000 Shigella isolates collected from 2011 through Oct. 20, 2023. Of the 16,788 isolates with resistance data, 510 were classified as extensively drug-resistant, meaning they resisted ampicillin, azithromycin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole. The share was 0% from 2011 through 2015, then climbed to 8.5% in 2023.
The increase matters because no Food and Drug Administration-approved oral antibiotics are specifically available to treat extensively drug-resistant Shigella infections. When that happens, clinicians have to lean on antimicrobial susceptibility testing to see what, if anything, still works against an individual isolate rather than relying on a standard oral option. The CDC also said most of the drug-resistant cases appeared in 2022 and 2023, with 415 cases reported during those two years.
Most of the patients for whom age and sex were available were adults, and 86.2% were men, with a median age of 41. Of the 258 patients with hospitalization information, 97 were hospitalized. No deaths were reported. HIV status was available for only 116 patients, and 54 of them reported an HIV co-infection.
That picture still likely understates how many infections are out there. Sexual exposure information was incomplete and was not analyzed, and the CDC said the study likely underestimated the number of extensively drug-resistant infections. Reporting and testing practices also varied by state and local jurisdiction, which makes the trend harder to pin down with precision.
Shigella spreads through fecal-oral contact, contaminated food or water and sexual contact, and prior studies have identified sexual contact among men who have sex with men as an important transmission route. The CDC said people with weakened immune systems, including those living with HIV, may face a higher risk of severe illness and have fewer treatment options. Most patients did not report recent travel, suggesting many infections were acquired within the United States.
The next step is straightforward and difficult at once: test more, report faster and match treatment to susceptibility results whenever possible. The rise to 8.5% in 2023 shows that shigellosis is becoming harder to treat just as the pool of usable oral options is shrinking.
