The Centers for Disease Control and Prevention reported that a sexually transmitted diarrhea outbreak involving Shigella infections in the United States grew more resistant in 2023. The agency said 8.5% of isolates were extensively drug-resistant that year, and most documented cases were in adults.
That matters because the 510 extensively drug-resistant isolates in the CDC analysis could resist ampicillin, azithromycin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole. The agency reviewed nearly 17,000 Shigella isolates collected from 2011 through Oct. 20, 2023.
CDC isolate data
Among the 16,788 isolates with resistance data, 510 were classified as extensively drug-resistant. The share rose from 0% between 2011 and 2015 to 8.5% in 2023, and most of the drug-resistant cases were reported in 2022 and 2023.
Of the 258 patients with hospitalization information, 97 were hospitalized. No deaths were reported. Nearly 96% of patients with available age and sex information were at least 18 years old, 86.2% were men, and the median age was 41.
Shigella spread routes
Shigella can spread through fecal-oral contact, contaminated food or water and sexual contact, and infection can occur after exposure to as few as 10 organisms. The CDC said sexual exposure information was incomplete and was not analyzed, even though previous studies have identified sexual contact among men who have sex with men as an important transmission route.
That leaves clinicians with a narrower treatment path when resistance is present. Health officials urged providers to order antimicrobial susceptibility testing when possible and to report cases promptly, especially because people with weakened immune systems, including those living with HIV, may face a higher risk of severe illness and fewer treatment options.
CDC testing advice
The CDC said the study likely underestimated the number of extensively drug-resistant infections because not all Shigella-positive specimens were cultured or genetically sequenced. Of the patients with available information, 76.2% reported no recent domestic travel and 82.4% reported no recent international travel, which points back to domestic spread in many documented cases.
For readers who may be affected, the practical step is straightforward: ask for testing when treatment is being considered and make sure any suspected case reaches public health reporting channels quickly. Which specific transmission settings are driving the rise is still not answered.
