The Centers for Disease Control and Prevention reported that shigellosis caused by extensively drug-resistant Shigella rose in the United States, reaching 8.5% of isolates in 2023. The report covers nearly 17,000 isolates collected from 2011 through Oct. 20, 2023.
Among 16,788 isolates with resistance data, 510 were classified as extensively drug-resistant. Those isolates were resistant to ampicillin, azithromycin, ceftriaxone, ciprofloxacin and trimethoprim-sulfamethoxazole.
CDC isolate data
The percentage of isolates classified as extensively drug-resistant rose from 0% between 2011 and 2015 to 8.5% in 2023. Most of the drug-resistant cases were reported in 2022 and 2023, making the recent increase the sharpest part of the trend.
The CDC said it likely underestimated the number of extensively drug-resistant infections because not all Shigella-positive specimens were cultured or genetically sequenced. That limits how completely the collected samples capture the full burden in the United States.
Hospitalizations and travel
Of 258 patients with available hospitalization information, 97 were hospitalized, and no deaths were reported. Of the patients with available information, 76.2% reported no recent domestic travel and 82.4% reported no recent international travel, suggesting many infections were acquired within the United States.
Shigella can cause diarrhea, fever and stomach pain, and infection can occur after exposure to as few as 10 organisms. The CDC said people with weakened immune systems, including those living with HIV, may face a higher risk of severe illness and fewer treatment options.
Transmission details
Shigella spreads through fecal-oral contact, contaminated food or water and sexual contact, but sexual exposure information was incomplete and was not analyzed in this report. The CDC said previous studies identified sexual contact among men who have sex with men as an important transmission route.
Health officials urged clinicians to order antimicrobial susceptibility testing when possible and to report cases promptly, since the resistant isolates were already known to be resistant to five common antibiotics. For patients and clinicians, that leaves faster testing and quicker reporting as the practical next step when shigellosis is suspected.
