Extensively drug-resistant Shigella – the mostly sexually-transmitted bacterium that causes infectious diarrhoea – is on the rise in the United States, reports Healio.
The latest data from the CDC’s Morbidity and Mortality Weekly Report (MMWR) found that among nearly 17 000 Shigella isolates submitted to a CDC surveillance network, the proportion of extensively drug-resistant (XDR) isolates rose from 0% in 2011 to 8.5% in 2023. Around one-third of patients with XDR Shigella ended up in hospital.
XDR Shigella spreads easily from person-to-person through faecal-oral contact or sexual activity. The report cited prior studies that identify men who have sex with men as a “transmission route” for Shigella while also noting that of the 116 patients infected with XDR shigellosis with HIV status information, 54 (46.6%) had HIV.
The study also noted that of the 492 patients with XDR shigellosis and available sex and age information, median age was 41 years. And of the 473 patients aged at least 18, 86.2% were men.
Jason Zucker, MD, assistant Professor of Medicine at Columbia University Medical Centre, told Healio he frequently sees Shigella cases come through his group’s sexual health clinic.
“Anecdotally,” he said, “it does seem that more are resistant to antibiotics, though I don’t have hard data on that from our clinic specifically.”
Zucker, who was not part of the CDC study, said it was important to educate, not shame, people about Shigella as an STI.
“The starting point is recognising that the sexual practices that can transmit Shigella are common and normal,” Zucker said. “Effective education means integrating Shigella into the same conversations we already have about STI prevention.”
In the study, oral carbapenems, pivmecillinam and fosfomycin are mentioned as possible treatments for XDR shigellosis, although none has been approved by the FDA for this indication.
“Treatment of XDR shigellosis remains challenging because no optimal therapy has been established,” the report added.
Common symptoms include diarrhoea, fever, stomach pain and experiencing a feeling to pass stool when bowels are empty.
Zucker said most shigellosis cases will resolve on their own, but that the rise of XDR Shigella “should prompt a broader conversation about sexual health, make sure the patient is up-to-date on STI screening, discuss (pre-exposure prophylaxis) if they’re not already on it and assess whether they’re connected to HIV prevention or care”.
Study details
Emergence of Extensively Drug-Resistant Shigellosis – US, 2011–2023
Naeemah Logan, Meseret Birhane, Sharla McDonald et al.
Published in MMWR on 9 April 2026
Abstract
Shigellosis is a nationally notifiable diarrhoeal illness caused by gram-negative bacteria. Shigella infection is spread through faecal-oral transmission and sexual contact. Although most infections are self-limited, antibiotics are indicated for severe illness or to reduce transmission in settings with high risk for spread. Since 2015, a growing proportion of cases has been caused by extensively drug-resistant (XDR) Shigella species, defined as being resistant to ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. No Food and Drug Administration–approved oral antimicrobial agents are available to treat these XDR infections. To describe US trends and epidemiologic characteristics of XDR shigellosis, CDC analysed Shigella isolates submitted to PulseNet, CDC’s molecular surveillance network for enteric pathogens, during January 1, 2011–October 20, 2023; antimicrobial resistance was characterised using whole-genome sequencing data and antimicrobial susceptibility testing. Among 16 788 isolates with resistance data during this period, 510 (3.0%) were XDR. The percentage of XDR isolates increased from 0% during 2011–2015 to 8.5% in 2023. Species information was available for 505 (99%) of 510 XDR isolates; among those, 333 (65.9%) were Shigella sonnei and 172 (34.1%) were Shigella flexneri. Among patients with XDR shigellosis, the median patient age was 41 (IQR = 31–54 years) and 86.2% were men. Among patients with available travel history, 76.2% (173 of 227) reported no recent domestic travel and 82.4% (169 of 205) reported no recent international travel. Among 116 persons with available HIV status, 54 (46.6%) reported HIV co-infection. Strengthened surveillance, timely reporting, and targeted prevention strategies are needed to limit transmission of XDR Shigella strains.
Healio article – Extensively drug-resistant Shigella on rise in US (Open access)
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CDC warning about drug-resistant Shigella
WHO lists top endemic pathogens urgently needing new vaccines
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