The Centers for Disease Control and Prevention (CDC) in a health advisory today reported on an increase in extensively drug-resistant (XDR) Shigella infections (shigellosis) reported through national surveillance systems.


In the United States, the percentage of Shigella infections caused by XDR strains reported to CDC increased from zero in 2015 to 5% in 2022. Between January 1, 2015, and January 22, 2023, CDC received reports of 239 XDR Shigella isolates, with Shigella sonnei accounting for the largest percentage (66%) followed by Shigella flexneri (34%).

The median age of patients was 42 years (range 1–83 years). Among 232 patients with available information, 82% were men, 13% were women, and 5% were children. Among 41 patients who answered questions about recent sexual activity, 88% reported male-to-male sexual contact.

Clinicians treating patients infected with XDR strains have limited antimicrobial treatment options.
Shigella bacteria are easily transmissible. XDR Shigella strains can spread antimicrobial resistance genes
to other enteric bacteria. Given these potentially serious public health concerns, CDC asks healthcare
professionals to be vigilant about suspecting and reporting cases of XDR Shigella infection to their local
or state health department and educating patients and communities at increased risk about prevention
and transmission.

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Shigellosis is an acute enteric infection that is an important cause of domestically acquired and travel associated bacterial diarrhea in the United States. Shigellosis usually causes inflammatory diarrhea that can be bloody and may also lead to fever, abdominal cramping, and tenesmus. Infections are generally self-limiting; however, antimicrobial treatment may be indicated to prevent complications or shorten the duration of illness. CDC defines XDR Shigella bacteria as strains that are resistant to all commonly recommended empiric and alternative antibiotics — azithromycin, ciprofloxacin, ceftriaxone, trimethoprimsulfamethoxazole (TMP-SMX), and ampicillin.

Currently, there are no data from clinical studies of treatment of XDR Shigella to inform recommendations for the optimal antimicrobial treatment of these infections. As such, CDC does not have recommendations for optimal antimicrobial treatment of XDR Shigella infections.