CDC warns drug-resistant Shigella infections are rising in the US

The US Centers for Disease Control and Prevention (CDC) is reporting a rise in extensively drug-resistant (XDR) Shigella infections in the United States, according to an analysis of laboratory isolates collected between 2011 and 2023.

XDR Shigella is defined as resistant to five commonly used antibiotics: ampicillin, azithromycin, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole. The CDC also says there are currently no FDA-approved oral antibiotics available for XDR Shigella infections.

XDR strains rose to 8.5% of isolates in 2023 The CDC analyzed 16,788 Shigella isolates collected through PulseNet from 2011 to 2023. The proportion identified as XDR rose from 0% during 2011–2015 to 8.5% in 2023.

Who is being affected has shifted The CDC report indicates the epidemiology has changed compared with prior US outbreaks, which were largely drug-susceptible and primarily affected children. In contrast, XDR Shigella cases have mostly occurred in adult males, with an average age of 41.

Travel history data suggest most cases are acquired domestically. Among people with available data, 76.2% reported no recent domestic travel and 82.4% reported no recent international travel.

Limited treatment options Because antibiotic options are limited for XDR Shigella, treatment may rely on supportive care. For severe infections requiring hospitalization, intravenous carbapenems are described as a reliable option.

The CDC said stronger surveillance, routine antimicrobial susceptibility testing, and timely reporting are needed, along with targeted prevention measures to reduce further spread.