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Updated: Jun 20, 2025
Author Spotlight: Advancements in Understanding and Combatting Shigella Infections
Published on: February 9, 2024
Multidrug-resistant Shigella flexneri outbreak associated with a high-mortality spillover event into nonhuman
Daryl Domman1, Sarah Shrum Davis2, Paris Salazar-Hamm3
1University of New Mexico Health Sciences Center.
Abstract:
Shigellosis is a gastrointestinal infection caused by species of Shigella. A large outbreak of Shigella flexneri serotype 2a occurred in Albuquerque, New Mexico (NM) between May 2021 and November 2023 that involved humans and nonhuman primates (NHP) from a local zoo. We analyzed the genomes of 202 New Mexico isolates as well as 15 closely related isolates from other states, and four from NHP. The outbreak was initially detected within men who have sex with men (MSM) but then predominantly affected people experiencing homelessness (PEH). Nearly 70% of cases were hospitalized and there was one human death. The outbreak extended into Albuquerque's BioPark Zoo, causing high morbidity and six deaths in NHPs. The NHP isolates were identical to those in the human outbreak. All isolates were multidrug-resistant, including towards fluoroquinolones, a first line treatment option which led to treatment failures in human and NHP populations. We demonstrate the transmission of this S. flexneri strain between humans and NHPs, causing fatalities in both populations. This study demonstrates the threat of antimicrobial resistant organisms to vulnerable human and primate populations and emphasizes the value of vigilant genomic surveillance within a One Health framework.
Insights
A multidrug-resistant Shigella flexneri strain caused a deadly outbreak in humans and nonhuman primates in New Mexico. Genomic surveillance revealed transmission between populations, highlighting the threat of antimicrobial resistance.
Area of Science:
- Microbiology
- Genomics
- Epidemiology
Background:
- Shigellosis, a gastrointestinal infection, is caused by Shigella species.
- A significant outbreak of Shigella flexneri serotype 2a occurred in Albuquerque, New Mexico, spanning May 2021 to November 2023.
- The outbreak involved both human populations and nonhuman primates (NHP) from a local zoo.
Purpose of the Study:
- To analyze the genomic epidemiology of a Shigella flexneri 2a outbreak.
- To investigate the transmission dynamics between human and NHP populations.
- To assess the antimicrobial resistance patterns of the outbreak isolates.
Main Methods:
- Whole-genome sequencing of 202 human and 4 NHP Shigella flexneri isolates from New Mexico.
- Analysis of 15 related isolates from other states.
- Genomic comparison to identify strain identity and transmission links.
Main Results:
- The outbreak involved a multidrug-resistant Shigella flexneri 2a strain, identical in human and NHP isolates.
- Transmission was observed between humans and NHPs, resulting in high morbidity and mortality in both.
- Human cases predominantly affected people experiencing homelessness (PEH) after initial detection in men who have sex with men (MSM).
- Nearly 70% of human cases required hospitalization, with one fatality.
- Six NHP deaths were recorded at the zoo.
Conclusions:
- The study demonstrates interspecies transmission of a multidrug-resistant Shigella flexneri strain between humans and NHPs.
- Antimicrobial resistance poses a significant threat to vulnerable human and primate populations.
- Genomic surveillance within a One Health framework is crucial for detecting and managing such outbreaks.
