A new, extensively drug-resistant (XDR) strain of Shigella bacteria has been identified in Los Angeles, raising concerns about its potential spread. Researchers at the University of California, Los Angeles (UCLA) discovered the strain while investigating a cluster of cases between 2023 and 2024. While all affected individuals recovered, the emergence of this superbug poses a significant threat, especially to vulnerable populations.
Shigella is a common cause of diarrhea and gastrointestinal distress. Most infections resolve within a week without treatment, but severe complications can occur, particularly in young children or those with weakened immune systems. Globally, Shigella is responsible for approximately 200,000 deaths annually. In the United States, it’s estimated to cause half a million illnesses and thousands of hospitalizations each year. Transmission typically occurs through contaminated food or drink, but sexual transmission, especially through anal contact among men who have sex with men, is also possible.
Antibiotics are crucial for treating severe Shigella infections or managing infections in high-risk individuals. However, like many bacteria, Shigella has developed resistance to commonly used antibiotics. XDR strains, resistant to a broad spectrum of antibiotics, are the most worrisome. The UCLA study, published in the Journal of Infection Control, details the identification of a novel XDR Shigella sonnei strain in three patients.
The three cases, identified within a three-month period between 2023 and 2024, involved men who have sex with men. One patient reported a recent sexual partner diagnosed with Shigella. Lab tests confirmed the presence of an XDR strain resistant to azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole, and ampicillin.
Genetic analysis revealed a distinct strain, suggesting it has been evolving and circulating locally. While all three patients recovered, one experienced a severe infection requiring intensive care. Real-time detection of the XDR resistance allowed doctors to switch to an effective alternative antibiotic.
The rise of XDR Shigella is a growing public health concern. These infections are challenging to treat, and delays in finding effective antibiotics can be life-threatening. The Centers for Disease Control and Prevention (CDC) issued a health advisory in 2022, reporting a significant increase in XDR Shigella cases. The UCLA researchers emphasize the need for enhanced detection and management strategies.
This discovery underscores the urgent need for increased surveillance, rapid diagnostics, and development of new treatments to combat the spread of this dangerous superbug. Early detection and appropriate antibiotic stewardship are critical to prevent severe outcomes and limit further transmission.
