Drug-resistant Shigella threatens young children globally

During their first two years of life, nearly 25% of children in low- and middle-income countries experience Shigella bacteria-caused diarrhea severe enough to warrant medical help. Most of these cases are resistant to recommended and commonly used antibiotics, a new global surveillance study found.

“We have known Shigella is a major contributor to childhood diarrhea since the use of more sensitive diagnostic tools in the last decade. But until this study, we did not appreciate the incredibly high burden of antibiotic resistance in this bacteria, limiting treatment options and threatening global health," said Patricia Pavlinac, one of the paper’s lead authors. She is an associate professor of global health, a joint department at the University of Washington School of Medicine and School of Public Health.

The findings were published March 11 in The Lancet Global Health.

Pavlinac said pathogens like Shigella are easily spread from person to person, including travelers, through contaminated food, water or surfaces. Because it is so contagious, its resistance to antibiotics makes it a global threat. 

Shigella bacteria cause shigellosis, an intestinal infection characterized by severe diarrhea, fever and stomach cramps. According to the World Health Organization, it is a leading bacterial cause of diarrhea worldwide, particularly in children under 5 in developing countries. Shigellosis is estimated to cause 100,000 deaths annually, mainly in young children.  

However, the risks are not limited to young children in developing countries. A documented shigellosis outbreak from 2017-2022 in Seattle was driven by multidrug-resistant strains involving international transmission and domestic transmission between at-risk populations. 

In the present study, nearly 10,000 children ages 6 months to 35 months with acute diarrhea were enrolled over two years across Bangladesh, Gambia, Kenya, Malawi, Mali, Pakistan and Peru. 

The effort used two lab methods, culture (growing bacteria) and DNA testing, to identify Shigella infections and to measure antibiotic resistance. 

The study authors stressed that, with increasing antibiotic resistance reducing the effectiveness of available treatments, the development of a vaccine that prevents infection is more important than ever. Shigella vaccines are being developed, with some nearing the point of large-scale trials to ensure safety and efficacy.

“This research is only the beginning,” Pavlinac said. “We must test future Shigella vaccine candidates, vigilantly monitor antibiotic resistance, and update treatment guidelines so shigellosis is treated with antibiotics to which it is susceptible.”

Pavlinac said substantial decreases in funding threaten vaccine research progress. This compounds the challenges of introducing a new vaccine amid a crowded early childhood vaccine schedule, overburdened healthcare systems and vaccine hesitancy. 

The study was funded by the Gates Foundation. 

Editor's note: *The subjects in the image at the top of this page gave consent to Paul J. Brown Photography to photograph them for non-commercial use. The image is used for illustrative purposes only. It does not imply any particular health status, attitudes, behavior or actions on the part of any person who appears in the photograph.

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