By Kiara Doyal, The Seattle Medium
A new study from the University of Washington School of Medicine finds that one in four children in low- and middle-income countries experiences Shigella-related diarrhea severe enough to require medical care within their first two years of life, with many of those infections resistant to commonly recommended antibiotics.
Researchers say the findings highlight a growing global health threat as antibiotic resistance limits treatment options for one of the leading causes of childhood diarrhea.
“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 and an associate professor of global health at the University of Washington.
Shigella bacteria causes 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 among children under 5 in developing countries, and is linked to an estimated 100,000 deaths each year.
Pavlinac said that while global efforts have helped reduce deaths from diarrheal diseases, the overall burden remains significant, particularly due to long-term health impacts.
“Failure to reach full growth potential and chronic inflammation in the gut leading to poor response to vaccines, have remained stable. These consequences are more common in pathogens like Shigella which invade the walls of the intestine wreaking havoc on the gut,” said Pavlinac.
The study also found that antibiotic resistance is increasing, making infections harder to treat and raising concerns among public health experts.
“In parallel, in places like Seattle where there is diagnostic capacity to monitoring Shigella and its response to specific antibiotics, it’s being documented that Shigella is rapidly developing resistance to the antibiotics we use,” said Pavlinac.
Because Shigella spreads easily through contaminated food, water and surfaces, as well as person-to-person contact, its growing resistance to treatment poses a broader global risk.
“It was for these reasons that we were motivated to conduct the Enterics for Global Health Study to document the burden of Shigella,” said Pavlinac.
With nearly 25 percent of young children in low- and middle-income countries affected, Pavlinac said prevention is one of the most urgent public health priorities.
“Of course, the first priority should be prevention, ideally by safe water and sanitation to reduce transmission of Shigella and to reduce its presence in the environment. However, sanitation improvements take political will, financing and large-scale programs that guarantee a long runway until settings like those included in our study will have universally available safe water and sanitation,” said Pavlinac.
Vaccination is another critical area of focus, though progress has been slow due to limited funding.
“Vaccination is critical and Shigella vaccine development was stalled for decades after initial work in the 1990’s due to lack of funding,” said Pavlinac.
She said recent developments offer some hope, including a vaccine currently being tested in a Phase 3 trial in Bangladesh, though access and affordability remain concerns.
“I think vaccine development timelines are certainly more realistic than timelines for resolving water and sanitation issues. For example, there is already a bi-valent shigella vaccine being tested in a Phase 3 trial in Bangladesh. However, getting a vaccine developed and licensed is only half the battle,” said Pavlinac. “Unprecedented funding cuts to international organizations such as the Global Alliance for Vaccines and Immunizations which facilitate vaccine availability and affordability in countries that need them most, means most countries are unlikely to be able to afford a Shigella vaccine even if its developed and there is a need.”
Shigellosis outbreaks have also occurred in Seattle, where certain populations face higher risk.
“In Seattle, the populations at risk are travelers to Shigella endemic settings, children in daycare settings, and adults engaging in anal intercourse because of risk of fecal-oral transmission,” said Pavlinac. “We are lucky in Seattle to have clinical microbiology labs doing routine monitoring of Shigella infections and antibiotic resistance and have access to a wide array of antibiotics and international experts in treating infectious diseases.”
Pavlinac said the findings underscore the need for both global and local action to address the spread of antibiotic-resistant infections.
“It increases the urgency for prevention of Shigella infections. Enteric diseases like shigellosis are historically under-funded and under-appreciated because the highest burden is among children in lower-resourced settings, a population without a platform to increase awareness and advocacy about the importance of these deadly diarrheal diseases,” said Pavlinac. “Our data makes it undeniable that antibiotic resistant shigella is a worldwide problem, and one that poses harm not only to children, but universally.”
As antibiotic resistance continues to rise, researchers warn that without significant investment in prevention, treatment and vaccine development, infections like Shigella could become increasingly difficult to control, particularly in the communities most at risk.
