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Updated: Apr 27, 2026
A High-throughput Shigella-specific Bactericidal Assay
Published on: February 27, 2019
Shigella isolates from the global enteric multicenter study inform vaccine development
Sofie Livio1, Nancy A Strockbine2, Sandra Panchalingam1
1Center for Vaccine Development, University of Maryland School of Medicine, Baltimore.
Insights
Shigella, a leading cause of diarrhea, necessitates vaccine development. A quadrivalent vaccine targeting common Shigella sonnei and Shigella flexneri serotypes offers broad protection against this global pathogen.
Area of Science:
- Infectious Diseases
- Vaccinology
- Microbiology
Background:
- Shigella is a major global pathogen causing diarrheal disease, prompting vaccine development efforts.
- The Global Enteric Multicenter Study (GEMS) assessed the burden and causes of moderate-to-severe diarrhea in children across Africa and Asia.
- Shigella was identified as one of the four most prevalent pathogens in the GEMS study.
Purpose of the Study:
- To review Shigella serotypes identified in the GEMS study to inform vaccine development.
- To determine the most prevalent Shigella serotypes responsible for diarrheal disease in young children.
Main Methods:
- Stool specimens were collected from children with diarrhea and controls.
- Shigella isolates were identified using selective agar plating, biochemical tests, and serological agglutination.
- Isolates were confirmed and serotyped at a reference laboratory, with external quality control.
Main Results:
- Shigella dysenteriae and S. boydii accounted for approximately 5% each of 1130 Shigella cases.
- Shigella flexneri (65.9%) and S. sonnei (23.7%) were the predominant species.
- Five S. flexneri serotypes/subserotypes (2a, 6, 3a, 2b, 1b) constituted 89.4% of S. flexneri isolates.
Conclusions:
- A comprehensive Shigella vaccine should target S. sonnei and 15 S. flexneri serotypes/subserotypes.
- A quadrivalent vaccine incorporating O antigens from S. sonnei, S. flexneri 2a, 3a, and 6 offers substantial direct and indirect protection.
- This vaccine strategy provides broad coverage against the most common Shigella serotypes causing diarrheal disease.
Background:
Shigella, a major diarrheal disease pathogen worldwide, is the target of vaccine development. The Global Enteric Multicenter Study (GEMS) investigated burden and etiology of moderate-to-severe diarrheal disease in children aged <60 months and matched controls without diarrhea during 3 years at 4 sites in Africa and 3 in Asia. Shigella was 1 of the 4 most common pathogens across sites and age strata. GEMS Shigella serotypes are reviewed to guide vaccine development.
Methods:
Subjects' stool specimens/rectal swabs were transported to site laboratories in transport media and plated onto xylose lysine desoxycholate and MacConkey agar. Suspect Shigella colonies were identified by biochemical tests and agglutination with antisera. Shigella isolates were shipped to the GEMS Reference Laboratory (Baltimore, MD) for confirmation and serotyping of S. flexneri; one-third of isolates were sent to the Centers for Disease Control and Prevention for quality control.
Results:
Shigella dysenteriae and S. boydii accounted for 5.0% and 5.4%, respectively, of 1130 Shigella case isolates; S. flexneri comprised 65.9% and S. sonnei 23.7%. Five serotypes/subserotypes comprised 89.4% of S. flexneri, including S. flexneri 2a, S. flexneri 6, S. flexneri 3a, S. flexneri 2b, and S. flexneri 1b.
Conclusions:
A broad-spectrum Shigella vaccine must protect against S. sonnei and 15 S. flexneri serotypes/subserotypes. A quadrivalent vaccine with O antigens from S. sonnei, S. flexneri 2a, S. flexneri 3a, and S. flexneri 6 can provide broad direct coverage against these most common serotypes and indirect coverage against all but 1 (rare) remaining subserotype through shared S. flexneri group antigens.
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