Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization.

Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.