The chemical structures of surface polysaccharides from Acinetobacter baumannii for glycoconjugate vaccines

Acinetobacter baumannii ( A. baumannii ) is a multidrug-resistant Gram-negative pathogen of global clinical concern. Its surface polysaccharides, including capsular polysaccharides (CPS) and lipopolysaccharides (LPS), are major virulence factors that enhance bacterial survival in hostile host environments. This review comprehensively summarizes the chemically diverse structures of these polysaccharides, particularly those containing non‐classical sugars such as pseudaminic acid (Pse), legionaminic acid (Leg), quinovosamine (Qui), and other rare monosaccharides. These CPS and LPS glycans are promising targets for novel therapeutics. The chemically synthesized glycoconjugate vaccines targeting these glycans elicit protective antibodies and confer effective immunity in animal models, highlighting their potential in combating A. baumannii infections. Therefore, understanding these polysaccharide structures provides valuable insights for developing novel therapeutic strategies, in particular glycoconjugate vaccines, against A. baumannii infections.