Klebsiella pneumoniae Capsular Polysaccharide (Serotype K1) (K1 CPS)

The capsular polysaccharide (CPS) of *Klebsiella pneumoniae* serotype K1 is a high-molecular-weight, extracellular carbohydrate structure that forms the outermost layer of the bacterium. It is a major virulence factor, providing protection against host immune responses and contributing to the pathogen’s ability to cause severe infections, including pyogenic liver abscesses and invasive diseases. The K1 CPS consists of repeating trisaccharide units with unique features including extensive pyruvation of glucuronic acid, acetylation of fucose, and the presence of a fucose subunit. It functions primarily by blocking recognition by host immune receptors on phagocytes, enabling the bacteria to evade phagocytosis and clearance. Serotype K1 is among the most virulent types. Therapies targeting CPS are under investigation.

Other names

K. pneumoniae K1 capsular polysaccharideK1 serotype capsuleKlebsiella K1 CPS

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