The influence of the O and K antigens of Klebsiella aerogenes on surface hydrophobicity and susceptibility to phagocytosis and antimicrobial agents.

The surface hydrophobicity of Klebsiella aerogenes is influenced by the presence of capsular (K) and lipopolysaccharide (O) antigens. Loss of both K and O antigens (K-O-), but not the K antigen alone (K-O+), increased surface hydrophobicity and susceptibility to phagocytosis. Unheated serum (i.e., containing complement) increased the surface hydrophobicity and phagocytosis of the K-O+ and K-O- strains, but not of the K+O+ encapsulated parent strain. Despite the altered susceptibility to phagocytosis caused by the presence or absence of the K and O antigens, their loss did not influence sensitivity to a range of hydrophilic, hydrophobic or cationic antimicrobial agents.