ABSTRACT
Surface epitopes of Gram-negative microorganisms. They are either proteins (fimbriae) or acid polysaccharides found on the surface of
Klebsiella
and
Escherichia coli
microorganisms. K antigens are exterior to somatic O antigens. They are labile to heat and cross-react with the capsules of other microorganisms such as
Hemophilus influenzae
,
Streptococcus pneumoniae
,
and
Neisseria meningitidis.
