Characteristics of lipopolysaccharides ofSalmonella typhi isolated from carriers and patients suffering from typhoid fever

Lipopolysaccharides (LPS) ofSalmonella typhi strains, isolated from carriers and patients suffering from typhoid fever, were characterised according to their biochemical properties, morphological structure and degree of aggregation of complexes. All preparations of LPS, regardless of their origin, were morphologically heterogeneous. Free electrophoresis and immunoelectrophoresis demonstrated that LPS preparations were composed of components possessing different mobilities in electric fields. LPS of bacterial strains isolated from both carriers and patients, split upon reaction in immunoelectrophoresis with specific antiserum 73, rabbit antiserum toSalmonella typhi Vi Bhatnagar and 0–901 split into anodic and cathodio fractions. The anodic fraction reacted similarly as Vi antigen. LPS fromSalmonella typhi Ty-2 yielded only the cathodic fraction, typical for O antigen. LPS from strains whioh were passaged twice in nutritional medium possessed identical properties as LPS from fresh cultures ofSalmonella typhi. Electron microscopy revealed that LPS appears as long bands, rods, ellipsoid forms and amorphous material. Contrary to amorphous material, the bands, rods and ellipsoid forms possessed three-layer structure.