Tolerance and other biological properties of Vibrio parahaemolyticus endotoxins.

Biological properties of endotoxins prepared from three strains of Vibrio parahaemolyticus were compared with reference to commercially prepared Salmonella typhi endotoxin. Endotoxin assays performed in rabbits included dermal Shwartzman reactivity, pyrogenicity, heat stability, and ability to induce tolerance as well as cross-tolerance. Mice were used for endotoxin LD50 determinations. Results showed V. parahaemolyticus endotoxins were similar to that of S. typhi strain O901. Induction of tolerance to V. parahaemolyticus strain 11590 endotoxin resulted in complete cross-tolerance to S. typhi endotoxin, and vice versa. Partial cross-tolerance to S. typhi endotoxin was demonstrated with rabbits rendered tolerant to endotoxin from V. parahaemolyticus strains Sak-3 and FC1011. Absorption spectra, nitrogen, phosphorus and carbohydrate analyses revealed additional similarities between endotoxins from V. parahaemolyticus and endotoxin from a member of the Enterbacteriaceae.

[Polyamines in microorganisms sensitive and resistant to antibiotics]. / Poliaminy u mikroorganizmov, chuvstvitel'nykh i ustoichivykh k antibiotikam

Intracellular contents of polyamine dancyl derivatives were determined by the method of thin-layer chromatography in Coli and typhoid fever bacteria sensitive to antibiotics and their variants resistant to streptomycin, levomycetin, chlortetracyline and neomycin. Increased levels of spermidine and putrescin in the antibiotic resistant cultures were found. The increased levels of the polyamines correlated with changes in the content of nucleic acids. It is supposed that the increase in the content of the polyamines in the antibiotic resistant bacteria was the result of accumulation of nucleic acids by them.

Biochemical, immunochemical and immunobiological properties of a chloramphenicol-resistant Salmonella typhi strain isolated in Mexico.

The authors have compared the biochemical, immunochemical and immunobiological properties of a chloramphenicol-resistant S. typhi strain isolated during the typhoid fever epidemic in Mexico of 1972 and those of a chloramphenicol-sensitive strain (S. typhi Ty2). They have found no difference in the chemical composition of the two strains. The immunobiological investigations have shown, that the chloramphenicol-resistant strain contains less Vi antigen, it is less virulent on mice, and its active and passive mouse-protective ability is lower than that of the chloramphenicol-sensitive S. typhi Ty2 strain. These findings supported by the result of the electrophoretic analysis suggest that the chloramphenicol-resistant strain is a VW strain, while the chloramphenicol-sensitive strain is a full V strain; the quantitative difference found between the immunogenicity of the two strains to the advantage of the chloramphenicol-sensitive strain may probably be explained by this fact. On the basis of their immunological investigations the authors are of the opinion, that vaccines prepared from chloramphenicol-sensitive S. typhi strains (provided these are full V strains, as e.g. the S. typhi Ty2 strain) will protect most likely also man against infection due to chloramphenicol-resistant S. typhi strains.