THE MULTIPLICATION AND VIRULENCE OF SEPTICEMIC PATHOGENS WHEN CULTIVATED IN DEFIBRINATED BLOOD
FORT DETRICK FREDERICK MD
Pagination or Media Count:
The multiplication and change in virulence were traced in Erysipelothrix rhusiopathiae, Listeria monocytogenes, Pasteurella avicida, Pasteurella pseudotuberculosis, Bacterium pyocyaneum and Salmonella typhimurium when these were cultured in defibrinated sheep and swine blood taken under sterile conditions. The increase in virulence, determined by the difference between initial virulence and virulence after culturing in blood in vitro for 24 hours at 37C, was specific for each of the six investigated species of bacteria. For Past. avicida virulence increases many billion fold for Past. pseudotuberculosis about 2000 fold for Bact. pyocyaneum -- in blood -- 60 fold and in sheep blood 30 fold for Salm. typhimurium 600 fold for Ery. rhusiopathiae 60 fold and for List. monocytogenes about 300 fold. These results provide a basis for undertaking investigations in order to trace the extent to which the numbers and virulence of septicemic pathogens increase in blood -- even in the infinitesimal quantities of blood taken by bloodsucking arthropods in transmissive bacterial infections. This would clarify experimentally the actual part played by, and the significance of, Arthropoda in the epizootiology, epidemiology and natural foci of a considerable number of infectious diseases.