Intracutaneous and intravenous injection of pyrogenic, non-lethal doses of bacterial endotoxin were found to increase the infectivity of pathogenic but not non-pathogenic staphylococci in rabbit skin. The increased infectivity of the microorganism was characterized by accelerated multiplication at the site of inoculation and by the production of necrosis and hemorrhage locally. Histologically, the infection of skin in endotoxin-prepared animals was characterized by necrosis, masses of bacteria, but absence of leukocytic infiltration into the area of bacterial growth. The infectivity of staphylococci in skin of endotoxin-prepared rabbits could be controlled by antibody to the alpha hemolysin of the microorganism. The effect of endotoxin upon staphylococcal infection was demonstrable only within 4 hours after injection of the endotoxin. It could not be prevented with chlorpromazine or dibenamine and was closely related to the effect of endotoxin upon leukocytes. It was suggested that the effect of endotoxin upon leukocytes was probably responsible for its influence upon staphylococcal infection. The implications of these findings in the pathogenesis of staphylococcal infection are discussed.

Animals↗

PubMed1961

Studies on the pathogenesis of staphylococcal infection. II. The effect of non-specific inflammation.

Studies have been described in which the effect of early and late or established inflammation, upon staphylococcus infection of rabbit skin has been evaluated. Inflammation was produced in skin by thermal, chemical, bacterial and immunological injury, and it was found that the area of inflammation was more susceptible to staphylococcus infection than was normal skin if the bacteria were injected within 2 to 3 days after the injury. When staphylococci were injected into an area of inflammation of over 3 days' duration, there appeared to be an increase in local resistance to infection. The way in which inflammation was produced seemed to have a little influence upon the effects observed. This influence of non-specific inflammation upon staphylococcus infection was compared with the influence of specific bacterial hypersensitivity, which also is associated with an increase in infectivity of the microorganism in sensitized animals. It was concluded that specific bacterial hypersensitivity probably increases susceptibility to infection with the staphylococcus in the same way as non-specific inflammation. The general significance of non-specific inflammation upon infection is also discussed.

Animals↗

PubMed1961