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Results for “MICROCOCCAL INFECTIONS/experimental”

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At least 19 recordsLinked to original sources
PubMed1957

Studies on bacteriemia. II. Further observations on the granulocytopenia induced by the intravenous injection of Staphylococci.

Intravenous injection of staphylococci produced a marked, transient granulocytopenia inrabbits. Leukopenia was rapidly followed by return of polymorphonuclear leukocytes to the peripheral blood, and normal circulating granulocyte levels were reestablished within 20 to 40 minutes. Differential arterio-venous leukocyte studies showed that polymorphonuclear leukocytes were trapped within the pulmonary vascular bed and, less constantly, in the splanchnic viscera during the initial 10 to 20 minutes following the injection of staphylococci. Granulocytes were subsequently found in larger numbers in blood leaving the lungs and splanchnic tissues, suggesting that entrapped polymorphonuclear leukocytes rapidly reentered the blood stream. This sequence of changes in circulating granulocytes was not significantly altered by splenectomy or the administration of cortisone. It has previously been shown that virtually all staphylococci in the blood stream are found within circulating polymorphonuclear leukocytes 10 to 40 minutes after the injection of culture (9). It is during this period that granulocytes return to the blood stream in large numbers. These observations suggest that staphylococci are phagocyted by polymorphonuclear leucocytes temporarily sequestered in the lungs and splanchnic viscera. It appears probable that some sequestered granulocytes containing living staphylococci subsequently return to the circulation. Such intraleukocytic staphylococci are believed to play a role in the maintenance of bacteriemia.

Agranulocytosis↗
PubMed1959

A quantitative study of the kinetics of blood clearance of P32-labelled Escherichia coli and Staphylococci by the reticuloendothelial system.

1. The clearance of P(32)-labelled heat-killed E. coli and staphylococci from the blood follows an exponential function of the time, and the bacteria are phagocytized principally by the RES of the liver and spleen. 2. The rates of clearance of equivalent number of E. coli from the blood is rapid in rabbits and slow in mice and appears to be related to the level of antibodies in the serum of these animals. 3. Unlike E. coli, staphylococci are cleared rapidly and efficiently by the RES from the blood of mice which have a sufficient level of serum antibody against these bacteria. 4. The numbers of bacteria, phagocytized by the liver or the spleen respectively, depend upon the rate of clearance and the extent of opsonization of the bacteria. Rapidly cleared, well opsonized E. coli are removed almost exclusively by the liver, while less efficiently phagocytized bacteria are also cleared by the spleen in large numbers. 5. The rate of clearance of E. coli and the efficiency with which they are phagocyted by the RES in mice have been shown to be directly related to the level of antibody in the serum. 6. Treatment of mice with S. typhi or Serratia marcescens endotoxins increases the rate of clearance of E. coli from the blood and the level of antibody against E. coli in the serum. The enhanced clearance of E. coli can be transferred to normal mice by the serum of endotoxin-treated mice.

Animals↗
PubMed1954

Experimental Staphylococcus infection in the hamster cheek pouch: the process of localization.

Small amounts of staphylococcus suspensions were injected into the cheek pouches of hamsters. Within 5 hours, the organisms were recovered from all outlying areas of the pouches, and in the following hours the entire structures showed vasodilation, edema, petechiae, and accumulation of leukocytes in the venules. Leukocytosis also occurred at this time. Between 24 and 48 hours, well defined abscesses developed at the sites of injection, and there was a sharp decrease in the bacteria in all other areas. From the 3rd day onward, organisms were only occasionally recovered from tissue outside the abscesses. At this period of localization, the generalized edema and petechiae also subsided, as did the leukocytosis. Localization of infection was not due to a walling off process, since the bacteria were disseminated through the entire pouches in the 1st few hours, but these organisms diminished rapidly, while those at the original injection sites continued to grow and reproduce for several days. Localization of infection appeared to be due to the inability of the bacteria carried away from the site of injection to reproduce. This in turn may have been due to dilution, to lack of sufficient toxin to produce a necrotic substrate, or to greater accessibility of these organisms to phagocytes.

Animals↗