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Query: UMLS:C0341503 (bacterial peritonitis)
 1,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An animal model for study of bacterial elimination from the peritoneal cavity is presented. Using Escherichia coli and Bacteroides fragilis as infecting agents, two elimination patterns emerged. The patterns were related to the surface properties of the micro-organisms. The concentration of both species was greatly reduced within 2 to 4 hours after peritoneal contamination with 10(10) CFU. The elimination of B. fragilis was contemporaneous with mobilization of granulocytes into the peritoneal cavity, and was probably attributable to bactericidal action of the granulocytes. Most of the E. coli inoculum, however, was cleared before the granulocyte mobilization. Cell-free peritoneal fluid was found to have a bactericidal effect against a rough strain of E. coli, but not against a smooth strain, as demonstrated in vitro. This effect was inhibited by pretreatment of the peritoneal fluid with EDTA, EGTA or heat, which suggested that the alternate pathway of the complement system was involved. In vivo the rough strain of E. coli was rapidly eliminated, while elimination of the smooth strain followed the B. fragilis pattern. It is concluded that bacterial surface properties are important in bacterial peritonitis.
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PMID:Elimination patterns of Escherichia coli and bacteroides fragilis from the peritoneal cavity. Studies with experimental peritonitis in pigs. 635 20

Hemoglobin (Hb) is a toxic molecule responsible for the extreme lethality associated with experimental Escherichia coli peritonitis, but the mechanism has yet to be elucidated. Hb, but not globin, showed toxic effects in a live E. coli model but not in a model using killed E. coli. Methemoglobin, hematin, and the well-known Fenton reagents iron and iron-EDTA demonstrated the same lethal effect in E. coli peritonitis as Hb, while the addition of the Fenton inhibitors desferrioxamine (DF) and diethylenetriamine pentaacetate removed most of the cytotoxic activity of iron. Administration of a combined dose of superoxide dismutase and catalase minimized the action of Hb and iron-EDTA, suggesting that both O(2)(.-) and H(2)O(2) are involved in the toxic action of Hb in this rat model. The combination of the antioxidative enzymes and DF further suppressed iron-mediated lethality. An electron spin resonance technique with the spin-trapping reagent 5, 5-dimethyl-1-pyroline-N-oxide (DMPO) showed O(2)(.-) generation in the peritoneal fluid of rats injected with E. coli alone or E. coli plus iron-DF, and (.)OH generation was detected in the peritoneal fluid of the rats injected with iron-EDTA. Hb did not show any spin adduct of oxygen radicals, suggesting that Hb produces non-spin-trapping radical ferryl ion, which decayed the spin adduct of DMPO. In the presence of Hb or iron-EDTA, O(2)(-)-generating activity and viability of phagocytes decreased, whereas lipid peroxidation of peritoneal phagocytes increased. Generation of oxygen radicals and lipid peroxidation did not differ in the live and dead bacterial models. Bacterial numbers in the peritoneal cavity and blood were markedly increased in the live bacterial model with Hb and iron-EDTA. The Fenton inhibitor iron-DF prevented the loss of phagocyte function, lipid peroxidation, and bacterial proliferation. These results led us to conclude that the lethal toxicity of Hb in bacterial peritonitis is associated with a Fenton-type reaction, the products of which decrease phagocyte viability, through the induction of lipid peroxidation, allowing bacterial proliferation and resulting in mortality.
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PMID:Hemoglobin toxicity in experimental bacterial peritonitis is due to production of reactive oxygen species. 1054 90