Effect of prolonged bacteremia on leukocyte bactericidal function.

Neutrophil bactericidal function (NBF) was studied in dogs during intravenous infusions of Pseudomonas aeruginosa. Administration of 10(6) bacteria per minute over 3 hours was associated with a bacteremia level of about 10(3) organisms per milliliter of blood without adverse effects on NBF. Infusion of 10(7) organisms per minute resulted in blood bacterial counts in the upper 10(4) range and significantly impaired NBF. To determine the relative contribution of the spleen in bacterial phagocytosis, splenectomies were performed in additional dogs immediately prior to 5 hour infusions of 10(6) Pseudomonas aeruginosa per minute. Results revealed that splenectomy did not influence the blood bacterial clearance. These experimental findings emphasize the dominant role of polymorphonuclear leukocytes in bacterial defense.