The effect of administration of immunoglobulin to newborn rats with Escherichia coli sepsis and meningitis.

Newborn rats 24-36 h old were injected transthoracically with various doses of Escherichia coli K1. Eighty-six of 92 rats which received 10(4) colony-forming units/g body weight were dead within 48 h. Two h after injection, E. coli were recovered from the blood of six of six rats and from the cerebrospinal fluid of two of six. Sixteen h after injection, E. coli were recovered from all blood (7/7) and spinal fluid (11/11) specimens cultured. Animals inoculated with 10(4) E. coli/g exhibited neutropenia and depletion of the neutrophil storage pool. In other studies, newborn rats inoculated with E. coli were injected intraperitoneally with various doses of human serum immunoglobulin, modified for intravenous use (MISG). One hundred percent (25/25) injected with 1500 mg/kg lived. In contrast to infected animals injected with albumin (controls), MISG recipients did not develop neutropenia nor did they deplete their neutrophil reserves. The effects of treating infected animals with MISG, antibiotics, or a combination of antibiotics plus MISG were compared. When administered within 2 h after the E. coli, all treatments resulted in survival rates of over 75%. However, when delayed for 6 h, 63% (17/27) of antibiotic recipients, 50% (12/24) of MISG recipients, and 91% (30/33) of those receiving both treatments lived (p less than 0.01 versus antibiotics or MISG).