1410 TREATMENT OF EXPERIMENTAL NEONATAL E. COLI Kl SEPSIS AND MENINGITIS WITH INTRAVENOUS IMMUNE GLOBULIN

Abstract

E. coli is a leading cause of infection in neonates and in many cases antibiotics alone are ineffective. Therefore, we tested the effect of intravenous immune globulin(IVIG) on neutrophil(neut) kinetics and survival. When 104 E.coli Kl/gm body wt was given transthoracically(TT) to 37 newborn rats, all died. Five of 6 blood cultures were positive(+) after 30 min; all were + in 2h. Spinal fluid was + in 1/6 by 30 min, in 2/6 by 2h, and in 7/7 by 6h. When 2.5 cc/kg of intraperitoneal IVIG was given simultaneously with TT E.coli, 8/18(44%) lived, with 5 cc/kg 14/17(82%) lived, with 20 cc/kg 17/18(94%) lived, and with ≥-30cc/kg 34/34 (100%) survived. IVIG recipients(30 cc/kg) released neut from their reserves more rapidly than did controls (after 2h neut reserve=4.9±0.7×106 vs 8.1±0.8×106 in controls, x±SEM, p<0.01). IVIG recipients did not become neutropenic (2.7±0.4×103 neut/mn3 vs 0.2±0.1 ×103/mm3 22h after inoculation, p<0.001), nor did they completely exhaust their marrow neut reserve (3.3±0.5×106 vs 1.4±0.3×106 after 22h, p<0.005). When IVIG was delayed for 12h after TT E.coli, 3/17(18%) lived but when ampicillin (200 mg/kg/day) and gentamicin (5 mg/kg/day) were given at 12h instead of IVIG 11/17(65%) lived. When both IVIG and antibiotics were given, 12/14(86%) survived. When treatment was delayed for 16h, 5/17 (29%) antibiotic vs 1/17(6%) IVIG recipients lived, but 13/22 (59%) which received both survived. Thus, IVIG facilitated marrow neut release, prevented neutropenia and marrow neut exhaustion, diminished mortality, and enhanced the effect of antibiotics.