Bactericidal capacity of plasma and granulocytes against Escherichia coli in the small-for-dates newborn

Infections due to Gram-negative bacteria in newborns and especially small-for-dates newborns sometimes run a dramatic course and have a high mortality rate. The bactericidal effect of plasma and granulocytes was determined by the method of Balch et al [1] in 27 small-for-dates term newborns and 19 normal term newborns. The number of killed bacteria was practically the same in th mixture of granulocytes and plasma in both groups. On the other hand, a threefold decrease of the bactericidal effect of plasma was observed when it was applied alone, without granulocytes. This may indicate that the defect is more in the plasma than in the granulocytes, and is probably due to the failure of class IgM antibodies to cross the placental barrier.