Antibacterial effect of Surfacen and surfactant protein A (SP-A) against a clinical isolate of Streptococcus pneumoniae

摘要

Surfacen®, a clinical preparation of exogenous pulmonary surfactant, and pulmonary surfactant protein A (SP-A) were evaluated in relation to their in vitro effect on the growth of a clinical isolate of Streptococcus pneumoniae. The bacterium was incubated in a normal saline solution for 5 h at 37oC, together with Surfacen® and SP-A. Surfacen® showed antibacterial activity against the clinical isolate of Streptococcus pneumonia at 10 or 25 mg/ml with one logarithm of reduction of the bacterial growth; also SP-A had the same effect at concentrations of 0.25, 0.5 or 1 mg/ml. Porcine SP-A addition at the highest Surfacen® concentration (25 mg/ml) showed a higher antibacterial activity by reducing two logarithms of bacterial growth.