D- and L-Lactic Acid in Chronic Sinusitis as a Marker of Leukocyte and Bacterial Metabolism

Abstract

The anaerobic environment in purulent sinusitis is reflected by the accumulation of lactic acid in the secretion. L-Lactic acid originates mainly from leukocytes and the D-form is exclusively produced by growing bacteria. In this study the latter was used as a marker of bacterial metabolism. Secretion was aspirated from 24 patients with either purulent or nonpurulent chronic sinusitis and frozen in liquid nitrogen. Samples were assayed for both isomers of lactic acid by an enzymatic method. In chronic purulent and nonpurulent sinusitis L-lactic acid concentration was 16.3 and 1.1 mmol/kg w/w, respectively. D-Lactic acid was only detected in two purulent and three nonpurulent secretions and in small concentrations (0.7 and 0.3 mmol/kg w.w., respectively). This indicates that the increased lactate concentration in purulent sinusitis is of leukocytic origin and that the bacteria in chronic sinusitis are metabolically inactive, and thus in a stationary growth phase.