EXPOSURE TO BACTERIA IN SWINE-HOUSE DUST AND ACUTE INFLAMMATORY REACTIONS IN HUMANS

Inhalation of swine-house dust may cause an acute airway inflammatory condition (organic dust toxic syndrome). Thirty-eight healthy subjects were exposed to swine dust while weighing swine for 3 h. We studied t he correlation between acute health effects and the inhaled bacterial exposure markers peptidoglycan (the main constituent of the cell walls of gram-positive bacteria, but also present in lesser amounts in gram -negative bacteria) and lipopolysaccharides (LPS; present only in gram -negative bacteria). LPS activity in airborne dust was measured with t he Limulus amebocyte lysate assay (LPSLAL), and the total LPS was esti mated from 3-hydroxy fatty acids, which were measured with gas chromat ography-mass spectrometry (GC-MS) (LPSGC-MS). Peptidoglycan was estima ted from muramic acid measured with GC-MS. The median (25th to 75th pe rcentile) concentration of inhalable dust was 21 (16 to 25) mg/m(3). L PSLAL was 1.2 (0.9 to 1.4) mu g/m(3); LPSGC-MS was 3.9 (2.5 to 4.9) mu g/m(3); and the peptidoglycan concentration in airborne dust was 6.5 (2.7 to 13) mu g/m(3) All exposure markers correlated significantly wi th an increase in serum interleukin-6. LPSLAL showed the highest corre lation (r(2) = 0.29) and total inhaled dust the lowest (r(2) = 0.09). LPSLAL also correlated with symptoms and with an increase in bronchial responsiveness and decrease in vital capacity (VC). Peptidoglycan, bu t not LPSLAL, correlated with an increase in the blood granulocyte con centration and in body temperature. The results suggest that several m icrobial agents in inhaled swine-house dust may contribute to acute sy stemic health effects.