Airborne microorganisms and endotoxin in animal houses

Abstract

Abstract Concentrations of microorganisms, dust and bacterial endotoxin were determined in the air of 18 animal houses (four cowsheds, nine horse stables and five piggeries) in eastern Poland. Total mesophilic bacteria numbered 568.7–1480.7 colony forming units (CFU)x103 m-3 in piggeries, 43.9–280.5 CFU×103 m-3 in cowsheds, and 26.2–150.1 CFU×103 m-3 in horse stables. Corynebacteria (Corynebacterium spp., Arthrobacter spp.) predominated. Concentrations of Gram-negative bacteria, thermophilic actinomycetes and fungi were smaller (mostly in the range of 102-104 CFU m-3) except for one cowshed and two stables where concentrations of thermophilic actinomycetes exceeded 100 CFU×103 m-3. Thermoactinomyces vulgaris and Saccharopolyspora rectivirgula, both known to be strongly allergenic, were the predominant actinomycetes. Concentrations of airborne dust were 0.15–14.05 mg m-3. There were large concentrations of bacterial endotoxin in the air of piggeries, in the range 1.88–75.0 μg m-3, but concentrations were much smaller in other houses and mostly did not exceed a safe level of 0.1 μg m-3. The results show that the farm workers and housed animals can be exposed to large quantities of airborne microbes and their products that pose a potential risk of respiratory disease resulting from the immunomodulatory action of these organisms.