Measurement of culturable airborne staphylococci downwind from a naturally ventilated broiler house

The objective of this study was to estimate the possible travel distance of airborne bacteria emitted from a naturally ventilated broiler house by using staphylococci as indicator organisms. Air samples were taken during the second half of three fattening periods with Impinger (AGI-30) in the barn and simultaneously upwind and downwind from the building. Staphylococci concentrations varied between 1 x 10(6) and 1 x 10(7) cfu m(-3) in the barn. No Staphylococci were detected in air samples at the upwind side. A strong exponential decrease of these bacteria was observed at three sampling heights (1.5, 4.0 and 9.5 m) in the main wind direction downwind of the barn. Staphylococci concentrations up to 5.9 x 10(3) cfu m(-3) were detected at the farthest sampling point (333 m) downwind. Identification to the species level by means of a 16S-23S ITS PCR confirmed that Staphylococcus spp. from downwind samples originated from the barn. Staphylococci served as an useful indicator to demonstrate the travel distance of bacterial emissions originating from a naturally ventilated broiler house. These findings indicate that airborne transmission of viable bacteria from this type of housing system to adjacent residential dwellings or animal houses several hundred metres away is possible.