Measurement of dust-borne MRSA in pig farms using different approaches

Abstract Aims To obtain knowledge about 1) how to sample airborne MRSA and dust in the pig farm environment including effects of sampler on a) measured exposure, b) MRSA survival, and c) spatial and temporal variation in exposure, and 2) the association between exposure to MRSA, dust, and optical density. Methods and Results Airborne dust was sampled on five pig farms using five active and one passive samplers. Staphylococcus aureus and MRSA (as a subset of S. aureus) were quantified using selective agar media and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The Andersen sampler, electrostatic dust collectors (EDC), and GSP and IOM samplers with polycarbonate or Teflon filters were applicable for sampling airborne MRSA. The half-life of MRSA was not reduced by active sampling. A significant correlation was found between dust and S. aureus exposure within, but not between, farm section and farms. A significant spatial and temporal variation in dust and MRSA exposure was found within a stable. The dust sampling rate and the concentration of MRSA in the sampled dust decreased after five days of sampling. Conclusion Sampling using the GSP can be performed for 1 h without affecting the following half-life of MRSA. Sampling for MRSA using the EDC should not exceed three days due to overloading and the die-off of MRSA. Measurement of OD may be used as a proxy measure for dust exposure. To obtain knowledge about potential exposure, samples should be taken repeatedly and in different areas within a stable section. Significance and Impact of the Study Sampling method, sampling time, and number of samples taken, but not force of airflow on the filter, influence the measured potential exposure to MRSA and dust. This article is protected by copyright. All rights reserved.