Comparison of the efficiency of sampling devices for aerosolized Burkholderia pseudomallei

Previous studies have demonstrated that aerosol sampling devices can have deleterious effects on bacteria due to stresses intrinsic to the sampling processes. Although a significant amount of work has been carried out to develop animal models of inhalational melioidosis, little information has been reported on the effects of the aerosol sampling devices on the causative bacterium, Burkholderia pseudomallei. The aim of this study was to compare the efficiencies for collection of aerosolized bacteria in three sampling devices that have been used in studies utilizing aerosolized B. pseudomallei. The data from this study demonstrate the equivalence of the Mercer impactor, gelatin filter, and model 7541 AGI for sampling respirable aerosols containing B. pseudomallei across a range of aerosol concentrations. It was also determined that the retention efficiency of gelatin filters for culturable B. pseudomallei was near unity, suggesting that desiccation of collected material did not occur for the short sampling period tested. The retention efficiency of the model 7541 AGI for culturable B. pseudomallei was significantly less than unity, and it was determined that this decrease was likely due to the stresses associated with repetitive sampler bubbling. The results of this study also confirmed the results of previous studies on the deleterious effects of the Collison nebulizer on microorganisms and extended these data to include B. pseudomallei.