A disposable sampler for collecting volumetric air samples onto agar media

Abstract

Rationale Measurement of exposure to fungi continues to be of interest as an aid in the diagnosis of respiratory allergies. Settle or gravity plates, which are commonly used, provide little information about actual concentrations of fungal spores in the air. The well-known Andersen sampler is too expensive to send home with patients. We have developed and tested the Biocassette, a disposable version of the Andersen sampler. Methods We have conducted 50 paired tests comparing the Biocassette with the Andersen. We compared total recoveries and recoveries of Penicillium graphically and statistically following transformation to approximate normality. Total recoveries were log-normally distributed, and transformed data from the two samplers was linearly related (y=0.6433x+2.083, R2=0.4748). Results Paired T-tests on the log-transformed data failed to reject the null hypotheses (no difference between the two samplers). Penicillium data were subjected to a square root transformation to approximate normality. These transformed data were linearly related (y=0.7788x+2.2018, R2=0.5495, and no significant differences were revealed in the Paired T-Test. Conclusions The Biocassette appears to produce results that are comparable to the Andersen sample both for total culturable fungi and for small spores as represented by Penicillium. The sampler should be a valuable addition to the allergist's environmental control arsenal.