Sampling Performance for Bioaerosols by Flow Cytometry with Fluorochrome

Although culture-based analysis remains the primary method for environmental bioaerosol analysis, for better understanding and quantifying of bioaerosols both culture- and nonculture-based methods should be used and compared. Here, flow cytometry with fluorochrome (FCM/FL) was applied to evaluate the sampling performance of impingement (AGI-30 all-glass impinger) and filtration (track-etched polycarbonate filter) with different types of fluorescent dye staining (cell membrane integrity and metabolism) and then compared with a traditional culture method (culturability). Two bacterial aerosols (Escherichia coli and endospores of Bacillus subtilis) and two fungal aerosols (Candida famata and Penicillium citrinum spores) were studied. The bioaerosol viability during the sampling processes was highly influenced by bioaerosol characteristics (hardy or fragile), as well as by the fluorescent dyes with different physiological mechanisms. For better viability of the sampled bioaerosol, the impinger was superior to the filter. Moreover, it was found that sampling stress from filtration had more influence on the bioaerosol metabolism mechanism than cell membrane integrity. Furthermore, the differences between cell membrane integrity and the metabolism by sampling stress were found to be related to the bioaerosol species.

Acknowledgments

This work was partially supported by grant NSC 92-2320-B-002-149 from the National Science Council, Republic of China. Pei-Shih Chen was supported by a graduate scholarship from the same grant during the part of this research effort.

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