ESTIMATION OF AIRBORNE FUNGAL FLORA BY ANDERSEN SAMPLER VERSUS GRAVITY SETTLING CULTURE PLATE .I. ISOLATION FREQUENCY AND NUMBERS OF COLONIES

The gravity settling culture (GSC) plate and the sequential impaction cascade sieve volumetric air (SICSVA) sampler devised by Andersen were critically compared in the estimation of airborne fungal flora. One hundred twenty-seven side-by-side simultaneous 15 minute samples were obtained on Mehrlich's medium in Northern California. The SICSVA sampler collected 25 fungal types totaling 14,300 colonies, and the adjacent GSC plates displayed 18 genera in 1,091 colonies. Statistically significant differences in total colonies and frequency of isolation were noted for Penicillium, Alternaria, Aspergillus, Gliocladium, Pullularia, Rhizopus, Saccharomyces, Stemphilium, Ustilago zeae, and other (unidentified) fungi. The capability of the SICSVA sampler to isolate volumetrically in a reproducible fashion numbers of airborne fungal spores was demonstrated. It is suggested that these colonies can be logically grouped into a fraction that generally would lodge in the upper respiratory tract and another fraction which, because of the small spore sizes, would largely be capable of lung penetrance. Both methods demonstrated a capacity to produce falsely negative data, but this was especially true for the GSC plate. The GSC plate method cannot be endorsed for the quantitative evaluation of airborne fungal spores. © 1969.