A Comparison of Two Surface Sample Collection Devices for Use in Polymerase Chain Reaction Based Detection of Pneumocystis carinii in House Dust

Abstract

A polymerase chain reaction assay was optimized to detect P. carinii cysts in composite dust samples. The optimal assay was capable of detecting as few as 10(3) P. carinii cysts in 50 mg of dust. Two dust collection devices were evaluated for efficiency and precision of collection of bulk dust and compatibility with the optimized PCR protocol for P. carinii DNA detection. A handheld vacuum cleaner equipped with a high-retention bag was found to be superior to a 37-mm filter cassette attached to an electrically powered vacuum pump in terms of dust collection efficiency (87% [n = 37] versus 81% [n = 35]), although the precision of the two devices as assessed by the standard deviation was similar (6.2% versus 6.3%). However, the vacuum cleaner method was not as compatible with the PCR-based detection assay as the filter cassette method. The filter cassette appears to be a better device for use in conjunction with PCR-based detection of P. carinii DNA in bulk dust samples from both smooth and carpeted surfaces.

Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels

“…Most fungal spores are efficiently collected by the most commonly used particle samplers (Burge, 2002). Surface sampling, when used in conjunction with molecular techniques, can help to narrow down the list of potential sources (Maher et al., 2002). We applied swabbing of doorframes as a new method to collect dust samples for fungal DNA analysis in indoor environments.…”