Measurement of airborne and surface-associated microorganisms using conventional analysis and quantitative PCR

Human exposure to airborne microorganisms can result in a variety of adverse health effects, including infectious diseases and allergic or irritant responses. Methods for the detection of microorganisms on surfaces are needed to locate biocontamination sources and to relate surface and airborne concentrations. The objectives of this research were: (1) to relate bioaerosol concentrations dispersed from source materials to the biocontamination concentration of the source, and (2) to develop enhanced analysis methods for measuring surface-associated microorganisms using quantitative polymerase chain reaction (QPCR). Air handling system duct materials and flooring materials were contaminated with a test microorganism in an experimental room. Protocols using a variety of surface sampling methods were developed for measuring target microorganism concentrations on the materials. The airborne dispersal of microorganisms from the contaminated materials was measured in the experimental room. In addition, an enhanced detection method was developed for the assessment of a target biocontaminant on surfaces using QPCR analysis.; For air handling system material studies, duct sections were contaminated with a known concentration of the fungus, Penicillium chrysogenum , and inserted into the air handling system of an experimental room. The air handling system was then operated and bioaerosol concentrations were measured in the room. Results showed that spores were dispersed from fungal colonies on air handling system duct materials during normal operation of the system. There was no significant difference in spore dispersal from the three types of contaminated duct materials.; Flooring materials were contaminated with known concentrations of P. chrysogenum spores and bioaerosol concentrations were measured in the room before and after walking. Results indicated that the type of flooring material and the biocontamination level affect the magnitude of airborne dispersal of fungal spores after walking activity.; Surface sampling methods and QPCR were evaluated to develop a protocol for the enhanced detection of a target bacterial biocontaminant on flooring materials. QPCR and culture analyses were used to quantitate the presence of Bacillus subtilis endospores on flooring materials with four surface sampling methods. The data showed greater overall sensitivity with QPCR than culture analysis. These results demonstrate the capabilities of QPCR to enhance detection and enumeration of biocontaminants on surface materials.