Microbial Activity and Airborne Culturable Microbial Concentrations in South Georgia Homes

Indoor microorganisms and microbial allergens can lead to harmful respiratory effects in the human body such as allergies, asthma, chronic bronchitis, infections, and even contamination of food stuffs. This study was conducted in order to test the indoor microbial pollutants in local Statesboro homes, and relate the findings to respiratory disease symptoms of occupants. Thus far, samples have been collected and data analyzed for 15 homes. This specific part of the study focuses on the amount of adenosine triphosphate (ATP) in homes. ATP is a source of energy produced through glucose metabolism and the citric acid cycle. ATP levels can be an indirect estimation of overall microbial activity and may indicate microbial cell viability and the metabolic status. Therefore, we have measured levels of total ATP in swabbed settled dust in homes and also conducted sampling of airborne culturable molds and bacteria in parallel. ATP levels were determined in swabbed dust samples collected from 10 cm2 floor surfaces using a kit, which utilized luciferin-luciferase fluorescence reaction and a luminometer, which then quantified ATP levels as relative light units (RLU). For air sampling, a Biostage viable impactor was utilized, which comprises an inlet cone, a 400-hole impactor stage, and a base that holds a standard-size agar plate. A pump connected to this impactor pulls microorganisms in air at 28.3 L/min flow rate on the agar surface for approx. five minutes. After sampling, agar plates were incubated at 30å±2å¡C for 24 to 72 h. Colony counts were converted to airborne concentrations (CFU/m3) after positive hole corrections. Levels of ATP, airborne culturable mold and bacteria in homes (n = 15) were 894.35 å± 1307.76 RLU/sample, 228 å± 243 CFU/m3, and 468 å± 283 CFU/m3, respectively. Preliminary data indicate high levels of microbial activity and culturable airborne microorganisms in the investigated South Georgia homes.