Assessment of the Bacterial Contamination and Remediation Efficacy After Flooding Using Fluorometric Detection

Abstract

Abstract In the aftermath of flooding, rapid response assessment and cleanup is critical to recovery. In this study, the level of contamination of bacteria on surfaces in flooded houses was estimated and compared to the level found on surfaces in non-flooded houses with a rapid field test based on hydrolase enzyme activity present in bacteria and by measuring endotoxin. Sampling was performed by swabbing a 9 cm2 area using sterile cotton swabs wetted with a bacteriostatic buffer. A correlation between endotoxin levels and levels of hydrolase activity was seen (R2 = 0.6469, P < 0.0001). The median value and the variance ofthe result distribution were higher in flooded buildings as compared to non-flooded buildings. In the non-flooded buildings, surfaces were divided into visually clean and visually dirty. As expected the level of bacteria was higher on the visually dirty surfaces, and overall the hydrolase activity correlated well with the visual inspection. Using the results from the visually clean surfaces in the reference buildings as the criteria for clean, four methods of cleaning were tested for their ability to reach these criteria.