The indoor pool water was kept at temperatures of 92 degrees to 94 degrees F and was treated with hydrogen peroxide rather than chlorine. The team found that pathogens thrived inside hydrogen peroxide bubbles produced at the pool surface and were dispersed as the bubbles became airborne and burst. The hydrogen peroxide also eliminated microbes competing with "Mycobacterium avium," they reported.
Health inspectors typically capture and culture microorganisms found in such environments to assess the number of pathogen species, an approach that misses many airborne bacteria that are difficult to grow in a lab environment. The new approach allowed researchers to survey more than 1,300 ribosomal RNA genes from different bacteria and fungi in the pool air and water and identify more than 600 unique sequences, including "Mycobacterium avium."
Hernandez led the sampling, and microbial analysis was done at CU-Boulder.
"This highlights the need to modernize public health methodology," said Pace, recipient of a $500,000 MacArthur "genius grant" in 2001 for his studies on the range and diversity of microbial life. "Public health progress has fallen in recent years, in part because of a shift in the nation's priorities toward bio-weapons research that diverts valuable money and resources away from very basic and important issues."
Higher winter levels of airborne pathogens in such enclosed pool areas are likely due to seasonal ventilation practices, including closed doors and windows during cold periods, said Pace. Since the study, the rate of air exchange in the pool area has been increased and additional air filters have been installed that have been shown to capture and remove up to
Source:University of Colorado at Boulder
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