Legionella disinfection changes the microbial ecology or microbiome in a hospital hot water system, says a study published in PLOS ONE Journal.

“As secondary disinfection is becoming more widely used to control Legionella, we need to understand how these chemicals change the bacterial flora in the water and what these changes imply,” says Janet E. Stout, PhD, director of Special Pathogens Laboratory.

Dr. Stout, principal investigator of the study, and researcher Julianne Baron, PhD, from the University of Pittsburgh Graduate School of Public Health used next generation molecular sequencing methods—high throughput Illumina 16S rRNA region sequencing and 454 sequencing, to evaluate samples from a hospital’s hot water system treated with onsite monochloramine.

The results in, Shift in the Microbial Ecology of a Hospital Hot Water System Following the Introduction of an On-Site Monochloramine Disinfection System, show an immediate shift in the microbial population or microbiome. These techniques along with traditional culture, showed changes in Legionella, including rebound during a period of ineffective treatment.

“The microbiome of the built environment is a new frontier of science. As science and medicine are exploring how bacteria can impact health, it only makes sense to look at the changes in our drinking water,” says Stout. “More studies are needed to understand the consequences of Legionella disinfection technologies in water systems.”