Symptoms of pulmonary disease caused by M. avium can include tiredness, a persistent, dry cough, shortness of breath, weakness and "generally feeling bad," said Pace. Immune-compromised people like pregnant women, the elderly and those who are fighting off other diseases are more prone to experience such symptoms, said Pace, a professor in the molecular, cellular and developmental biology department.
The CU-Boulder researchers sampled showerheads in homes, apartment buildings and public places in New York, Illinois, Colorado, Tennessee and North Dakota.
Although scientists have tried cell culturing to test for showerhead pathogens, the technique is unable to detect 99.9 percent of bacteria species present in any given environment, said Pace. A molecular genetics technique developed by Pace in the 1990s allowed researchers to swab samples directly from the showerheads, isolate DNA, amplify it using the polymerase chain reaction, or PCR, and determine the sequences of genes present in order to pinpoint particular pathogen types.
"There have been some precedents for concern regarding pathogens and showerheads," said Pace. "But until this study we did not know just how much concern."
During the early stages of the study, the CU team tested showerheads from smaller towns and cities, many of which were using well water rather than municipal water. "We were starting to conclude that pathogen levels we detected in the showerheads were pretty boring," said Feazel, first author on the study. "Then we worked up the New York data and saw a lot of M. avium. It completely reinvigorated the study."
In addition to the showerhead swabbing technique, Feazel took several individual showerh
|Contact: Norman Pace|
University of Colorado at Boulder