Pseudomonas aeruginosa in CF and non-CF homes is found predominantly in drains

BackgroundFor patients with cystic fibrosis (CF) Pseudomonas aeruginosa infection is a major contributor to progressive lung disease. While colonizing strains are thought to be primarily environmental, which environments are important in lung colonization is unclear.MethodsWe took 11,674 samples from a broad range of sites over 3–8 visits to homes with (7) and without (8) CF patients.ResultsTwenty-eight percent of sampled drains yielded P. aeruginosa at least once, and a general mixed linear model estimated that 6.3% of samples from drains yield P. aeruginosa. This is more than eight times the estimated recovery from any other type of household environment.ConclusionsThese findings implicate drains as important potential sources of P. aeruginosa infection. They suggest that maximizing P. aeruginosa control efforts for drains would reduce exposure with minimal extra burden to CF patients and families.