Air Sampling for Legionella-Reply

In Reply.—  In their letter, Dr Zingeser and colleagues have provided further evidence that detection of the causative agent by air sampling complements epidemiologic investigations of legionnaires' disease. Since legionellae are widely distributed in water, the significance of isolating the bacteria from water reservoirs of aerosol-producing devices is often uncertain¹; however, we suspect that legionellae are not frequently present in air. In our JAMA study, which associated legionnaires' disease with shower use, legionellae were isolated after, but not before, water was turned on in a shower. In another investigation associating legionnaires' disease with exposure to one area of a building in close proximity to a device that produced contaminated aerosol, legionellae were isolated from air samples collected in that area, but not in other areas of the same building unexposed to the contaminated aerosol.² Thus, using selective air sampling to detect legionellae within respirable-sized droplets in aerosols