INHALATION therapy equipment is frequently contaminated with bacteria, as illustrated in the references quoted in the preceding paper.1 The importance of this contamination has been shown by a number of reported outbreaks of serious disease in pediatric patients, which have been traced to organisms which characteristically grow in water or which were found in the water or equipment after the outbreak (Table 1).2-13 However, there is very little data on the risk of colonization or infection of infants exposed to mists contaminated with bacteria.
At the time this study was begun, it had just been recognized that the fresh distilled water used in inhalation therapy equipment, which had been presumed to be sterile, contained small concentrations of bacteria. Previous testing of this water using 0.01-ml samples had indicated no bacterial growth, but larger inocula of 0.5 ml of water in 10 ml of broth regularly showed bacterial contamination,