[Microbiologic studies of the lung clearance of rats after aerogenous long term exposure to ammonia]

The effects of aerogenic long-time exposure of 1,990 female Wistar rats to 30, 50, 100 and 150 nl/l of NH3 for 3, 14, 28 and 42 days on clearance of inhaled bacteria (Staphylococcus aureus, SG 511 strain) were studied together with effects on the clinical condition and behaviour of these test animals. For concentrations below 100 nl/l, action upon pulmonary clearance was found to depend above all on the length of exposure, whereas effects of 150 nl/l proved to depend more strongly on concentration. All concentrations tested tended to act on pulmonary clearance in the form of increased numbers of bacteria which remained in the lungs of the experimental animals. Clinical symptoms attributable to NH3 action were not recordable.