Sulfuric Acid and Streptococci Clearance From Respiratory Tracts of Mice

The inhalation of 15 mg/cu m (3.2mu count median diameter) of H2SO4 aerosol for four hours after exposure to radioactive aerosol resulted in a reduction in the rate of clearance of nonviable streptococci from the lungs and noses of mice. A second exposure to H2SO4 lasting 90 minutes (15 mg/cu m, 3.2mu count median diameter) for four days prior to the radioactive aerosol resulted in a reduced rate of clearance of nonviable streptococci from the noses but not the lungs. Neither of these exposure regimens caused an alteration in the rate of reduction of viable streptococci from the lungs or noses. Inhalation of 1.5 mg/cu m of H2SO4 (0.6mu coung median diameter) for four daily 90-minute exposures prior to, or for four hours after exposure to Streptococcus caused no alteration in the normal rate of clearance of viable or nonviable streptococci from the noses or lungs.