Quantitative sputum gram stains in chronic bronchial disease.

Abstract

The assessment of bacterial flora of the bronchial system can provide useful information for determining the presence of acute bacterial infections in patients with chronic bronchial disease. The authors examined the value of quantitative sputum gram stains performed in patients during acute bronchial exacerbations, recovery from such exacerbations, acute allergic exacerbations of chronic extrinsic asthma, and a stable period. The mean number of each morphologic type of microorganism was determined for 20 oil immersion fields. Ninety-nine percent of the patients without clinical evidence of bacterial infection had fewer than 16Haemophilus influenzae-like, 10 pneumococcus-like, and 18Neisseria-like microorganisms per gram stain oil immersion field. Even during the recovery period, when the patients were on antibiotics, we noted few gram negative rods, diphtheroid-like, or staphylococcus-like microorganisms on gram stain. The data indicate that upper limits may be set for numbers of microorganisms seen on gram stain in the absence of clinically apparent acute bacterial infection in chronic lung disease.