An examination of the microbiologic flora of normal lung of the dog.
We examined the hypothesis that normal lung is sterile. A laboratory animal, the dog, was chosen so that sample size could be maximized. Controls were used to eliminate the possible artifactual presence of bacteria in the lung. Thirty-seven per cent of lung samples contained aerobic bacteria with a mean concentration of 1.3 X 10(3) organisms per g of tissue. Seventy-four per cent of identical bacterial isolates were found in the pharynx of the same animal. We concluded that viable bacteria are aspirated into normal lung where they may survive for at least limited intervals.
D000818:Animals; D001419:Bacteria / Q000302:isolation & purification*; D004285:Dogs; D008168:Lung / Q000382:microbiology*