Ecological investigation on intestinal bacterial flora of patients nursed in protected environmental units.

The present results of investigations performed on fresh fecal samples from a healthy adult and subjects with acute leukemia cultured bacteriologically using both aerobic and anaerobic techniques have led to the following conclusions. 1) In studies on the intestinal bacterial flora of the subjects examined, obligate anaerobic bacteria rather than facultative anaerobes accounted for more than 99% of the microorganisms. 2) Although some qualitative differences seem to exist between fecal bacterial flora components of the normal individual and leukemia patients examined, further investigations considering various factors controlling and influencing the composition of intestinal bacterial flora are needed to evaluate the results obtained. 3) The results obtained herein indicate that changes in intestinal bacterial flora induced by non-absorbable antibiotics are associated with the host defense mechanisms. 4) The relative predominance of aerobic versus anaerobic bacterial flora in the intestine may reflect the degree of severity of clinical manifestation in leukemia patients. In the data obtained from the present investigations, the predominating fecal anaerobic bacteria may serve as a base line for the evaluation and interpretation of the host defense system by patterns of the components of bowel flora brought about by internal or external environmental changes.