Study on Microflora of Human Intestine
I. The Alteration of the Constitution of Intestinal Flora by Oral Administration of L. Acidophilus Strain Shirota to Healthy Infants
1966 Volume 21 Issue 5 Pages 274-283
Details
1966 Volume 21 Issue 5 Pages 274-283
50ml of fermented milk, containing 1 to 2×108/ml of live Lactobacillus acidophilus strain Shirota (LAS) and 180ml of market milk were orally administration daily to healthy infants (2-6 years) for 35 days, and its effect on the constitution of microflora in feces was investigated, using appropriate selective media.
In control group, normal microflora in one gram of feces was found to consitute of 108-1010 of Bifidobacterium classified to three physiological type, 106-109 of enterobacteria group in which E. coli was predominant, 103-105 of lactobacillus group consisting of 60% of L. acidophilus and other lactobacilli (L. plantarum, L. casei and heterofermentives), 104-107 of enterococci, and 10-104 yeasts.
During the first 7 days of adminstration, lactobacillus in feces increased to 106-108/gram and this level persisted during the whole administration period. This lactobacillus was serologically identified to be LAS. In contrast, enterobacterial group and enterococci decreased by a facter of 1/100 and 1/50, respectively. When administration was stopped, LAS decreased gradually and one to two weeks after became undetectable, while the suppressed groups recovered to original level. Concomitant with this change, the pH of the feces rised from 5.0-7.5 to original value, 6.7-8.7. Other members in feces were not siginificantly affected through the period of experiment.
These results led to the conclusion that LAS survives in human intestinal tract though it does not establish permanent residence, and alter the consititution of microflora, being especically antagonistic against E. coli and enterococci. The antagonistic activity of LAS is discussed.
