Impact of Lactobacillus acidophilus supplements on the human oropharyngeal and intestinal microflora

The influence of Lactobacillus acidophilus supplements on the oropharyngeal and intestinal microflora was studied before, during and after L. acidophilus administration. 10 healthy volunteers participated in the study. L. acidophilus was given as a fermented milk product containing 5 X 10(8)-2 X 10(9) CFU/ml in a dose of 250 ml twice a day for 7 days. Only minor changes in the number of aerobic and anaerobic microorganisms in the oropharynx were observed, with no increase in the number of lactobacilli. In the aerobic intestinal microflora a decrease in the number of Escherichia coli was observed in 6/10 subjects. Concerning the anaerobic intestinal microflora there was a significant increase in the number of lactobacilli in 9/10 subjects within 7 days of L. acidophilus administration. The increase in the number of lactobacilli remained as long as the subjects were consuming the L. acidophilus preparation. Lactobacilli returned to the same level as before the study 9 days after the L. acidophilus administration was stopped. Anaerobic cocci showed a decrease in 4/10 subjects, while the number of other anaerobic bacteria remained relatively constant throughout the observation time. These studies suggest that L. acidophilus in this type of preparation should be taken continuously in order to maintain high levels of lactobacilli in the intestine.