腸内細菌巣の変化と気象因子との関連に関する研究

抄録

Since the use of antibiotics to prevent the frequent occurrence of infection by the dysentery bacilli has become widespread, fluctuations of intestinal flora have become a problem. On the other hand, studies on the SS medium used for the culture and isolation of the dysentery bacilli have revealed the mechanism of action of bile acid, the main component of this medium. Thus progress was achieved in the knowledge on the equilibrium of intestinal flora. After F. Kauffmann successfully classified Escherichia coli (E. coli) serologically, detailed studies have been conducted on the movement of E. coli in the intestinal tract. These studies not only solved clinical problems, but also provided the theoretical and experimental elucidation of contamination by the feces. Furthermore, advance was made in defining the physiological and pathological concepts on the bacterial flora surrounding the organism. The author has examined the fluctuation of the intestinal flora based on the concept of health. In other words, the fluctuations of the intcstinal flora as influenced by environmental factors were studied. Climatic factors were considered in the present study. In order to avoid an alteration of the intestinal flora by the action of an invading bacillus, October and November were selected for study. Feces obtained on Tuesday, Wednesday, Thursday and Friday of every week were studied as to the intestinal flora, and the findings were correlated with the climatic conditions of the previous day. Five young male subjects were studied. Fluctuations of the inteseinal flora were judged on the basis of the rate of appearance of E. coli among bacilli of the coli-form group in the feces, the ratio between the E. coli group and enterococcus, and changes in marker E. coli. The intestinal flora was then classified into group A : healthy intestinal flora; group B : fluctuating intestinal flora; and group C : diarrheal intestinal flora. The relationship between these groups and the highest and lowest temperature of the day, daily difference in temperature, humidity, and difference from the temperature of the preceding day was studied. 1. As the maximal temperature of the day becomes lower, the intestinal flora shows more stability. 2. When the lowest temperature of the day is 7-9°C, the intestinal flora is most stable . 3. When the daily difference in temperature is 7-13°C, the most stable intestinal flora is obtained. 4. Fluctuations appeared more pronounced on days with high humidity lasting for many hours. 5. Intestinal flora was unstable when the maximal or minimal temperature of the day dropped by more than 5°C. These observations would suggest that the intestinal flora normally fluctuates, if not pathologically, in response to changes in the outside climate.