OBSERVATIONS ON THE PERSISTENCE OF COLIFORM BACTERIA IN THE INTESTINES OF INFANTS AND NEWBORN BABIES: ON ORAL ADMINISTRATION WITH A SPECIALLY "LABELLED" STRAIN

Abstract

In order to make experimental studies of the mechanism of the infection and manifestation of intestinal bacterial diseases which may be regarded as fundamental for the studies of bacteriological physiology of the intestines, we made 4 coliform strains selected at random resistant against streptomycin and compared their biological and immunological characters with those of their original strains.We gave the coliform bacteria resistant against streptomycin (L.S.) to newborn babies and infants and observed their persistence in their intestines by cultivating these bacilli in their feces on Endo medium Containing 1000γ per c.c. streptomycin.1. L.S. was orally administered to 73 newborn babies and infants under various conditions and its attitudes as to its growth and persistence in the intestines were persued.2. L.S. which was given to 19 newborn babies persisted in the intestines for a relatively long time, namely, for more than 10 days, in 16 cases. The conditions of intestinal flora in these newbon babies before L.S. was ingested seemed to be the only factor that decided persistence in the intestines.3. In 35 infants of the first group, the ingested L.S. were observed to proliferate transiently for the first one or four days and then disappear in a short time. In two cases of four patients with diarrhea, L.S. showed a weak tendency to persist in their intestines.4. On the other hand, in eight infants of the second group, L.S. ingested with streptomycin showed an increase in persistence. This result was almost the same with that in the newborn described above.5. With seven infants of the third group, when the L.S. in their feces wes found gradual decrease in number, administration of streptomycin prolonged its persistence. This result suggests that by creating a certain artificial condition in the intestines a carrier state of any non-resident coliform bacteria can be produced quite similar to that of dysentery bacteria.6. Artificial replacement of resident coliform bacteria in an indiv dual caused no clinical symptom at least in our experiment if no other factor is present. It is also interesting fact that four patients with diarrhea, though injested with L.S., did not show any increase in diarrhea, but there was some improvement in clinical symptoms. Whether or not natural replacement of resident coliform bacteria in an individual causes diarrhea remains to be studied in the future.We are grateful for kind advices of Prof. B. Nakamura, department of pediatrics and of Prof. D. Ushiba, department of bacteriology. We wish also to acknowledge that this study was supported by the government grant in aid for scientific researches.