Transferable bacteriophage as a function of temperature
Berger, E.; Roesli, H.
Zeitschr Hyg U Infektionskrankh 107(3/4): 731-741
Experiments of Doerr and Gruninger have indicated that Escherichia coli is able to multiply at 43[degree]C., while its transferable bacteriophage does not increase and even disappears after about 7 hrs. These results were questioned by d'Herelle, who suggested that such results might be due to use of acid bouillon or to sugar in the medium, which might have yielded acid through action of E. coli. In the 1st experiment reported in the present paper, the conditions of the Doerr and Gruninger experiment were reproduced, using the same culture, and the same bacteriophage. About 2000 bacteria per cc. at time of inoculation increased to over 1 million in 6 hrs., and bacteriophage was no longer demonstrable after 9 hrs., although bacteria were innumerable. Mention is made of the work of Gjorup, who used the same technic but tested mixtures of E. coli and bacteriophage by the plaque method, tubes being subjected to temp. of 10-45[degree]C. At the lower temp. bacteriophage increase was constant. According to temp., there was a gradual increase, reaching its maximum at 37-40[degree]; at 45[degree] even that bacteriophage present at the beginning completely disappeared. Within the limits of 9.24-6.72, pH had no determining influence. Experiments here reported show that absence of bacteriophage at high temp. is not dependent upon initial concentration, since marked growth of colon bacilli occurred at 48[degree], but no considerable lysis took place in any of the dilutions at 37[degree], even after 8 hrs. The hypothesis that bacterial destruction is the source of production of bacteriphage is questioned, since increases in bacteriophage and bacteria begin at the same time, high concentration of bacteriophage being reached before mass destruction of bacteria begins. Failure of bacterial destruction in fluid gelatin, combined with increase in bacteriophage and its inhibition at 43[degree], are facts opposed to this hypothesis, and it is concluded that bacteriophage is simply unable to increase and function at this high temp. Effect of bacteriophage on the E. coli is due to 2 varia-bles: concentration of bacteriophage and temp. of growth. There is an optimum temp. for bacteriophage, and a maximum temp. beyond which its strongest concentration has no effect. It would appear that the ob-servations of Doerr and Gruninger to the effect that colon bacili at 43[degree] in bacteriophage-containing bouillon can increase without increase in bacteriophage were correct. Under such conditions bacteriophage disap-pears after more than 6 hrs. Thus, the objections of d'Herelle to the findings of Doerr and Griininger are not valid.