Action of the Bacteriophage on a Thermophilic Bacillus.

Abstract

Of the various species of bacteria which have been found susceptible to the action of the lytic principle or bacteriophage, 1 it is noteworthy that all are types which have their optimum temperature for growth at 37° C. or lower. It seemed of interest, therefore, to determine whether organisms capable of growth at high temperature—the thermophiles—would also be susceptible to the action of the lytic principle. Efforts to obtain a “thermophilic bacteriophage” have been successful and a preliminary report will be given here.

The organism employed in these experiments was one of the stock collection of thermophiles maintained in this laboratory. It was isolated originally by Tanner and Harding 2 from milk, and has been carried in stock under the designation T60. It is a medium-length, slender, Gram-positve rod, forms spores, and stains readily by the ordinary dyes. The culture is capable of growth at all temperatures from 20° to 60° C., the optimum appearing to be from about 45° to 52° C., at which point growth is very rapid and more luxuriant than at 37°. At room temperature a moderate growth develops after 2 to 3 days.

From sewage polluted river water an active lytic principle was obtained against this organism by employing the usual method of alternate feeding and filtration. The incubation temperature during this process was always 37° C. After developing a lytic filtrate at this temperature it was found to be very active, without any gradual adaptation to a higher temperature, when brought in contact with a homologous culture growing at 52° C. The lytic principle was transmissible through series of broth cultures, one series was held at 37°, the other at 52° C.