The Effects of X-Rays on a Strain of Eberthella typhosa

Abstract

A strain of Eberthella typhosa, recently isolated from the blood of a typhoid patient, was exposed to X-rays of maximum characteristic radiation of 0.712 A. Suspensions of the organisms were used and the tubes containing the suspensions were held against the window of the X-ray machine. Pour agar plates were made after each exposure. There was a logarithmic order of death. After 4l/2 hrs. no organisms survived. However, some of the organisms still remained motile but were incapable of producing a colony on appropriate media. Colonies picked from pour plates prepared after 4 hrs. of exposure were studied for the following aspects: colonial character on agar and gelatin; morphology and stain by Gram''s method; fermentation of lactose, glucose, and xylose; lead acetate production; indole production; growth on potato; and motility. The results of these tests were the same as those of the parent culture with one exception. After one exposure many of the organisms picked showed a loss of motility and a change in colony formation from smooth to intermediate form. The results of other tests carried out on these nonmotile organisms were the same as the control organism.