Typing of Typhoid Bacilli in Nine Western States by Bacterio-phage Method of Graigie and Yen

Abstract

The method of typing various strains of Bacterium typhosum, as reported by Craigie and Yen, has received neither the recognition nor the widespread application that its useful possibilities seem to justify. The survey herein reported was undertaken in an effort to bring the advantages of this method to the attention of those most likely to benefit by its use. The typing method is based on certain peculiarities of a strain of bacteriophage which is specific for the Vi form of B. typhosum. In addition this bacteriophage exhibits a selective affinity for the strain on which it is propagated and for epidemiologically related strains. By selective propagation of this bacteriophage on various strains of B. typhosum, Craigie and Yen have shown that it is possible to divide freshly isolated cultures into a limited number of readily distinguished types, which have been designated by the letter system A to J inclusive, with the exception of type I. Later reports by Craigie, and by Yen have added subtypes of B, D, E, and F and additional studies have brought to light types L and M, which are rarely encountered. Among the typed cultures herein reported, 97.1 % fell into the 6 main groups, A, B, C, D, E, and F. Cultures for this study were obtained through the cooperation of the directors and technical staffs of the 9 state laboratories concerned, and were typed by the method described in detail in the original report by Craigie and Yen. Table I shows the distribution of the various types by states. Table II is included to show the distribution of individual patients by states, since in many cases multiple cultures were received from single individuals.