A Comparative Study of Various Typhoid O Antigens

Abstract

In view of the increasing interest bacteriologists and clinicians have taken in 0 agglutination in typhoid fever, and the different results 1 , 2 , 3 , 4 , 5 reported with the use of various antigens, it seems worth while to report a comparative study of 3 commonly used 0 antigens in human cases.

Two of the suspensions were prepared from a smooth Rawlings strain of B. typhosus culture, one of which was treated with alcohol according to Gardner's modification of Bien's method; 1 , ∗ the other was cultured in 0.1% phenol broth (Braun 6 ). The third suspension was a formalized suspension of Ty 901 strain (a non-motile B. typhosus) kindly supplied to us by Gardner. The 3 suspensions were not used throughout the study; alcohol and phenol suspensions were used in the first part of the work and alcohol and Ty 901 suspensions in the latter part of the work.

Dreyer's macroscopic agglutination technique was followed in all tests. Incubation was at 56°C. over night. The titre was considered as the highest dilution in which a 2 plus agglutination occurred. All tests resulting in a positive reaction gave a typical granular agglutination. In reporting results only those cases having a titre of 1:160 or above were considered positive.

The results were tabulated into 3 main groups (1) typhoid cases; (2) cases vaccinated with T.A.B., subdivided according to the route of inoculation, subcutaneous or intravenous, since one of us 7 found that this affects the incitement of the 0 agglutinins, (3) all other cases which served as control. Table I gives the results obtained with 427 cases, 239 of which were tested with the alcohol and phenol suspensions and 188 of which were tested with the alcohol and Ty 901. The 3 suspensions did not act similarly in all cases.