The isolation and serological differentiation of bacillus tetani

As the history of bacteriology has shown that conditions regarded as clinical entities may be caused by a number of different organisms, it seemed of importance to determine whether theBacillus tetani is an individual micro-organism, or whether there are several organisms differing from one another, but all capable of elaborating a spasm-producing toxin. This enquiry involves the demarcation of the tetanus bacilli from similar organisms and their differentiationinter se , by serological methods. By employing the agglutination reaction it can be shown that there are at least three serological types ofB. tetani . One of these, which may be designated Type I, has hitherto been almost exclusively used for the preparation of antitoxin, and, so far as is known, such antitoxin protects against the toxin of all three types. The results obtained in the present investigation suggest that this is only partially true, as the types ofB. tetani isolated from cases of the disease do not correspond serologically with the type in common use for the preparation of antitoxin. This question is still under consideration, as the number of cultures so far examined is too limited to permit of far-reaching conclusions being drawn from the work done. In attempting to isolate numbers of strains ofB. tetani it is found that there are frequently present in the wounds of men suffering from tetanus, bacilli which have morphological characters so like those ofB. tetani that they might readily be mistaken for that organism. Serological investigation of these (non-toxic) micro-organisms, which might be referred to as tetanoid bacilli, shows that they too constitute a group, the members of which can be differentiated one from another by serological methods.