A Biochemical Study of Proteus Vulgaris

In this study we deal with the cultural properties, the products of growth, the pathogenicity, and the toxicity, of two strains of Proteus vulgaris, Hauser. This is an exceedingly interesting organism on account of its wide distribution, the ease with which it is modified, and because it seems to stand between the true saprophytic and the purely pathogenic bacteria. It has been found under a great variety of abnormal conditions in the human body, but most frequently in the digestive tract, where it produces the greatest harm. Here it has been present in large numbers, in a variety of food poisonings (1, 2)F2 in the summer diarrheas of children (3, 4), the diarrheas of calves (5), in severe cases of typhoid fever (6), and in other more obscure abnormal intestinal conditions. Its association with other pathogenic organisms is of great importance and probably has not received the attention it deserves. Theobald Smith (7) found that when the hog cholera bacillus and Proteus were grown together, in what he called a mixed pure culture, the virulence of the former was lowered, while that of the latter was apparently raised. Ktihnau (8) found virulent strains of Proteus in severe cases of diphtheria. Levy and Thomas (9) find that the virulence of the cholera spirillum was raised by injecting cultures of Proteus precipitated by alcohol. Its presence in severe cases of typhoid has already been mentioned (6) and in the same article Vincent notes that mixed cultures of Proteus and the typhoid bacillus are very virulent for rabbits.