Production of creatinine by bacteria

Very little work has been done to determine whether creatinine is produced by bacteria growing on media free from creatin and creatinine. Germán, 1 in a brief review of the literature on this subject, makes mention of only three contributions. In his paper, Germán gives the result of an investigation of thirty-five species of bacteria to determine whether they were able to produce creatinine. In summing up, he says that this characteristic might be of value in the differentiation of closely allied species.

Our work was undertaken to ascertain: (1) Whether creatinine production is of any value in the differentiation of groups of closely allied species; (2) to determine the method best suited for studying creatinine production by bacteria; (3) to ascertain what amounts of creatinine were produced so that certain quantitative studies might be undertaken.

A medium composed of 2 per cent. Witte's peptone and .5 per cent. salt furnishes a creatin and creatinine free medium. Twenty-eight strains of bacteria, belonging to the mucosus capsulatus group of microorganisms, including B. rhinoscleromatis, B. ozana and B. lactis aerogenes, were grown on the above medium for eight days. Ten cubic centimeters were then tested for creatinine by Weyl's method (adding several C.C. of a 10 per cent. NaOH solution and several drops of a freshly prepared sodium nitroprusside solution, a positive reaction being indicated by the immediate appearance of a dark red zone which soon turns to a greenish color) and 50 C.C. were tested by the Folin method (adding 7.5 C.C. saturated picric acid solution and 2.5 C.C. sodium hydrate, a positive reaction being indicated by the production of an orangered color similar to the color produced by a potassium bichromate solution).