[Trials to improve the media used for the methyl red reaction (MRT). II].

The evolution of the methyl rot reaction (MRT), expressed by the pH dynamics in the first 18 hours was examined. A medium made of caseine or soya hydrolysate distributed in small volumes, was experimented versus a control broth made of meat peptone (Clark-Lubs). For Klebsiella the results showed that in the control group the pH acidifies and remains low, thus mimicking a positive reaction.

[The effect of the type of peptone for protein catabolism and realkalinization in Klebsielleae cultures].

According to the authors of the present paper, the formation of the MR+ and MR- groups is not explained by the variable degree of acidification, but by the various capacity of realkalinization of cultures. pH increases to values tending to 8 due to the formation of amines, ammonia and other basic products. They are the result of oxidative degradation processes, thus explaining the dependence on oxygen and the strictly aerobic character of the reaction.

[Aerobic conditions and the dynamics of the methyl red reaction in Klebsielleae].

The development of the methyl red reaction (MR) in Klebsielleae, analyzed during a 4-day thermostatting, showed important pH-variations. Two steps are distinguished during the reaction dynamics: the former of acidification, common to all Enterobacteriaceae and the latter of alkaline reversion, specific to Enterobacter, Klebsiella, Serratia and other MR germs. The processes determining the alkaline reversion are conditioned by the presence of large amounts of air/oxygen (aerobic processes).