[Fundamentals of anti-NADase reaction in A-streptococcus infections and its determination in microtiter test (author's transl)].

A-streptococci of known serotypes were investigated for their ability to produce NADase. For this, a microtiter-dilution technique was employed. The results were compared with those of Lazarides and Bernheimer who had determined the NADase-activity in an other way. It seems, that there is no fixed relation of NADase-production and growth curve for all of the strains. At the moment, anti-NADase can be determined only with a macrotechnique, which is, with respect to costs, time work and others, difficult to handle. A microtiter-technique is described, which is adapted to the macrotechnique. With 426 young men in the age of 18-20 years titers were found between less than 50 and 800 with a 95% level between 200 and 300. The reproducibility of the micromethod is like that of the macromethod. It is of great importance to redetermine the titer in the upper limit of normal and those which are expected to rise. The possibility to seize also infections with G- and C-streptococci is mentioned.