[Standardization of the direct hemagglutination reaction induced by bacteria of the genus Lactobacillus]

L. bulgaricus, L. casei var. rhamnosus, and L. plantarum cells grown in agar-containing (but not liquid) thioglycol medium for 3 days have been shown to be capable of inducing mannose-resistant agglutination of human and guinea-pig erythrocytes, while giving a considerably weaker reaction with erythrocytes from animals of other species (ox, sheep, dog, rabbit, rat and mouse). The optimum conditions for the test are presented.