[Model trials for isolation of soft rot bacteria by media containing pectic substances (author's transl)].

1. Under aerobic conditions bacterial soft rots are caused in the most cases by pectolytic Erwinia, Pseudomonas, and Bacillus spp. 2. Using 7 soft rotting strains several selective media were tested for their ability to sure a quick and exact isolation and differentiation of these pathogens. By bile salt-lactose-medium all Erwinia spp. under test could be isolated. For isolation of pectinolytic Pseudomonas strains the D4 medium of Kado and Heskett was suitable as the best one. 3. By the use of substrats containing pectic substances the results of isolation could be essentially improved: So, a sure differentiation of soft rotting bacteria and saprophytic organisms already upon the substrate and in addition, the isolation of pectinolytic Bacillus strains also became possible. The pectinolytic activity of the test strains on pectin-double layer-media was dependent upon the composition of the basal medium. 4. On the base of the results we obtained an isolation scheme is proposed, that allowed to indicate the pectolytic active bacilli (after heating to 80 degrees C for 10 min) on thioglycollate medium covered by a pectin layer, the Erwinia spp. on Stewart-Medium covered by pectin layer and the pectolytic pseudomonads on FPA-medium described by Sands, Hankin and Zucker (containing citrus pectin) to the equal time. 5. The trials also demonstrated, that the preparing of double layer-media instead of sodium polypectate mostly being recommended in literature lower estered pectic compounds can be used successfully.