[Homogenization of the specimens for culturing mycobacteria by means of the detergents Präwozell N-BX and ditalan E (author's transl)].

In cooperation of four laboratories the efficiency of the two detergents Präwozell N-BX (Nekal BX) and Ditalan E used for homogenization of diagnostic specimens for cultural investigations on tuberculosis was compared. The pretreatment of sputum specimens was done according to the directions given in "DAB 7 (D.L.) - DDR" [German Pharmacopocia 7(Diagnostic laboratory methods) GDR]. Percentage of positive cultures, time of growth and rate of contamination were evaluated. Comparative investigations with both methods using the same sputum specimens were performed with 2117 samples. 245 cultures were positive in all, 223 (91,0%) of them after homogenization by means of Präwozell N-BX and 205 (83,7%) pretreated with Ditalan E. Out of 161 cultures positive with both methods, the time of growth was shorter at least one week in 19 samples (12%) after using Präwozell N-BX and in 55 specimens (34%) homogenized by means of Ditalan E than in the parallel culture. The number of contaminations was 18 (0,85%) after Ditalan E pretreatment and 10 (0,47%) after Präwozell N-BX homogenization. Taking as a basis the directives concerning the cultural investigations for mycobacteria Ditalan E did not show better results than those found with Präwozell N-BX.