COMPARISON OF 2 METHODS FOR ISOLATION OF MYCOBACTERIUM-PARATUBERCULOSIS FROM BOVINE FECAL SAMPLES

  • 1 July 1989
    • journal article
    • research article
    • Vol. 50  (7) , 1110-1113
Abstract
Fecal samples from 131 cattle clinically suspect for paratuberculosis were cultured bacteriologically, using the traditional sedimentation processing method and a processing method that included a centrifugation step. Of 16 samples that were contaminated, 6 were culture-positive on at least 1 medium and by 1 processing method. Ten of 131 (7.6%) fecal samples processed by both methods were lost because of contamination. The number of culture-positive samples (using both processing methods) were 65 of 121 (53.7%) on media without miconazole and 60 of 121 (49.6%) on media with miconazole. Seven of the 121 (5.8%) samples were culture-positive, using centrifugation, after 16 weeks'' incubation at 37 C. Thirteen of 60 (21.7%) isolates were obtained only with centrifugation, and 10 of these had low colony counts, suggesting that a centrifugation step may have concentrated microorganims that would have gone undetected without centrifugation. Six of 60 (10%) isolates positive for Mycobacterium paratuberculosis on the sedimentation method were negative on the centrifugation method. Contamination rates were significantly (P < 0.001) increased when centrifugation was used. The miconazole significantly (P < 0.001) decreased contamination rates when centrifugation was used.