Microcolony detection of Mycobacterium Bovis in Middlebrook 7H11 thin layer culture

Abstract

The aim of this article is to evaluate the efficiency of the cultivation technique in thin layer of Middlebrook 7H11 (TL7H11) for isolating Mycobactererium bovis from suggestive lesions of tuberculosis in cattle and to compare the results with traditional methods of cultivation. At the first step it was used M. bovis AN5 and M. tubercuolosis H37Rv standard strain. The both performance were compared between the cultivation in TL7H11 and in the Stonebrink and Petragnani media. The strains presented visible growing in TL7H11 at the third day of cultivation, while the Stonebrink and Petragnani there were growing just at the 14 day. At the 13 day of cultivation it was possible to differentiate both strains by their colony morphological characteristics. The second step was to cultivate 62 clinicals samples in TL7H11 and Stonebrink for tentative isolation of M. bovis. The isolated samples were detected in TL7H11 until 21 days of cultivation whereas none samples weregrown in Stonebrink tubes. The median time of growing in TL7H11 was 19,0 days against 49,0 days of Stonebrink (p=0,014).