Evaluation of fetal bovine serum as a source of enrichment in synthetic culture medium for the isolation of Mycobacterium bovis

Abstract

A Middlebrook 7H10 medium added with 0.2% glucose and Fetal Bovine Serum (FBS) at concentrations of 5, 10, and 15% was compared with a Middlebrook 7H11 medium enriched with commercial OADC to evaluate the growth of Mycobacterium bovis, strain AN5, in the dilutions 10-1, 10-2, 10-3 and 10-4 performed from the McFarland scale 1. The results demonstrated micro and macroscopic growth of mycobacteria in all concentrations of SFB two weeks after inoculation, and in greater numbers when compared to Middlebrook 7H11 supplemented with commercial OADC. Statistical analysis found a significant reduction in the Middlebrook 7H11 group when compared to the 15% SFB concentration group in dilutions 10-2, 10-3, and 10-4. The results presented allowed us to conclude that FBS can be used as a source of enrichment for a Middlebrook 7H10 Medium in a thin layer, for isolation of Mycobacterium bovis, with the advantage of being more accessible and cheaper than the commercial medium.