Mycobacterium bovis: Polymerase chain reaction identification in bovine lymphonode biopsies and genotyping in isolates from southeast Brazil by spolygotyping and restriction fragment length polymorphism

Diagnosis of the Mycobacterium tuberculosis complex by direct PCR of medias tinal lymphnode DNA and microbiological tests were compared in cattle suspi cious of bearing tuberculous-like lesions detected during slaughter. The PCR procedure applied on DNA samples (n=54) obtained by adding alpha -c asein into the thiocyanate extraction mix was positive in 70% of the sample s. PCR confirmed the identification of 23 samples (100%) that grew in cultu re, 9 samples (60%) that failed to grow in culture, plus 6 (37.5%) samples that resulted in growth of bacterial contaminants. Genotyping by IS61 10-RF LP and DR-spoligotyping analysis of seven samples revealed the presence of several polimorphisms. Seven of the isolates contained multiple copies of I S6110, thus defining the existence of five singular genotypes.