Mycobacterial Interspersed Repetitive Unit-variable Number Tandem Repeat (MIRU-VNTR) Typing Lacks Discriminatory Power in the Genetic Analysis of Bovine Tuberculosis in Egypt

Tuberculosis (TB) is one of the most important infectious zoonotic diseases of vertebrates worldwide. TB in animals is primarily known from cases in cattle and other bovids for which the disease is generally referred to as bovine TB. The major causative agent of bovine TB is Mycobacterium bovis (M. bovis), a member of the Mycobacterium tuberculosis complex. Animal TB is a disease of high economic relevance within the context of livestock farming as it directly affects animal productivity and also influences international trade of animal products. In this study, we aimed at mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis of cases of TB infection in local cattle in Egypt. Therefore, various samples (milk and blood samples) were collected from cattle farms (in Damietta Province) that were positive for tuberculin test. Mycobacterial isolation was tested on milk samples, but it showed negative result. DNA was extracted from blood samples. Five mycobacterial genes (IS6110, katG, gyrA, oxyR, pncA) were used for further confirmation of field TB infection. All blood samples were positive for Mycobacterial-specific genes. Twelve MIRU-VNTR loci were used to test their discriminatory power in the genetic analysis of TB, but such MIRU-VNTR loci typing failed to show any discriminatory power for the genetic analysis of bovine TB cases.