Bovine tuberculosis (bovine TB, bTB) is caused by bovine bacilli: and The studies conducted in Poland, in the National Bovine Tuberculosis Reference Laboratory in the Department of Microbiology of the National Veterinary Research Institute in Pulawy, show that animal tuberculosis in Poland is also caused by We here describe the identification and genotypic assessment of 52 isolates of obtained from Polish cattle and wild animals over the last five years. We show that strains isolated from bison have significant genotypic diversity and are distinct compared with the genotypes of strains isolated from cattle. Similarly, isolates from cattle herds can be highly genotypically variable. Formal designation of the members of the complex is controversial in Poland; there is a gap in veterinary legislation with regard to bTB and no explicit mention of causing tuberculosis in animal.