Dr Behr employs bacterial genetic methods to study the epidemiology and pathogenesis of mycobacterial diseases. In conjunction with public health investigators, he uses molecular biology to create DNA fingerprints of bacteria, allowing to better track the spread of organisms within the community. This combination is known as molecular epidemiology. As well, he determines the genetic differences between closely related organisms in order to understand the reason why some cause disease and others are less virulent. A variety of genetic techniques are used, including PCR, DNA microarrays and whole genome sequencing to uncover the molecular differences within the Mycobacterium tuberculosis complex, between subspiece of Mycobacterium avium and across the Mycobacterium genus.