ABCG2 and tuberculosis: Furthermore, although M. smegmatis and other pathogenic species (except M. leprae) have a greater number of ABC transporters than MTBC, they do not include the UgpAEBC system (revised in Transport DB 2.0), suggesting this transporter can be related to the uptake of substrates only available in Mycobacterium species that cause tuberculosis or tuberculosis like diseases.