Abstract
Mycobacteriophage B04 grown on the indictor host strain M. fortuitum SN203 was restricted and modified by M. tuberculosis H37Rv. Phage B04 .cntdot. H37Rv was restricted and modified by the alternate host SN203. M. tuberculosis strain Myc 1025 was described as a r-m- isolate. Using the mycobacterial prototype strains for phage typing wild M. tuberculosis isolates, only the modified phage B04 .cntdot. H37Rv was a potential type phage.