Toxic Bacteria Devours Tumors With Precision

A stained dog tumor treated with the bacterium. Lighter pink areas areas denote tumor death. Credit: David L. Huso and Baktiar Karim of the Johns Hopkins Department of Pathology A bacterium found in soil that can cause flesh-ravaging infections in its natural state has been converted — with a few genetic tweaks — into a precise tumor assassin. Researchers from the Johns Hopkins Kimmel Cancer Center excised the toxin-producing gene from the bacterium Clostridium novyi, which, in its natural form, can be fatal when introduced to the bloodstream. They injected spores of the modified bacteria directly into tumors of mice, dogs and ultimately a human patient. In all three cases the spores germinated and released enzymes that ate the tumor from the inside out, resulting in either a significant reduction in tumor size, or complete eradication, without damaging healthy tissues. Scientists say that with this proof of concept the prospects for bacterial injection therapy, as a treatment in combination with anti-cancer drugs, has vastly improved.