Selective localization and growth of Bifidobacterium bifidum in mouse tumors following intravenous administration.

A strain of domestic bacteria, Bifidobacterium bifidum (Lac B), which is nonpathogenic and anerobic, selectively localized and proliferated in several types of mouse tumors following i.v. administration. None of the same bacilli could be detected in the tissues of healthy organs such as the liver, spleen, kidney, lung, blood, bone marrow, and muscle 48 or 96 hr after i.v. administration into tumor-bearing mice. Proliferation of Lac B in the tumor was artifically stimulated by i.p. administration of DDD-H-2s mice of a synthesized disaccharide, lactulose (4-O-beta-D-galactopyranosyl-D-fructofuranose), a sugar which is not metabolized by mammalian tissue cells. Lac B, which survices and proliferates selectively in the tumor following i.v. administration into the tumor-bearing host, should aid in diagnosis and selective therapy for cancer.