A recombinant bacterium capable of reducing tumor growth is provided, wherein said recombinant bacterium is capable of: a. increased expression of a nucleic acid encoding a chemoreceptor that directs chemotaxis towards tumors, b. accumulation in a quiescent tumor, c. hyper-invasion of a tumor, d. reduced fitness in normal tissue, e. enhanced stimulation of the host innate immune responses, f. delivering a tumor specific DNA vaccine vector to a tumor cell, and g. increased bacterium-induced host programmed cell death.