Since the universe must contain millions of appropriate planets, consciousness in some form - but not with the paired eyes and limbs, and the brain built of neurons in the only example we know - may evolve frequently. But if only one origin of life in a million ever leads to consciousness, then Martian bacteria most emphatically do not imply Little Green Men.
Stephen Jay Gould (1999). “Leonardo's Mountain of Clams and the Diet of Worms: Essays on Natural History”, Three Rivers Press (CA)