Bdellovibrio bacteriovorus

Bdellovibrio bacteriovorus is a bacterial shark—a tiny, fast-swimming predator that hunts, kills, and consumes other bacteria. Unlike myxobacteria's cooperative swarming predation, Bdellovibrio hunts alone, using its single polar flagellum to swim at remarkable speeds (up to 100 cell lengths per second) until it collides with prey. Upon contact, Bdellovibrio penetrates the prey cell wall and takes up residence in the periplasmic space, where it consumes the prey from within before dividing and releasing progeny to hunt again.

The predatory lifecycle requires exquisite targeting. Bdellovibrio must distinguish prey bacteria from non-prey and from each other. It must attach, penetrate, and establish within prey cells without triggering fatal host responses. Once inside, it must extract nutrients efficiently while avoiding premature prey cell lysis. This complex lifestyle—essentially parasitism with cell consumption—represents one extreme of bacterial ecological strategies. Where myxobacteria overwhelm prey through numbers, Bdellovibrio overwhelms through precision.

Bdellovibrio has attracted attention as a potential 'living antibiotic.' It kills many Gram-negative pathogens, including antibiotic-resistant strains, and cannot attack human cells. Unlike conventional antibiotics that exert selection pressure for resistance, Bdellovibrio predation may be harder to evolve resistance against—prey must escape an actively hunting predator, not just neutralize a static chemical. Clinical development faces challenges, but Bdellovibrio demonstrates that biology offers antimicrobial strategies beyond antibiotics.