Predatory Bacteria in Pathogen Control

Predatory bacteria are a specialised group of Gram-negative microorganisms that locate, invade or attach to susceptible prey bacteria and consume them from within or without. These predators, typified by species such as Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus, hold promise as living antibiotics against multidrug-resistant pathogens. Their life cycle often comprises an extracytoplasmic “attack” phase during which they seek prey, followed by a reproductive phase within a prey-derived niche. Predation can proceed by periplasmic invasion, in which the predator enters the prey’s cell envelope and digests its contents, or by epibiotic attachment, in which lytic enzymes degrade the prey surface externally. Both modes lead to rapid reduction of target populations. Beyond direct pathogen clearance, predatory bacteria can work in concert with host immune defences to enhance infection resolution. Research has also broadened the prey range to include Gram-positive organisms through secreted proteolytic systems. Field and laboratory studies have demonstrated predatory efficacy in diverse environments, from the gut microbiota to the respiratory tract, and pointed to a favourable safety profile in mammalian hosts. Advances in genomics, cell biology and enzyme characterisation are now driving efforts to harness these organisms or their molecular machinery as novel biocontrol agents, with potential applications in medicine, agriculture and environmental management.

Research from Nature Portfolio

Recent work has uncovered a new example of predation beyond the traditional Gram-negative targets: a marine Pseudoalteromonas strain employs a metalloprotease secreted via a Type II secretion apparatus to bind and degrade the peptidoglycan of diverse Gram-positive bacteria. This interaction releases nutrients that fuel predator growth and suggests that predatory dynamics in natural communities are broader than previously recognised. The study also identified that gene clusters encoding proteolytic effectors are widespread among marine bacteria, indicating a conserved strategy for biocontrol in aquatic ecosystems.

Another study evaluated the in vivo safety of obligate predatory bacteria when administered to a mammalian host via respiratory and intravenous routes. The predators induced a transient, low-level inflammatory response but caused no lasting tissue pathology or adverse effects on host viability. Quantitative analyses showed that predatory cells were rapidly cleared by host mechanisms. These findings support the feasibility of using live predatory bacteria or their derivatives as therapeutic agents against antibiotic-resistant infections.

Research from all publishers

A comprehensive review of Bdellovibrio bacteriovorus cell biology has detailed how its chromosome architecture and replication dynamics are remodelled during the transition from attack to growth phases. The study elucidated the spatiotemporal coordination of DNA replication with predator differentiation, revealing regulatory circuits that could be harnessed to optimise predation efficiency or tailor predator behaviour in applied settings.

Another synthesis of the field has highlighted the diverse secreted enzymes of predatory bacteria and their biotechnological potential. This work catalogued a range of peptidoglycan hydrolases, proteases and other lytic factors, and discussed strategies for enzyme purification, recombinant production and formulation. It also explored applications in bioremediation, animal health and crop protection, emphasising how predation mechanisms can be decoupled from live-cell deployment to create enzyme-based antimicrobials.

Predatory Bacteria in Pathogen Control publication trend

The graph below shows the total number of articles in predatory bacteria in pathogen control across all publications each year (not limited to Nature Index journals).

Technical terms

Periplasmic predation: A mode of predation in which the predator invades the space between the outer and inner membranes of a Gram-negative prey, digesting its contents from within.

Epibiotic predation: A foraging strategy whereby the predator remains outside the prey cell envelope and secretes lytic enzymes to degrade the prey surface.

Type II secretion system: A multi-protein complex in Gram-negative bacteria that transports folded enzymes and toxins across the outer membrane into the extracellular milieu.

Peptidoglycan: A polymeric mesh of sugar chains cross-linked by peptides that forms the rigid cell wall of bacteria and serves as a target for predatory enzymes.

References

1. Chromosome structure and DNA replication dynamics during the life cycle of the predatory bacterium Bdellovibrio bacteriovorus. FEMS Microbiology Reviews (2023).
2. Biotechnological Potential of Bdellovibrio and Like Organisms and Their Secreted Enzymes. Frontiers in Microbiology (2020).
3. A predator-prey interaction between a marine Pseudoalteromonas sp. and Gram-positive bacteria. Nature Communications (2020).
4. Examining the safety of respiratory and intravenous inoculation of Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus in a mouse model. Scientific Reports (2015).