Effect of predatory bacteria on the gut bacterial microbiota in rats.
Shatzkes K, Tang C, Singleton E, Shukla S, Zuena M, Gupta S, Dharani S, Rinaggio J, Connell ND, Kadouri DE
Sci Rep. Mar 2017. doi: 10.1038/srep43483
COMMENT: There is a big problem with multidrug resistant bacteria. Different approaches could be useful and one of this is the use of predatory bacteria and among them Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus. Both of them are Gram-negative and obligate predators of other Gram-negative bacteria.
Bdellovibrio bacteriovorus is a Deltaproteobacteria that uses a type IV pilus to attach to a prey cell and invade it and then lives in the periplasm of the prey. When the nutrients are exhausted, the invader divides and lyses the prey to find new preys.
Micavibrio aeruginosavorus is a ‘vampire-like’ bacteria attaching to the prey cell outer membrane to leach nutrients from the outside.
There is evidence that predatory bacteria may already be present in healthy human flora. Multiple studies have detected B. bacteriovorus within the gut and oral microbiomes of humans and other animals.
To date, it has been demonstrated in vitro the ability of these bacteria to combat some pathogens and the authors analyze the effects of introducing predatory bacteria into a live host digestive tract and the effect over the Microbiome.
The authors show that the introduction of predatory bacteria into the rat gut does not seem to cause pathological effect or to provoke a robust inflammatory response within the gastrointestinal tract and propose a possible use of predatory bacteria as antimicrobials.
The authors conclude that:
The results suggest that introducing predatory bacteria into the rat gut does not result in any measurable adverse pathological effects and does not cause a substantial immune response within the gut. Furthermore, the limited changes in gut bacterial populations due to intrarectal inoculation of B. bacteriovorus directly into the gastrointestinal tract were mostly associated with healthy benefits, while potential adverse negative effects were seen in microbiota changes due to M. aeruginosavorus.
With the increased prevalence of antibiotic resistant infections, this study provides further support for developing predatory bacteria into a novel antimicrobial treatment. Future studies will focus on further understanding how predatory bacteria are removed from the gut by the immune response, as well as increasing sequencing depth to further decipher changes in the microbiota at the species level due to administration of predatory bacteria.