It’s Halloween! This time of year many of us revel in all things spooky, huddle by a cozy fire and share chilling tales of our favorite monsters. Embracing the eerie ambiance of the season and the looming specter of fearsome creatures, I’ve embarked on a journey to delve into the enigmatic world of eerie bacteria that live within us. The microbiome, an intricate tapestry woven from trillions of bacteria, viruses and fungi, conceals a microbial species that bears an uncanny resemblance to iconic monsters such as zombies, vampires and werewolves.

‘Zombies’ in the gut

A recent study examines how bacterial metabolites can activate dormant zombies within our gut. The gut is a bustling battleground where countless bacteria, fungi and viruses vie for their survival and territory.

One strategy used in this microbial warfare involves a chemical called colibactin, which is produced by specific strains of E. coli bacteria. When released, colibactin can cause DNA damage to nearby bacterial cells, which could create an environment that makes it easy for E. coli to survive. Colibactin can potentially wake up dormant viruses within our bacterial cells, leading to a state resembling a zombie scene in “The Walking Dead.” Colibactin has been associated with the development of colorectal cancer.

Researchers are looking at how colibactin activates or wakes up these viruses and are exploring strategies to fight cancer.

‘Vampire’ bacteria

Bdellovibrio bacteriovorus is known as the “vampire bacteria.” It thrives in various environments, including the human gut. These bacteria are famous for being the tiniest, yet deadliest, hunters. When the vampire bacteria finds their host—usually another kind of bacteria—they attach to the host’s outer membrane, penetrate the cell and reproduce, all while consuming the host’s nutrients. Ultimately, the vampire bacteria rupture the host cell, liberating their newly replicated offspring, which can then go on to infect other cells.

Researchers are very interested in studying B. bacteriovorus for its potential to combat bacterial infections and promote microbiome health.

Microbial ‘wolf pack’

Another captivating predatory bacterium called Lysobacter acts like a pack of wolves. This microbial “wolf pack,” as it’s sometimes called, glides through the body and uses enzymatic “fangs” to break down and consume other microorganisms. This predatory behavior is known as “wolf pack” hunting style.

All of these predatory bacteria stand out not only for their unique ability to hunt down other bacteria for nutrients but also for their potential significance in biomedical research.

Researchers are actively exploring how all these predatory bacteria—and their spooky predatory behavior—can be harnessed to combat multidrug-resistant bacterial strains and to learn more about their contribution to microbiome health.