Bdellovibrio-and-Like Organisms (BALOs) are bacteria that have a unique lifestyle; they are predatory bacteria that attack and kill other bacterial species. The majority of the BALOs do this by squeezing inside the prey bacteria and using enzymes to dissolve the contents of the prey cell for use as food. Once they have eaten their fill, the BALOs multiply and then pop out of the digested prey cell to continue their lifecycle on further prey. BALOs do not predate all bacterial cells, but only those with a double membrane – ‘Gram negative’ species.
There are several bacterial species that are known to play a role in the pathogenesis of colorectal cancer (CRC). These are certain forms of E. coli, Bacteroides fragilis, and Fusobacterium nucleatum, collectively known as ‘oncomicrobes’. All of these species are Gram negative, and thus potentially vulnerable to attack by BALOs. Instead of treating a patient with broad-spectrum antibiotics, which risks promoting antibiotic resistance and damaging the microbial environment of the colon, could predatory bacteria be put to work to remove undesirable, cancer-promoting microbes from the colon?
The current goal of my research is thus to isolate BALOs from the environment and to then test them for their predation efficacy against oncomicrobes such as F. nucleatum. Those that are shown to be efficient predators will be further ‘trained’ to improve their predatory behavior within conditions such as those found within the human gut. The hope is to find BALO strains which are effective predators against CRC-promoting oncomicrobes, and could be used therapeutically to reduce or remove such oncomicrobes from the colon without damaging the rest of the microbiota or the colon itself.