Bacteriophage therapy, specifically using the FNU1 virus, may show promise as an alternative to antibiotics for treating periodontal disease by selectively attacking Fusobacterium polymorphum, a key bacteria that enables gum disease development.
- FNU1 bacteriophage selectively targets Fusobacterium polymorphum, a keystone bacterium that supports gum disease development.
- In dual-species biofilms, FNU1 reduced bacterial cell density by 83.4%, and in four-species biofilms by 94.2%.
- Phage therapy may offer a precise, targeted approach that preserves healthy bacteria while eliminating disease-causing pathogens.
- This treatment potentially addresses growing concerns about antibiotic resistance in periodontal disease management.
Using a bacteriophage, a virus that infects bacteria and replicates inside them, may dismantle bacteria behind periodontal disease, offering a potential alternative to antibiotics. The study recently was published in the Journal of Oral Microbiology.
The FNU1 virus appears to selectively attack Fusobacterium polymorphum, a species of bacteria linked to gum disease that supports and enables other bacteria to thrive, according to a study believed to be the first of its kind.
"By targeting one of the key bacteria that holds these disease-causing communities together, we were able to destabilise the entire plaque community,” said the study’s lead author, Mwila Kabwe, PhD, MSc, a postdoctoral research fellow at La Trobe's Holsworth Biomedical Research Centre (J Oral Microbiol, September 6, 2026, Vol. 18:1, 2726627). “The findings suggest phages could offer a more precise way to treat gum disease while preserving healthy bacteria.”
A new tool in the fight against gum disease?
Bacteriophages may offer a promising alternative to antibiotic therapy to fight periodontal disease, especially given concerns about antibiotic resistance.
Bacteriophages destroy bacterial communities in a way similar to the hijacking strategy viruses use to infect cells. A bacteriophage injects its DNA into a bacterium’s cell wall. The phage DNA extinguishes the bacterium's gene expression, redirecting its ribosomes to read phage genes instead. Simultaneously, the phage uses the bacterium's nucleotide pool and energy to replicate copies of its own genome. These newly made proteins and DNA copies then self-assemble into complete phage particles inside the cell. Once enough new phages have formed, phage-produced enzymes break down the bacterial cell wall and release the new phages to infect nearby bacteria.
To explore the use of bacteriophages against gum disease, the researchers used an in vivo design.
Using FNU1 to attack multiple biofilms
In the study, Kabwe and the research team established multiple in vitro biofilms using the following:
- F. polymorphum, Tannerella forsythia, and Prevotella intermedia
- T. forsythia and P. intermedia in dual-species biofilms with F. polymorphum
- Complex biofilms involving F. polymorphum, T. forsythia, P. intermedia, and Porphyromonas gingivalis
The biofilms were then exposed to FNU1, with the results measured using confocal laser scanning microscopy and live dead staining.
In the F. polymorphum and P. intermedia biofilm, FNU1 reduced cell density by approximately 83.4% (173,131/207,640 cells/mm). The total biofilm disruption capacity of FNU1 on F. polymorphum and T. forsythia was 76.3% (45,424/59,552 cells/mm2), the researchers wrote.
For the four-species biofilm, FNU1 reduced total cell density (which researchers estimated by proliferative tracking) by 94.2% (1,326,955/1,408,005 cells/mm). Total F. polymorphum, P. gingivalis, P. intermedia, and T. forsythia cells were reduced by 97.5% (798,901 cells/mm2), 85.3% (196,144/229,914 cells/mm2), 93.2% (208,185/223,282) and 91.6% (123,725/135,060), respectively, the team wrote.
“This finding is novel and unique, as it illustrates that targeting a single keystone bacterium, F. polymorphum, using bacteriophages can lead to the collapse of complex pathogenic biofilms,” Kabwe and colleagues wrote.
