A new study from the University at Buffalo reports that the bacterium Veillonella parvula supports the development of gum disease by promoting multiplication of the pathogen Porphyromonas gingivalis.
Published in The ISME Journal, the study set out to clarify how P. gingivalis establishes colonies in the mouth.
Researchers asked how this pathogen could expand when growth factors appeared scarce. They discovered that P. gingivalis obtains critical growth molecules from V. parvula, a common member of the oral microbiome.
The presence of V. parvula by itself is not harmful. When V. parvula proliferates—typically in mouths with poor hygiene—it can trigger replication and expansion of P. gingivalis.
Highlights of the study
Investigators at the UB School of Dental Medicine have examined P. gingivalis for nearly two decades. Key findings from the current work include:
- The team used a relevant mouse model and in vitro culture systems to study how specific growth molecules influence P. gingivalis growth and colonization.
- They selected five bacterial species commonly associated with gum disease and tested how each species’ growth molecules affected P. gingivalis.
- Of the five, only growth molecules from V. parvula stimulated P. gingivalis multiplication.
- When V. parvula was removed from the microbiome, P. gingivalis stopped expanding. Presence of V. parvula alone was not sufficient—P. gingivalis replication required V. parvula to be abundant.
- The relationship appears unidirectional: sharing growth molecules benefits P. gingivalis but provides no clear advantage to V. parvula.
- V. parvula also produces heme, a blood-derived compound that supplies iron and serves as another resource for P. gingivalis.
- The unidirectional interaction was supported by increased periodontal bone loss caused by P. gingivalis when V. parvula was present in large numbers.
- It remains unclear whether P. gingivalis produces growth-stimulating molecules similar to those from V. parvula; further research is needed.
Why this matters
Gum disease is common: the CDC reports that over 47% of adults aged 30 and older have some form of periodontal disease. Understanding how oral microbes interact can inform better prevention and treatment strategies.
The study suggests several implications for clinical management and oral health:
- In healthy mouths, P. gingivalis typically constitutes a tiny fraction of the microbial community and cannot effectively multiply.
- With poor oral hygiene and inadequate plaque control, V. parvula can proliferate and produce sufficient growth molecules to trigger P. gingivalis replication, enabling the pathogen to expand and contribute to disease.
Targeted therapies that reduce V. parvula abundance or block the specific growth molecules it produces could help limit P. gingivalis expansion and reduce disease severity. However, V. parvula is not inherently harmful; its role becomes problematic when it overgrows. Therefore, maintaining good oral hygiene and effective plaque control remain essential strategies for preventing and managing periodontal disease.
References
- Anilei Hoare, Hui Wang, Archana Meethil, Loreto Abusleme, Bo-Young Hong, Niki M. Moutsopoulos, Philip D. Marsh, George Hajishengallis & Patricia I. Diaz (2020). The ISME Journal. “A cross-species interaction with a symbiotic commensal enables cell-density-dependent growth and in vivo virulence of an oral pathogen.”