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Updated: Aug 27, 2025
Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells
Published on: December 17, 2015
Enterococcus faecalis Shields Porphyromonas gingivalis in Dual-Species Biofilm in Oxic Condition
Huan Chang Tan1, Gary Shun Pan Cheung1, Jeffrey Wen Wei Chang1
1Division of Restorative Dental Sciences, Faculty of Dentistry, University of Hong Kong, Pokfulam, Hong Kong SAR, China.
Abstract:
Aim: To develop a reproducible biofilm model consisting of Enterococcus faecalis (E. faecalis) and Porphyromonas gingivalis (P. gingivalis) and to evaluate the interaction between the two bacterial species. Methodology: E. faecalis and P. gingivalis were grown in mono-culture, sequential, and co-culture models for 96 h in a 96-well polystyrene microtiter plate under both aerobic and anaerobic conditions separately. The viability of the two bacterial species in the biofilms was quantified by polymerase chain reaction (qPCR). Biofilm thickness and protein contents were measured using confocal laser scanning microscopy (CLSM). Two-way analysis of variance (ANOVA) was performed to analyze cell viability and biofilm thickness among different culture models cultivated under either aerobic or anaerobic conditions. The level of significance was set at p < 0.05. Results: Different culture models tested did not show any significant difference between the viable cell counts of both E. faecalis and P. gingivalis cultivated under aerobic and anaerobic conditions (p > 0.05). Biofilm was significantly thicker (p < 0.05) in the co-culture models compared to the mono-culture and sequential models. Protein contents in the biofilms were more pronounced when both bacterial species were co-cultured under aerobic conditions. Conclusions: E. faecalis appeared to shield P. gingivalis and support its continued growth in oxic (aerobic) conditions. The co-culture model of E. faecalis and P. gingivalis produced a significantly thicker biofilm irrespective of the presence or absence of oxygen, while increased protein contents were only observed in the presence of oxygen.
Insights
This study developed a reproducible biofilm model using Enterococcus faecalis and Porphyromonas gingivalis. Co-culturing these bacteria significantly increased biofilm thickness, with higher protein content under aerobic conditions.
Area of Science:
- Microbiology
- Oral Health Research
- Bacterial Interactions
Background:
- Enterococcus faecalis and Porphyromonas gingivalis are key bacteria in oral biofilm formation.
- Understanding polymicrobial interactions is crucial for developing effective therapeutic strategies.
Purpose of the Study:
- To establish a reproducible in vitro biofilm model using Enterococcus faecalis and Porphyromonas gingivalis.
- To investigate the synergistic and antagonistic interactions between these two species under varying oxygen conditions.
Main Methods:
- Mono-culture, sequential, and co-culture biofilm models were established in 96-well plates over 96 hours.
- Bacterial viability was assessed using quantitative polymerase chain reaction (qPCR).
- Biofilm thickness and protein content were measured using confocal laser scanning microscopy (CLSM) and analyzed with two-way ANOVA.
Main Results:
- No significant difference in viable cell counts for either species was observed between aerobic and anaerobic conditions across different culture models.
- Co-culture models resulted in significantly thicker biofilms compared to mono-culture and sequential models (p < 0.05).
- Increased protein content was observed in co-cultures under aerobic conditions.
Conclusions:
- Enterococcus faecalis may provide a protective effect for Porphyromonas gingivalis, facilitating its survival in aerobic environments.
- The co-culture of E. faecalis and P. gingivalis consistently yields thicker biofilms, regardless of oxygen availability.
- Enhanced protein production in biofilms is specific to co-culturing under aerobic conditions.
