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Published on: August 8, 2014
Synergistic pathogenicity of Porphyromonas gingivalis and Fusobacterium nucleatum in the mouse subcutaneous chamber
Zvi Metzger1, Yuh-Yih Lin, Fernando Dimeo
1Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill, North Carolina, USA.
Abstract:
Porphyromonas gingivalis and Fusobacterium nucleatum are often coisolated from sites of infection, such as suppurative apical periodontitis. The synergistic pathogenicity of mixed infection of P. gingivalis HG 405 with F. nucleatum PK 1594 was studied in the mouse subcutaneous chamber model in groups of seven animals. The minimal dose for P. gingivalis HG 405 that was required to infect 100% of the chambers was reduced by 1,000-fold when animals were inoculated in the same chamber with 1 x 10(9)F. nucleatum PK 1594 (p < 0.001). To benefit from the presence of the fusobacteria, P. gingivalis HG 405 had to be coinoculated; inoculation in separate chambers for the same animal had no such effect (p < 0.001). Subinfective F. nucleatum inocula also benefited from the association with P. gingivalis HG 405 and uniformly established an infection when this partner was present (p < 0.001). These results suggest that the frequent and natural coexistence of P. gingivalis and F. nucleatum in diseased sites may express such a synergism in successful establishment and survival of small inocula.
Insights
Porphyromonas gingivalis and Fusobacterium nucleatum exhibit synergistic pathogenicity. Co-infection significantly reduces the infectious dose for P. gingivalis, enhancing bacterial survival in mixed infections.
Area of Science:
- Oral microbiology
- Infectious diseases
- Bacterial pathogenesis
Background:
- Porphyromonas gingivalis and Fusobacterium nucleatum are frequently found together in infections.
- Suppurative apical periodontitis is one such infection where these bacteria are coisolated.
Purpose of the Study:
- To investigate the synergistic pathogenicity of P. gingivalis and F. nucleatum in a mixed infection model.
- To determine the effect of co-inoculation on the infectious dose and survival of these bacteria.
Main Methods:
- Utilized a mouse subcutaneous chamber model with groups of seven animals.
- Assessed the minimal infectious dose of P. gingivalis HG 405 when co-inoculated with F. nucleatum PK 1594.
- Compared co-inoculation in the same chamber versus separate chambers.
Main Results:
- Co-inoculation with F. nucleatum reduced the minimal infectious dose of P. gingivalis by 1,000-fold.
- P. gingivalis required co-inoculation in the same chamber to benefit from F. nucleatum.
- Subinfective doses of F. nucleatum uniformly established infection in the presence of P. gingivalis.
Conclusions:
- A significant synergistic pathogenicity exists between P. gingivalis and F. nucleatum.
- Their frequent co-occurrence in diseased sites may be due to this synergism, aiding the establishment and survival of small bacterial inocula.
