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A Versatile Model of Hard Tick Infestation on Laboratory Rabbits
Published on: October 6, 2018
Pathogenicity of Prevotella intermedia and Prevotella nigrescens isolates in a wound chamber model in rabbits
1Department of Oral Microbiology, Faculty of Odontology, Göteborg University, Sweden.
Abstract:
The pathogenicity of 14 isolates identified as Prevotella intermedia or Prevotella nigrescens by serogrouping using monoclonal antibodies was compared in a tissue cage model in rabbits. Seven strains from periodontal abscesses, 5 strains from deep periodontal pockets and 2 strains from gingivitis were tested in the animal model comprising 6 Teflon tissue cages implanted on the back each of 34 rabbits. A total of 10(5)-10(8) cells of P. intermedia or P. nigrescens strains were inoculated alone or together with either Actinobacillus actinomycetemcomitans or Streptococcus mitis. Five strains of Porphyromonas gingivalis were used as a reference. The infectivity was recorded as pus formation and log viable count in aspirated material for 3, 7 and 14 days. None of the Prevotella strains inoculated in monoculture survived more than 3 days, and they had no capacity to produce abscess. P. intermedia or P. nigrescens strains in combination with A. actinomycetemcomitans produced abscesses in 33-100% and with S. mitis in 42-100%. No difference in abscess formation or log viable count in samples after 14 days was recorded between serogroup I (P. intermedia) and serogroup II and III (P. nigrescens). The infectivity of P. intermedia or P. nigresceas strains did not differ whether they were isolated from periodontal abscess, periodontal pocket or gingivitis. P. intermedia and P. nigrescens strains produced abscesses in combination with a facultative anaerobic strain and appears to have a similar pathogenicity in the wound chamber model in rabbits.
Insights
Prevotella intermedia and Prevotella nigrescens alone do not cause abscesses. However, these bacteria, when combined with Actinobacillus actinomycetemcomitans or Streptococcus mitis, can cause periodontal disease in rabbits.
Area of Science:
- Oral microbiology
- Periodontal disease pathogenesis
- Bacterial co-infections
Background:
- Prevotella intermedia and Prevotella nigrescens are implicated in periodontal diseases.
- Their specific pathogenic roles, especially in polymicrobial infections, require further elucidation.
Purpose of the Study:
- To compare the pathogenicity of Prevotella intermedia and Prevotella nigrescens isolates in a rabbit tissue cage model.
- To assess the role of these bacteria in polymicrobial infections with Actinobacillus actinomycetemcomitans and Streptococcus mitis.
Main Methods:
- Utilized a rabbit tissue cage model with 34 rabbits, each implanted with 6 cages.
- Inoculated 14 Prevotella isolates (from various periodontal conditions) alone or with A. actinomycetemcomitans or S. mitis.
- Recorded infectivity via pus formation and viable bacterial counts over 14 days, using Porphyromonas gingivalis as a reference.
Main Results:
- Prevotella strains alone did not survive beyond 3 days or induce abscesses.
- Co-inoculation with A. actinomycetemcomitans or S. mitis led to abscess formation in 33-100% and 42-100% of cases, respectively.
- No significant differences in pathogenicity were observed between P. intermedia and P. nigrescens, or based on their isolation source (abscess, pocket, gingivitis).
Conclusions:
- Prevotella intermedia and Prevotella nigrescens exhibit limited pathogenicity when present alone.
- These bacteria contribute to abscess formation primarily in synergistic interactions with facultative anaerobic bacteria like A. actinomycetemcomitans and S. mitis.
- The findings suggest similar pathogenic potential for P. intermedia and P. nigrescens in polymicrobial periodontal infections.
