Experimentally induced infection by oral anaerobic microorganisms in a mouse model

Area of Science:

• Microbiology
• Oral Biology
• Infectious Diseases

Background:

• Endodontic infections often involve complex polymicrobial communities of oral anaerobes.
• Understanding the abscessogenic potential of these bacteria is crucial for effective treatment strategies.

Purpose of the Study:

• To develop and utilize a mouse model for evaluating the abscess-forming capabilities of pure and mixed oral anaerobes.
• To identify specific bacterial species and combinations that contribute significantly to abscess development in endodontic infections.

Main Methods:

• Development of a subcutaneous mouse model for inducing and observing abscess formation.
• Inoculation with pure and mixed cultures of oral anaerobes, including Fusobacterium nucleatum, Peptostreptococcus anaerobius, Veillonella parvula, Porphyromonas gingivalis, and Prevotella intermedia.
• Histopathological examination of tissue sections and assessment of lesion development over time.

Main Results:

• Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Veillonella parvula demonstrated pathogenicity in pure cultures.
• Mixed cultures of F. nucleatum with Porphyromonas gingivalis or Prevotella intermedia exhibited significantly enhanced pathogenicity compared to F. nucleatum alone.
• Histological analysis revealed a pathway for particulate migration from inoculation sites to the abdomen in control mice.

Conclusions:

• The developed mouse model effectively simulates abscess formation by oral anaerobes relevant to endodontic infections.
• Specific combinations of oral anaerobes, notably F. nucleatum with P. gingivalis or P. intermedia, possess synergistic virulence contributing to increased abscessogenicity.
• Findings highlight the importance of polymicrobial interactions in the pathogenesis of endodontic abscesses.