Streptococci dominate the diverse flora within buccal cells

Area of Science:

• Microbiology
• Oral Biology
• Cell Biology

Background:

• Previously identified intracellular bacteria in human buccal cells included Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis.
• These bacteria were found as lesser components of a polymicrobial flora within these cells.

Purpose of the Study:

• To further characterize the intracellular flora within human buccal epithelial cells.
• To identify additional bacterial species residing within these cells using advanced techniques.

Main Methods:

• Utilized double-labeling techniques with species-specific and universal probes.
• Investigated the presence of Fusobacterium nucleatum, Prevotella intermedia, oral Campylobacter species, Eikenella corrodens, Treponema denticola, Gemella haemolysans, Granulicatella adiacens, and total streptococci.

Main Results:

• All investigated bacterial species were confirmed to be present within buccal epithelial cells.
• Species identified by specific probes were consistently accompanied by bacteria detected by a universal probe.
• Streptococci were the predominant species, found at levels 1-2 logs higher than the next most common species, Granulicatella adiacens.

Conclusions:

• Human buccal epithelial cells harbor a diverse intracellular polymicrobial flora.
• The composition of this intracellular flora, particularly the dominance of streptococci, resembles that of oral biofilms.
• This suggests complex microbial interactions and community structures exist both on surfaces and within host cells in the oral cavity.