Microflora of Oral

Oral Microbiome

Totality of the oral microbes, their genetic information, and the oral environment in which they interact

Oral microbiota

All living microbes constituting the oral microbiome

Oral Bacteriome

• 3 major sub division of oral microbiome

• The total collection of bacteria and their genes within the mouth. This is the most studied and most abundant part of the oral microbiome

• The “workforce”

Oral Mycobiome

• 3 major sub division of oral microbiome

• Is the collection of fungi and yeasts in the oral cavity

• The “fungi”

Oral Virobiome

• 3 major sub division of oral microbiome

• Is the collection of all viruses in the mouth. This is often the most overlooked but arguably the most complex subdivision

• The “regulators”

Mutans Group

• Cultural characteristics: High, convex, opaque colonies; prroduce profuse extracellular polysaccharide in sucrose-containing medial; selective medium: MSA + bacitracin agar

• Main intraoral sites and infections: Tooth surfaces, dental caries

Salivarius Group

• Cultural characteristics: Large, mucoid colonies on MSA due to the production of extracellular fructans.

• Main Intraoral sites and infections: Dorsum of the tongue and saliva, streptococcus vestibularis mainly reside in the vestibular mucosa, not a major opportunistic pathogen

Planktonic Phase Organism

Suspended in Saliva

Biofilm Phase

Attached to oral surfaces, plaque

Gram Positive Cocci: Genus Streptococcus

• Predominant supragingival bacteria

• Chains, non-motile, fibrils

• Occasionally capsulated

• Facultative anaerobes

• Variable haemolysis

• Selective medium: mitis salivarius agar

Mutans Group

• Main species: Streptococcus

• Main intraoral sites and infections:

  • Tooth surface, dental caries

Salivarius Group

• Main species: Streptococcus

• Main intraoral sites and infections:

  • Dorsum of the tongue and saliva

  • S. vestibularis mainly reside in the vestibular mucosa

  • Not a mojor opportunistic pathogen

Anginosus Group

• Main species: S. constellatus, S. intermedius

• Main intraoral sites and infection:

  • Gingival crevices

  • Dentoalveolar and endodontic infections

Mitis Group

• Main species: S. sanguinis, S. gordonii, etc.

• Main intraoral sites and infections:

  • Dental plaque biofilms, tongue and cheeks, dental caries

  • Infective endocarditis

Genus Stomatococcus

• Forms large colonies adherent to blood agar surface, facultative anaerobes

• Tongue mainly, gingival crevices

• Not a major opportunisitic pathogen

Genus Granulicatella

• Previously termed “nutritionally variant streptococci”

• Non-motile, catalase and oxidase negative, non-spore forming, facultatively anaerobic requiring pyridoxal or I-cysteine for growth

• Normal oral flora

• Inhabits plaque biofilms, periodontal pockets, and root canals

• Cause serious infections (infective endocarditis)

Genus Actinomyces

• Rods & Filaments

• Ferments glucose to give characteristic patterns of short chain carboxylic acids useful for speciating, facultative anaerobes

• Earliest stages of enamel demineralization and the progression of small caries lesions

• Opportunistic pathogen causing cervicofacial

Genus Lactobacillus

• Rods & Filaments

• Catalase-negative, microaerophilic

• Common oral inhabitants

• Dental plaque biofilms

• Used to detect the cariogenic potential of the diet

Genus Eubacterium

• Rods and Filaments

• Obligatory anaerobes

• Plaque biofilms and calculus

• Implicated in caries and periodontal disease

• Comprise over 50% of the anaerobes of periodontal pockets

• “Corn-cob” formation in dental plaque

Genus Propionibacterium

• Rods & Filaments

• Strict anaerobe, morphologically indistinguisable from actinomyces but produces propionic acid from glucose

• Root surface caries, plaque biofilms

• Dentoalveolar infections

Rothia Dentocariosa

• Gram-positive branching filament, is a strict aerobe

• Found in plaque and infectiv endocarditis

Bifidobacterium dentium

• Gram-positive strict anaerobe

• Regularly isolated from plaque biofilms