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ACTA
STOMATOLOGICA
NAISSI

 Table of Contents for
March 2003 • Volume 19 • Number 41

NORMAL ORAL FLORA -  A NEW CLASSIFICATION-    PART I

 

Kesić Lj. 1, Jovanović G.2
Burić N.2, Kojović D.1
Branković V.1, Živković R.1

1Medical faculty, Department of Oral medicine and periodontology
2Medical faculty, Department of Oral surgery, Niš, Serbia


            NORMAL ORAL FLORA 

Oral flora is consisted of a diverse group of microorganisms and it is included bacteria, funi, mycoplasmas, protozoa, and possibly a viral flora which may persist from time to time. Bacteria are the predominant group of microorganisms. There are  probably 350 different cultivable species and a further proportion of unculturable flora, which are identified using molecular techniques.This, and the fact that oral cavity has a wide range of sites with different enviromental conditions,  makes the studing  of    microbiology very complex and difficult. Interesting fact is that many organisms commonly isolated from neighbouring ecosystems such as the skin are not found in the mouth. So, this indicating the unique and selective properties of the oral cavity with regard to mictobial colonisation.2,3

Oral bacteria can be classified primarly on Gram positive and Gram negative microorganisms, and secondarly as either anaerobic or facultatively anaerobic according to their oxygen requirements.

FLORA OF THE ORAL CAVITY

Gram-  positive cocci

Genus Streptococcus

 mutans group

  • Main species:  Streptococcus mutans serotypes  c,e,f;
                           Streptococcus sobrinus serotypes  d, g
                           Streptococcus cricetus  serotype  a
                           Streptococcus rattus serotype  b
                           Streptococcus ferus
                           Streptococcus macacae
                           Streptococcus downei serotype  h.
  • Main intraoral sites and infections: tooth surface, dental caries.1,3

salivarius group

  • Main    species: Streptococcus salivarius
                            Streptococcus vestibularis.
  • Main intraoral sites and infections:dorsum of tongue and saliva;  S.vestibularis mainly reside in the vestibular mucosa (hence the name); not a major oral pathogen.1,3

anginosus group

  • Main species: Streptococcus constellatus
                         Streptococcus intermedius
                         Streptococcus anginosus.
  • Main intraoral sites and infections: gingival crevice; dentoalveolar and endodontic infections.1,3

 mitis group

  • Main species:     Streptococcus mitis
                              Streptococcus sanguis
                              Streptococcus sanguis
                              Streptococcus gordonii
                              Streptococcus oralis
                              Streptococcus crista.
  • Main intraoral sites and infections: mainly dental plaque; tongue and cheek, dental caries (?), infective andocarditis (except S.mitis).1.3

 

ANAEROBIC   STREPTOCOCCI  

Genus Peptostreptococcus

·     Main species: Peptostreptococcus anaerobius
                        Peptostreptococcus micros
                        Peptostreptococcus magnus

·     Main intraoral sites and infections: teeth, especially carious dentine, periodontal and dentoalveolar abscesses in mixed culture.1,3

 Genus Staphylococcus

·     Main species: Staphylococcus aureus
                        Staphylococcus epidermidis
                        Staphylococcus saprophyticus                      

·     Main intraoral sites and infections: Staphylococci cause a variety of both common and uncommon infections, such as abscesses of many organs, endocarditis, gastroenteritis and toxic shock syndrome. Higher proportions of S.aureus are found in the saliva of healthy subjects older than  70 years.1,2,3    

Genus Stomatococcus

·     Main species: Stomatococcus (previous Micrococcus) mucilagenosus. 

·     Main intraoral sites and infections: tongue mainly, gingival crevice, not a major opportunist pathogen.1,3 

 

GRAM - POSITIVE  RODS AND FILAMENTS 

Genus Actinomyces

·        Main species: Actinomyces israelli
                        Actinomyces gerencseriae
                        Actinomyces odontolyticus
                        Actinomyces naeslundii (genospecies 1 i 2)
                        Actinomyces myeri
                        Actinomyces georgiae.                                   

The most important human pathogen is A.israelli

·     Main intraoral sites and infections: Actinomyces odontolyticus, earliest stages in enamel demineralization, Actinomyces naeslundii implicated in root surface caries and gingivits; Actinomyces israelii  is an  opportunist pathogen causing cervicofacijal and ileocaecal  actynomycosis; Actinomyces gerencseriae i actinomyces georgiae  are  minor  components of healthy  gingival flora.1,3 

Genus Lactobacillus

·        Main  species:     Lactobacillus casei
                             Lactobacillus fermentum
                             Lactobacillus acidophilus (thers includes)
                             Lactobacillus salivarius and  Lactobacillus rhamnosus).                                           

·        Main intraoral sites and infections: Dental  plaque, they are used for detecting the  cariogenic  potential of the  diet.3,4

Genus Eubacterium

·        Main species: Eubacterium brachy
                        Eubacterium timidum
                        Eubacterium nodatum
                        Eubacterium saphenum.                                        

  • Main intraoral sites and infections:Dental plaque and calculus, implicated in  caries and  perodontal disease.3,4

Genus Propionibacterium

  • Main species: Propionibacterium acnes (includes Propionibacterium acnes, formerly Arachnia propionica).
  • Main intraoral sites and infections: root surface caries, dental plaque.  Possible involvement in dentoalveolar infections.3 

Other notable Gram- positive  organisms:

  • Rothia dentocariosa, strict aerobe, found in dental plaque.
  • Bifidobacterium dentium je Gram -  positive  strict anaerobe  regularly  isolated from  dental plaque4; its role in disease is unclear.3,4

 Literature

  1. Bagg J, MacFarlane TW, Poxton IR, Miller CH, Smith AJ.:Essentials of microbiology for Dental students, Oxford University press, 2002.
  2. Listgarten  MA.: The structure of dental plaque. Periodontology 2000;5:52-65.
  3. Marsh  PD, Martin  MV.: Oral microbiology (4th edition) Butterworth - Heineman, London ,1999.
  4. Samaranayake LP.: Essential Microbiology for Dentistry (second edition). Churchill & Livingstone, 2002.
     
...Authors and Reprint Information

Ass. Prof. dr Ljiljana Kesić
Clinic of Dentistry Faculty of Medicine,
University of Niš
52 Braće Tasković street
Niš, Serbia
e-mail: kesic@bankerinter.net
  • Copyright © 2003 by The Editorial Council of The Acta Stomatologica Naissi