Acute pseudo-membranous

candidosis

Acute erythemat

ous candidosis

Actinomycosis

Herpes simplex

Oral Infections

Dr Ian DouglasUniversity of Sheffield

Acquisition of oral flora• At birth oral cavity is sterile• Most species acquired during

the first 2 years of life• Flora mainly acquired from

mother– its all in a kiss!

Acquisition of mutans streptococci

6 12 18 24 30 36age (months)

tooth emergencemolars

infectivitywindow

Plaque -in vivo biofilm

Dental caries

Stephan Curve

3

4

5

6

7

0 1 2 3 4 5 6 7 8 9 10 11 12 13

NormalSnacking

Hours

pulses

pH in plaque

Prevalence of some bacteria in caries

% viable count

Progressive Non-progressive

mutans 10 3

S.sanguis 6 9

S.oralis 4 5

Lactobacillus 1 0

Veillonella 11 9

Actinomyces 29 33

Mechanical removal of plaque?

Toothbrushbristle

Topical passive immunisation

•Anti S.mutans s-IgA cloned into tobacco

•3 week application eliminated oral S.mutans

Replacement Therapy -Superbugs

S

•Potent bacteriocin producer

•Stable LDH-deficient mutant

• Produces ethanol & other acids

•Imported adh gene

bacteriocin

bacteriocin

bacteriocin

Destructive Periodontitis

Disease Progression

0123456789

10

20 35 45 55

Age (years)

Atta

cmen

t los

s (m

m)

A.odontolyticusV.parvula

Association of organisms with disease

Pr.intermediaAt.actinomycetemcomitans

Pr.nigrescensF.nucleatum

Pt.microsC.rectus

P.gingivalisTa.forsythusT.denticola

S.mitisS.oralis

S.sanguis

Health Disease

Periodontal species detected by 16srRNA

DeferribacteresSpirochaetesFusobacterium animalisAtopobium parvulumAtopobium rimaeEubacterium sp.Megasphaera sp.Abiotrophia adiacensCatonella morbiDialister pneumonsintesEubacterium saphenumFilifactor alocisGemella haemolysansSelenomonas sp.Streptococcus constellatusDesulfobulbus sp. R004Campylobacter gracilisCampylobacter rectusHaemophilus parainfluenzaeBacteroides forsythusPrevotella tanneraePorphyromonas endodontalisPorphyromonas gingivalis

• Estimate 415 species•~40% were novel phylotypes•Detected in at least four diseased subjects, but not in healthy subjects

Paster B J Bact 2001; 183; 3770-3783

Periapical disease

Bacteria associated with endodontic treatment

failureSpecies No.casesE.faecalis 9S.anginosus 2S.constellatus 1S.intermedius 1Pept.micros 2A.israelii 3Prop.acnes 1F.nucleatum 1B.gracilis 3

Spread of infection from the tooth

Examples of oral abscesses

Bacterial genera in periapical abscesses

Anaerobes FacultativesGram-negative Gram-negativePrevotella* EikenellaPorphyromonas* CapnocytophagaFusobacterium* HaemophilusCampylobacter*VeillonellaBacteroidesTreponema

Gram-positiveGram-positive Streptococcus*Peptostreptococcus* EnterococcusEubacterium* LactobacillusPropionibacterium Actinomyces

* most frequently recovered

Antibiotic sensitivity among oral anaerobes

Prevotella Porphyro FusobactAmpicillin 10 83 83Amp/Sulbact 100 100 100Cefazolin 38 83 94Cefotaxime 62 100 100Imipenem 100 100 100Clindamycin 100 100 8Erythromycin 81 94 100Minocycline 81 100 100Metronidazole 100 100 100

Kuriyama et al 2001

ß-lacatmase in Prevotella isolates

Species % positiveP.intermedia 17P.melaninogenica 78P.oralis 50P.buccae 25

Summary• Oral infections are polymicrobial• Generally caused by endogenous

commensal species• There is relatively little microbial

specificity for the different types of lesion (except dental caries?)

• Some oral infections pose treatment problems due to antimicrobial resistance