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 36
age (months)
tooth emergence
molars
infectivity
window
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)
Att
acm
ent
loss
(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 Fusobact
Ampicillin 10 83 83
Amp/Sulbact 100 100 100
Cefazolin 38 83 94
Cefotaxime 62 100 100
Imipenem 100 100 100
Clindamycin 100 100 8
Erythromycin 81 94 100
Minocycline 81 100 100
Metronidazole 100 100 100
Kuriyama et al 2001
ß-lacatmase in Prevotella isolates
Species % positive
P.intermedia 17
P.melaninogenica 78
P.oralis 50
P.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