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Oral microbiology third lecture.pdf

  1. 1. Dr.Iman  Qoraan Spring  2020 The  Resident  Oral  Microflora
  2. 2. Diversity  of  resident  flora Synergic   metabolic   interactions  by   microorganisms Dental   plaque   biofilms Diversity   of   nutrients   supplied
  3. 3. Microbial   classification   schemes Conventional Morphological   and   Physiological Chemical   properties  :   enzymes  , carbohydrate  , amino  acid,  etc... Serological  : antigen-­ antibody   reactions Molecular 16S   ribosomal   RNA  gene   amplification
  4. 4. -­Simple -­Quantitative -­Sensitivity  tests   -­Rapid(serological tests) -­Some  tests  can  be  done   directly  on  clinical  samples   (other  than  culture) -Pure  culture is  needed   -­Not  all  microorganisms  can     be  cultured(e.g:  treponema) Conventional  Identification  Methods Advantages Disadvantages
  5. 5. Around 700 microorganism present in the oral cavity Only 50% can be cultured
  6. 6. Molecular  Identification  Methods *Accurate *Rapid *Sensitive *Provide  information  about  non   culturable microorganisms *Data  sequences  is  limited *Antimicrobial  sensitivity  is  not   possible Pros Cons
  7. 7. Oral Microorganisms Bacteria Gram positive (cocci, bacilli) Gram negative (cocci, bacilli) Obligate anaerobes Mycoplasma Fungi Protozoa Archea Viruses
  8. 8. Gram  Positive    Cell  Wall  
  9. 9. A.  Mutans  streptococcus  Group Mutans(different  shapes):  cocci,  coccobacilli,bacilli Extracellular  soluble/insoluble  glucan,  mutan (insoluble   glucan),  fructan ,and  intracellular  polysaccharides   Release  signaling  molecules  that  induce  genetic  transformation   and  acid  tolerance Facultative  anaerobic  ,  acidophilic,acidogenic AntigenI/II  subunit  vaccine
  10. 10. 1. S. mutans c,e,f,k human   serotypes Favors  hard  non   shedding   surfaces   (teeth,  denture) Opportunistic (dental  caries,   endocarditis)
  11. 11. Streptococcus  mutans Gram stain Colonies on blood agar
  12. 12. 2. S.  sobrinus Inhibited  by  bacitracin d,g serotypes  are  human  specific AntigenI/II  is  also  present  (SpaA) Associated  with  dental  caries Produce  extracellular  and  intracellular   polysaccharides
  13. 13. B.  Anginosus  Group S.anginosus • Isolated from   purulent   infections    like   maxillofacial  and   other  body  sites • Don’t  produce   extracellular   polysaccharides S.intermedius • Produce   intermedilysin affect  neutrophil   function  in   abscess  formation • Don't  produce   extracellular   polysaccharides • isolated  from   brain  and liver   abscesses S.constellatus • Derived  from   purulent   infections • Don’t produce   extracellular   polysaccharides
  14. 14. Anginosus  Group S. anginosus may be B-hemolytic or none
  15. 15. • Isolated  from  vestibular  mucosa  of   mouth • Produce  urease    and  H2O2  which   inhibit  competing  bacteria • Do  not  produce  extracellular   polysaccharides • Opportunistic    endocarditis  and   bacteremia S.vestibularis • Colonize  mucosal  surfaces  mainly  the   tongue ,rarely  cause  disease • Produce  extracellular  fructan,  glucan     and  levanase • Levan  (extracllular fructan) make     mucoid  colonies  on  sucrose  containing   agar S.  salivarius C.  Salivarius  group
  16. 16. D.Mitis  group S.sanguinis Colonize   tooth   surface Produce   extracellular glucan Cleave   arginine   and   generate   ammonia Produce   IgA   prtoease S.gordonii Colonize   tooth   surface Produce   extracellular   glucan Cleave   arginine and   generate   ammonia Cleave  starch   using  salivary   alpha   amylase(binding   to  amylase   protect  it  from   host)  defenses-­ host  mimicry S.oralis produce   neuraminidase enhance   adherence  by   cleaving    sialic   acid  from  mucin   Produce  IgA   protease Competent  for   natural  genetic   transformation S.mitis Opportunistic   pathogen   misidentified  as   S.pneumoniae Cause  infective   endocarditis Competent  for   natural  genetic   transformation
  17. 17. Nutritionally  variant  streptococci ØGranulicatella adiacens(S.adiacens): ü Require  cysteine  ,pyridoxal(vitamin  B6)  for  growth ü Exhibit  satellitism with  other  bacteria  that  provide   cofactors ØAbiotrophia defectiva
  18. 18. Other  Gram  positive  cocci Ø Enterococcus  faecalis :  isolated  from  immunocompromised patients,  treatment  failed  periodontal  pocket   Ø S.pyogenes: isolated  from    saliva of  patients  with  sore  throat Ø Staphylococcus  and  Micrococci:  Transient  flora,  isolated  from   denture plaque Ø Peptostreptococcus stomatis:  anaerobic,isolated from  dental   abscesses,infected pulp  chambers,root canals  and  advanced   forms  of  periodontal  disease
  19. 19. Gram  Positive  Rods  and  Filaments
  20. 20. A.  Actinomyces A.naeslundii Major  portion  of   dental  plaque,   colonize  mouth  at   infant  age produce  fructan,   urease,neuraminidase have  fimbriae  for   coaggregation and   cell-­surface   interaction A.israelii opportunistic pathogen  cause   actinomycosis produce  protective     granules  that  help   bacteria  evade   immune  system   and  antibiotic   treatment  and   disseminate  into   body A.odontolyticus form  red   pigment colonize  mouth at  infant  age
  21. 21. B.  Eubacterium   Gram  variable,filamentous ,  obligate    anaerobe,  non culturable Asaccharolytic Form  dentoalveolar    abscesses  
  22. 22. C. Lactobacillus  species Some   species   are  cocci Acidogenic   and  acid   tolerant There    salivary   levels  are   useful  to   monitor   patient's   dietary   behavior   (carbohydrate   intake)  and   cariogenic   potential  of  a         mouth Isolated   from   advanced   caries   lesions
  23. 23. Lactobacillus  
  24. 24. Other  Gram  Positive  Rods qPropionibacterium  spp.:obligate  anaerobic,  found  in   dental  plaque qBifidobacterium  dentium:isolated  from  dental  plaque qRothia  mucilaginosa:  produce  extracellular   polysaccharides,isolated    exclusively from  the   tongue qCorynebacterium  matruchutii:  short  fat  cell  and  long   filament  growing  out(  whip-­handle  cell) Corynebacterium  matruchutii
  25. 25. Gram  Negative  Cell  Wall  and  Stain
  26. 26. Gram  Negative  Cocci Neisseria • Consume   oxygen   creating   anaerobic   environment   during  plaque   formation Moraxella  catarrhalis • opportunistic   pathogen • B-­lactamase  producer Veillonella • Strict   anaerobic • unable  to   metabolize   carbohydrates • Convert  lactic   acid  to   weaker  acid   preventing   enamel dissolution
  27. 27. Gram  Negative  Rods q Haemophilus Ø H.parainfluenzae:  Require  NAD (nicotinamide adenine  dinucleotide  ) q Aggregatibacter Ø A.actinomycetemcomitans Ø Capnophilic (require  5-­10%  CO2) Ø Opportunistic  pathogen  produce  collagenase,  IgG   protease   Ø Cause  aggressive  periodontitis  in  adults
  28. 28. Obligately    Anaerobic  Genera qBlack  pigmented  anaerobes: Ø Prevotella  and  Porphyromonas   Ø Produce  brown-­black  pigment  on  Blood  agar Ø Require  X-­factor  (hemin) Ø Isolated  from  subgingival  sites  of  dental  plaques qFusobacterium Ø Pleomorphic,long  filamentous Ø Asaccharolytic  Use  amino  acids  as  energy  source Ø Some  species  isolated  from  normal  gingival  crevice  others  are   associated  with  periodontal  disease
  29. 29. Black  pigmented  anaerobes
  30. 30. Fusobacterium
  31. 31. Obligately    Anaerobic  Genera qHelicobacter  pylori Ø Associated  with  gastritis,  peptic  ulcers  and  gastric   cancer Ø Transiently  found  in  the  mouth following  reflux  from   the  stomach  
  32. 32. Obligately    Anaerobic  Genera qSpirochaetes Ø Isolated  from  subgingival  plaque Ø Their  number  is  diagnostic  for  necrotizing  ulcerative   periodontitis Ø Characterized  by  endoplasmic  flagella(axial  filaments) Ø Difficult to  be  cultured,  need  dark  field  microscope,   molecular  methods Ø Treponema  denticola   ü Proteolytic:  degrade  collagen  and  gelatin ü Can  be  cultured
  33. 33. Spirochetes  Cell  wall  and  Gram  stain
  34. 34. Fungi Present  in   small   proportion Imperfect   yeast   (divide   asexually)   like  candida   are   common   flora Perfect (divide   sexually)   yeast  are   transient in   healthy   individuals Perfect molds  like   Aspergillus , Mucor, Geotrichum present  in   AIDS   patients
  35. 35. 1.  Candida  albicans is  the  main  oral fungal   flora 2.  C.  glabrata,  C.  krusei, C.  tropicalis, C.guilliermundii,   Rhodotorulla,   Saccharomyces     are  present 3.  Isolated  mainly  from   dorsum  of  the  tongue  and   increased with  presence  of   intra-­oral  devices  like   dentures  or  orthodontic   appliances 4.  Carriage  rate  increases   at  middle  and  old  age Fungi
  36. 36. Mycoplasma Disease  associated M.orale,  M.  salivarium associated  with  salivary  gland     hypofunction Isolation mucosal  surfaces   RT,UT Saliva M.salivarium M.pneumonaie Oral  mucosa M.buccale M.  orale Growth  media Need  enriched  media  with   protein Elevated  CO2 Shape  and  size Lack cell  wall   Gram negative  pleomorphic Smallest free  growing   cells<1um
  37. 37. Mycoplasma structure
  38. 38. Viruses 1.  Herpesviridae Herpes  simplex  virus  type1  (HSV1) • Most  virus  isolated  from  saliva   and  orofacial  areas • Persist  within  oral  tissues   • Cause  cold  sores • Remains  latent  in  trigeminal   nerve  ganglion • Reactivated by  stress  or  UV  light • Mainly  recovered  by  molecular   methods   Cytomegalovirus(CMV) • Isolated  from  saliva • Latent • persistent • Portal  entry  to  oral  cavity   is  unknown
  39. 39. Cytomegalovirus  infection
  40. 40. Viruses 2.  Coxakievirus  A Coxakievirus A serotypes   2,4,5,6,8,9,10,16 isolated  from  oral   epithelium  and  saliva Disease Herpangina(  hand,foot,mouth disease)
  41. 41. Coxakievirus
  42. 42. Viruses 3.Human  papilloma  virus(HPV) more  than  100  type 2,4,6,11,16  detected  in   oral  lesions  of  AIDS   Isolated  from  tissues   with  hyperplastic  warty   like  lesions (verruca  vulgaris)
  43. 43. Viruses Hepatits  B  &HIV HBV Present  in  saliva   of  carriers Cross  infection   threat HIV Present  in   saliva Cross  infection   threat(rare)
  44. 44. Hepatitis B HIV
  45. 45. Other  Viruses qMumps  and  measles  in  oral  lesions qBacteriophage ü Viruses  for  which  bacteria  are  the  natural  hosts ü Bacteriophage  specific  for  S.mutans,  Lactobacillus,   Actinomyces,  Veillonella and  Aggregatibacter  sp. ü Isolated  from  saliva  and  dental  plaque  samples
  46. 46. Protozoa microscopic   unicellular   eukaryotes Their  life  cycle   consist  of   trophozoite the  motile,   feeding  form)   and    cyst (protective  form) Some  are  motile  by   flagella  ,  cilia  or   pseudopodia  while   others  are  non   motile Reproduce   asexually  by   binary   fission,   (apicomplexa   reproduce   sexually
  47. 47. Protozoa Trichomonas  tenax Commensal  in  oral  cavity   Heterotrophic  (acquire   carbon  through  ingestion   of  other  microorganisms  ,   organic  matter  and   leucocytes) Motile  by  flagella  and   undulating  membrane Increase  in  patients  with   periodontal  disease Entamoeba  gingivalis First  ameobae  isolated   from  human Heterotrophic Motile  by  pseudopodia found  in  the  gingival   pocket(abnormal  depth  of   the  gingival  sulcus
  48. 48. Trichomonas tenax