Section III BacteriologyNon-Spore-Forming Gram-Positive BacilliCorynebacterium, Propionibacterium, ListeriaActinomycetesSHIHEZIUNIVERSITY
Section III Bacteriology Non-Spore-Forming Gram-Positive Bacilli: Corynebacterium, Propionibacterium, Listeria, Actinomycetes SHIHEZI UNIVERSITY
KEY TERMS Corynebacterium+Corynebacterium diphtheriaeMetachromatic granule ListeriaActinomycetesSHIHEZI UNIVERSITY
KEY TERMS Corynebacterium Corynebacterium diphtheriae Metachromatic granule Listeria Actinomycetes SHIHEZI UNIVERSITY
Table13-1.Someofthemorecommongram-positivebailli of medicalimportanceAerobic Gram-Ppsitive Bacll With HighG+CAerobicGramPositiveBailli ithLoweContentandrregularShapeG+CContentand MoreReqular ShapeGeneraGeneraCommonCommonListeriaCorynebacteriumUncommonErysipelothrxArcanobacteriumGardnerllaRhodococcusAerotolerantanaerobes/strictanaerobesRothiaLactobailusMany other genera of skin and environmental foraClostrdium (spore-forming) (Chapter12)AerotolerantanaerobesAerobesActinomycesBails (spore-forming) (Chapter 12)PropionibacterumMajor pathogensMajor pathogen:CorynebacterumdiphtheriaeListeria monocytogenesCommon o clinicll important isolates of theEyiplothrxrhusiopthiegenus corynebacteriumCamycolatumC mintsimumCjiekeiumCpseudodiphtheriticumCstriatumCurealyticumC xerosisG+C= guanine plus ytosine base1The medially important coryneform bacteria.SHIHEZI UNIVERSITY
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CORYNEBACTERIACorynebacterium diphtheriae Rodclubed-shaped Bacterium(causes diphtheria), (SEMx240) Copyright Dr Dennis Kunkel,University of Hawai Used with permission
CORYNEBACTERIA Corynebacterium diphtheriae. Rod,clubed-shaped Bacterium (causes diphtheria), (SEM x24,000) Copyright Dr Dennis Kunkel, University of Hawaii. Used with permission
diphtheriaeCorynebacteriumGrows best under strictaerobic conditions Nonmotile, noncapsulated.club-shaped, Gram-positivebaillusMetachromatic granules atthe endsSHIHEZI UNIVERSITY
Corynebacterium diphtheriae Grows best under strict aerobic conditions Nonmotile, noncapsulated, club-shaped, Gram-positive bacillus Metachromatic granules at the ends SHIHEZI UNIVERSITY
Classification, and Antigenic Types Toxigenic strains are lysogenic for one of afamily of corynebacteriophages that carry thestructural gene for diphtheria toxin, tox Corynebacterium diphtheriae is classified into Biotypes (mitis, intermedius, and gravis according to colony morphologyLysotypes-based upon corynebacteriophage sensitivitySHIHEZI UNIVERSITY
Classification, and Antigenic Types Toxigenic strains are lysogenic for one of a family of corynebacteriophages that carry the structural gene for diphtheria toxin, tox Corynebacterium diphtheriae is classified into Biotypes (mitis, intermedius, and gravis) according to colony morphology Lysotypes based upon corynebacteriophage sensitivity SHIHEZI UNIVERSITY
Pathogenesis Colonize at the upper respiratory tract(nasopharynxToxigenic strains secrete a potent exotoxin which maycause diphtheriaDoes not produce a systemic infection Systemic toxemia may be involved A pseudomembrane forms locally+composed of fibrin, bacteria, and inflammatory cells+ which can cause chockingSHIHEZI UNIVERSITY
Pathogenesis Colonize at the upper respiratory tract (nasopharynx) Toxigenic strains secrete a potent exotoxin which may cause diphtheria Does not produce a systemic infection Systemic toxemia may be involved A pseudomembrane forms locally composed of fibrin, bacteria, and inflammatory cells which can cause chocking SHIHEZI UNIVERSITY
Clinical ManifestationsPharyngitis, fever, swelling ofthe neck oarea surrounding the skin lesionDiphtheritic lesions are covered by apseudomembraneThe toxin is distributed to distant organsby the circulatory system and may causeparalysis and congestive heart failureSHIHEZI UNIVERSITY
Clinical Manifestations Pharyngitis, fever, swelling of the neck or area surrounding the skin lesion Diphtheritic lesions are covered by a pseudomembrane The toxin is distributed to distant organs by the circulatory system and may cause paralysis and congestive heart failure SHIHEZI UNIVERSITY
This child has diphtheria resulting in a thickgray coating over back of throat. Thiscoating can eventually expand down throughairway and, if not treated, the child could diefrom suffocation
This child has diphtheria resulting in a thick gray coating over back of throat. This coating can eventually expand down through airway and, if not treated, the child could die from suffocation
Pathogenesis of Diphtheria3.DiseaseEntryPhayngeal diphthenia4. ExitPharyngitisHypoxia-pseudomermbraneobstructionFever2.Spread -bactenaLympradenitisrarely becomeCutaneous diphtheriadisseminated butSystemic complicationstaxin becomesToxicperipheralneuropathyblood bormneToxic myocarditis andcongestiveheart failureSHIHEZI UNIVERSITY
Pathogenesis of Diphtheria SHIHEZI UNIVERSITY