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04/18/23
Streptococcus
Hugh B. FackrellHugh B. Fackrell
Filename:Filename:Strept.pptStrept.ppt
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Streptococcus Outline
StreptococcusStreptococcus Characteristics Characteristics Streptococcal DiseasesStreptococcal Diseases
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Streptococcus: characteristicsStreptococcus: characteristics
Genus definitionGenus definition Growth requirementsGrowth requirements CapsuleCapsule Colonial morphologyColonial morphology HemolysisHemolysis
Destruction of RBCsDestruction of RBCs Hemolysins Hemolysins
molecules that destroy RBCsmolecules that destroy RBCs
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StreptococcusGenus Definition
Gram +ve cocci, chains or pairsGram +ve cocci, chains or pairs Catalase -ve facultative Catalase -ve facultative
anaerobesanaerobes some strictly anaerobicsome strictly anaerobic some capnophilic (COsome capnophilic (CO22))
Ferment sugars to mixed acids Ferment sugars to mixed acids and ethanoland ethanol
Lancefield group D is motileLancefield group D is motile
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FastidiousFastidious
Most Streptococci are Most Streptococci are fastidious in their fastidious in their growth requirementsgrowth requirements
Grow poorly on Grow poorly on nutrient agarnutrient agar
Grow well on blood Grow well on blood agaragar
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Capsule
Made of hyaluronic acid: Made of hyaluronic acid: polymer of glucuronic acid & N-polymer of glucuronic acid & N-
acetylglucosamineacetylglucosamine Non immunogenicNon immunogenic
hyaluronic acid intercellular cementhyaluronic acid intercellular cement detected only in young(2-4 h) detected only in young(2-4 h)
broth culturesbroth cultures bacteria producebacteria produce hyaluronidasehyaluronidase
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Colonial Morphology
GLOSSY:GLOSSY: no capsule, no capsule, colonies smallcolonies small
MUCOID:MUCOID: capsule, capsule, colonies are large, colonies are large, glistening, viscousglistening, viscous
MATT:MATT:capsule, older capsule, older colonies are dried, colonies are dried, flatter rougher flatter rougher
Glossy
Mucoid
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Two Forms of HemolysisTwo Forms of Hemolysis
Beta HemolysisClearing
Alpha Hemolysis Greening “viridans”
(Gamma hemolysis = no lysis)
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Streptococcal Beta HemolysisStreptococcal Beta Hemolysis
Two hemolysinsTwo hemolysins Both cause clearingBoth cause clearing Both involved in diseaseBoth involved in disease
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Hemolysin S (stable in air)Hemolysin S (stable in air)
Beta hemolysis on blood agarBeta hemolysis on blood agar Do not develop antibodiesDo not develop antibodies Induces arthritisInduces arthritis Two partsTwo parts
CarrierCarrier hemolysin polypeptidehemolysin polypeptide
cell bound hemolysincell bound hemolysin lyses leukocytes and plateletslyses leukocytes and platelets stimulates release of lysosomal contentsstimulates release of lysosomal contents
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Hemolysin OHemolysin O
OxidizedOxidized in air in air oxygen labile (reversible)oxygen labile (reversible) ProteinProtein CardiotoxicCardiotoxic patients develop antibodiespatients develop antibodies ASOTASOT cholesterol labile (irreversible)cholesterol labile (irreversible)
Antistreptolysin O testAntistreptolysin O test
Subsurface colony of Streptococcus
producing Hemolysin 0
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Streptococcus pyogenes Suppurative DiseasesStreptococcus pyogenes Suppurative Diseases
PharyngitisPharyngitis Scarlet FeverScarlet Fever Erysipalas ( St. Antony’s Erysipalas ( St. Antony’s
fire)fire) CellulitisCellulitis Puerperal FeverPuerperal Fever SepsisSepsis MeningitisMeningitis PneumoniaPneumonia
Subacute Bacterial Subacute Bacterial EndocardititisEndocardititis
Otitis MediaOtitis Media
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Diseases of S. pyogenesDiseases of S. pyogenes
Pharyngitis:Pharyngitis: incubation period of 2 to incubation period of 2 to
4 days4 days sore throat, fever, sore throat, fever,
malaise, headachemalaise, headache Erythema of the pharynxErythema of the pharynx cervical cervical
lymphadenopathylymphadenopathy diagnosis -- differential diagnosis -- differential
-- viral pharyngitis-- viral pharyngitis
Scarlet fever:Scarlet fever: all of the above plus all of the above plus
red rash and red tonguered rash and red tongue
PyodermaPyoderma Non-suppurative, Non-suppurative,
inflammatory:inflammatory:
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Streptococcal SuppurationStreptococcal Suppuration
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Puerperal FeverPuerperal Fever
““Childbirth Fever”Childbirth Fever” SemmelweisSemmelweis
Membranes of genital Membranes of genital tract rupturedtract ruptured fulminating septicemiafulminating septicemia fatal 24-48 hrfatal 24-48 hr
S. pyogenesS. pyogenes 60-75% of 60-75% of casescases Anaerobic streptococci Anaerobic streptococci
20-25%20-25%
S. pyogenesS. pyogenes Not Not isolated from vagina isolated from vagina of healthy females of healthy females before birthbefore birth 50-60% from physician50-60% from physician rest from own nose & rest from own nose &
throatthroat
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Post vaccination Streptococcal InfectionPost vaccination Streptococcal Infection
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Streptococcal CellulitisStreptococcal Cellulitis
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Scarlet FeverScarlet Fever
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Scarlet Fever RashScarlet Fever Rash
Peticial Peticial hemorrhagehemorrhage Pin pointPin point SubcutaneousSubcutaneous
Erythrogenic toxinErythrogenic toxin Scarletina toxinScarletina toxin causes rashcauses rash associated with a associated with a
temperate phagetemperate phage
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Scarlet FeverScarlet Fever
Strawberry Tongue
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Schultz-Charlton testSchultz-Charlton test
Inject 0.1 ml antitoxin subcutaneouslyInject 0.1 ml antitoxin subcutaneously Rash fades after 6-8 hours (possible delay Rash fades after 6-8 hours (possible delay
14 h) 14 h) Differentiates from other similar rashesDifferentiates from other similar rashes
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Erysipalas Erysipalas
Secondary invasionSecondary invasion minor original lesion minor original lesion
Skin reddened thickenedSkin reddened thickened later purple later purple
Bacteria only in advancing Bacteria only in advancing edgeedge
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Erysipalas: butterfly rashErysipalas: butterfly rash
Butterfly rashButterfly rash common near nosecommon near nose spreads after 4-6 daysspreads after 4-6 days
Septicemia common Septicemia common complicationcomplication
No toxinNo toxin No immunityNo immunity
repeated attacks possiblerepeated attacks possible
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Rheumatic FeverRheumatic Fever
autoimmuneautoimmune acute glomerulonephritisacute glomerulonephritis Acute, non suppurativeAcute, non suppurative post streptococcal inflammationpost streptococcal inflammation
Joints, heart valves,myocardium,nervesJoints, heart valves,myocardium,nerves choreachorea- inflammation of nerves- inflammation of nerves
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Scarred heart valvesScarred heart valves
reduced cardiac outputreduced cardiac output heart failureheart failureMitral valve stenosis Mitral valve stenosis edema, hypertension, hematuria and edema, hypertension, hematuria and
proteinuriaproteinuria
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Scarred heart valvesScarred heart valves
Rheumatic EndocarditisRheumatic Endocarditis
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Rheumatic fever latent periodRheumatic fever latent period
Latent period 2-4 weeksLatent period 2-4 weeks same after repeated infectionssame after repeated infections
not immunologicalnot immunological Antibiotics taken during first week of Antibiotics taken during first week of
pharyngeal infectionpharyngeal infection Drop Steptococcal countDrop Steptococcal count Block rheumatic feverBlock rheumatic fever
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Aschoff BodiesAschoff Bodies
Inflammation of myocardiumInflammation of myocardium Mononuclear cell infiltrationMononuclear cell infiltration Granuloma-like nodulesGranuloma-like nodules Characteristc of rheumatic feverCharacteristc of rheumatic fever
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Streptococcal Antigens
Lancefield groupsLancefield groups M antigensM antigens T antigensT antigens R antigensR antigens
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StreptococcusLancefield GroupsStreptococcusLancefield Groups
Rebecca LancefieldRebecca Lancefield Grouped by presence of distinctive cell wall Grouped by presence of distinctive cell wall
antigensantigens Polysacchardies or glycero teichoic acidsPolysacchardies or glycero teichoic acids
Antigens labelled A-TAntigens labelled A-T exclude I & J exclude I & J
Group A Streptococci Clinically ImportantGroup A Streptococci Clinically Important
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Lancfield GroupsLancfield Groups
S. pneumoniae N/AS. pneumoniae N/A S.pyogenes -- Lancefield Group AS.pyogenes -- Lancefield Group A S.agalactiae -- Lancefield Group BS.agalactiae -- Lancefield Group B Enterococcus-Lancefield Group DEnterococcus-Lancefield Group D Viridans groupViridans group
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Group A StreptococciGroup A Streptococci
S. pyogenesS. pyogenes Group A Group A clinically importantclinically important
Lancefield grouping time Lancefield grouping time consumingconsuming
Group A correlated with Group A correlated with sensitivity to bacitracinsensitivity to bacitracin
Bacitracin sensitive Beta hemolytic Strept reported as Group A Strept
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Group D StreptococciGroup D Streptococci
glycerol teichoic acid glycerol teichoic acid -- associated with the -- associated with the cytoplasmic cytoplasmic membranemembrane Streptococcus bovis, Streptococcus bovis,
Enterococcus faecalis, Enterococcus faecalis, Enterococcus faeciumEnterococcus faecium
resist bile and high resist bile and high concentrations of concentrations of sodium chloridesodium chloride
Disease:Disease: urinary tract infectionurinary tract infection intra-abdominal intra-abdominal
abcessesabcesses wound infectionwound infection EndocarditisEndocarditis
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M antigens
proteins of the pilusproteins of the pilus sensitive to Pepsin & Trypsinsensitive to Pepsin & Trypsin soluble at pH 2soluble at pH 2 50 types50 types
Involved in rheumatic feverInvolved in rheumatic fever 5-8 types5-8 types Antibodies neutralize streptococcal infectionsAntibodies neutralize streptococcal infections
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PathogenesisPathogenesis
capsule -- non-immunogeniccapsule -- non-immunogenic M Protein -- antiphagocytic, M Protein -- antiphagocytic,
anticomplementaryanticomplementary Lipoteichoic acid (LTA):Lipoteichoic acid (LTA):
mediates adherence to epithelial cells mediates adherence to epithelial cells LTA binding proteinLTA binding protein
Host cell membrane:Host cell membrane: Deacylated LTADeacylated LTA
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EnzymesEnzymes
Streptokinase A & B:Streptokinase A & B: lyse blood clotslyse blood clots
DNA ase:DNA ase: depolymerase DNA in pusdepolymerase DNA in pus
Hyaluronidase:Hyaluronidase: hyaluronic acidhyaluronic acid
DPN aseDPN ase
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Lab diagnosisLab diagnosis
Gram stain -- good in cases of pyodermaGram stain -- good in cases of pyoderma fluorescent antibodyfluorescent antibody
detection of antibodies to Streptolysin O ASO detection of antibodies to Streptolysin O ASO 3-4 weeks after exposure3-4 weeks after exposure
Culture:Culture: swab the lesion directlyswab the lesion directly blood agar plates - hemolysisblood agar plates - hemolysis
ElizaEliza
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S. pneumoniaeS. pneumoniae
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Streptococcus pneumoniaeStreptococcus pneumoniae
Gram positive cocci in pairs, singles, short Gram positive cocci in pairs, singles, short chainschains
alpha hemolysis -- aerobicalpha hemolysis -- aerobic beta hemolysis -- anaerobicbeta hemolysis -- anaerobic capsule -- immunogenic (84 serotypes)capsule -- immunogenic (84 serotypes)
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Diseases:Diseases:
Pneumonia -- inflammation of the lungs Pneumonia -- inflammation of the lungs with exudation and consolidation with exudation and consolidation (solidification)(solidification)
SinusitisSinusitis MeningitisMeningitis BacteremiaBacteremia
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PathogenesisPathogenesis
virulence factor, capsule -- prevents phagocytosis virulence factor, capsule -- prevents phagocytosis Pneumolysin is a temperate and oxygen labile Pneumolysin is a temperate and oxygen labile
hemolysinhemolysin Purpura-producing principalPurpura-producing principal is released during cell is released during cell
autolysisautolysis Neuraminidase -- glycoproteins and glycolipidsNeuraminidase -- glycoproteins and glycolipids Autolysins, amidases -- autolyse peptidoglycan layerAutolysins, amidases -- autolyse peptidoglycan layer
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Mechanisms of PathogenicityMechanisms of Pathogenicity
aspiration of S. pneumoniae, an endogenous aspiration of S. pneumoniae, an endogenous oral organismoral organism
organism colonizes the oropharynxorganism colonizes the oropharynx epiglottal reflex, coughing is inhibitedepiglottal reflex, coughing is inhibited
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Lobar PneumoniaeLobar Pneumoniae
multiplication in the alveolar spacesmultiplication in the alveolar spaces viral infection frequently precedes viral infection frequently precedes
bacterial infectionbacterial infection highly invasive due to capsulehighly invasive due to capsule bacteremia commonbacteremia common Meningitis -- most often in childrenMeningitis -- most often in children Treatment:Treatment:
Penicillin, ErythromycinPenicillin, Erythromycin
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Laboratory DiagnosisLaboratory Diagnosis
sputum -- gram+ cocci, lancet sputum -- gram+ cocci, lancet shaped,capsule, may appear over-shaped,capsule, may appear over-decolourizeddecolourized
alpha-hemolytic, optochin sensitivealpha-hemolytic, optochin sensitive Quellung reaction -- specific antiserum to Quellung reaction -- specific antiserum to
capsular polysaccharidecapsular polysaccharide capsular antigen can be detected by very capsular antigen can be detected by very
sensitive immunologic testssensitive immunologic tests
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The EndThe End
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