Part II: Gram Positive Cocci (Streptococci) Flashcards
Gram (+) cocci in chains/spherical to ovoid
STREPTOCOCCI
STREPTOCOCCI : Catalase
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STREPTOCOCCI : Motility and Special Requirement
Non motile
Capnophilic
Starting point in Streptococci Identification:
Hemolysis in BAP
Selective Media of Streptococci
Phenyl ethyl agar (PEA)
Medium of choice in Streptococci
Sheep’s Blood Agar
presumptive test for CATALASE (-); GRAM (+) COCCI
LAP (LEUCINE AMINO PEPTIDASE) Test
LAP : Substrate
Leucine-beta-napthylamide
LAP: Reagent
Cinnamaldehyde
LAP:
(+)(-) Result
(+) Red
(-) no color/yellow
classifiesStreptococci according to hemolysis that they
produce on BAP
Smith and Brown Classification
Can cause incomplete/partial
hemolysis on BAP
Greening of Agar
Alpha hemolysis
Can cause complete
hemolysis on BAP
Clear zones around colonies
Beta Hemolysis
Does not cause
hemolysis
Gamma hemolysis
- most significant
in identifying and classifying Beta Hemolytic Streptococci;
LANCEFIELD CLASSIFICATION
based on the extraction of C
carbohydrate from the Streptococcal cell wall
LANCEFIELD CLASSIFICATION
A.k.a. Group A Beta hemolytic Streptococci
S. pyogenes
Known as major throat pathogen
S. pyogenes
S. pyogenes : Clinical Significance
- Pharyngitis
- Scarlet Fever
- Necrotizing fascitis
- Erysipelas
Known as flesh-eating bacteria
S. pyogenes
Continuous Streptococcal infection may lead to
Rheumatic fever
Acute Glomerulonephritis (AGN)