MIDTERMS TOPIC 2 Flashcards
classification based on temperature requirement
academic or bergey’s classification
what are the 4 groups in bergey’s or academic classification?
- pyogenes grp
- viridans grp
- lactic grp
- enterococcus grp
45 (x)
37(/)
10 (x)
pyogenic grp
45 (/)
37(/)
10 (x)
viridans grp
45 (x)
37(/)
10 (/)
lactic grp
45 (/)
37(/)
10 (/)
enterococcus grp
what grp produce pus; mostly β-hemolytic
pyogenes grp
- not part of the Lancefield group: resist Lancefield
Precipitation Test - α-hemolytic or non-hemolytic
- normal biota in URT in humans
viridans grp
- non-hemoly=c with Lancefield N an=gen
- found in dairy products
- give one spp. that belongs to this grp
- lactic grp
- S. lactic
- normal of human intestine
- give one spp. that belongs to this grp
- enterococcus grp
- e. faecalis
classification based on the hemolytic pattern on BAP
smith and brown’s classification
- partial/incomplete hemolysis of RBC around colonies
- Culture: greenish or brownish discoloration around colony
alpha-hemolytic streptococci
- complete hemolysis of RBC around colony
- culture: clear zone around colony
beta-hemolytic streptococci
- exhibit NO hemolysis of RBC around colony
- Culture: RBC surrounding colony are not affected (no
change)
gamma-hemolytic streptococci
small area of intact RBCs
around colony surrounded by a wider zone of complete
hemolysis
a-prime or wide zone
- based on an=genic characteris=cs of GROUP-SPECIFIC C
SUBSTANCE, a cell wall polysaccharide - extraction of C carbohydrate from the streptococcal cell
wall by dilute acid and heating the suspension for 10 mins - mostly significant in classifying and identifying beta-hemolyti streptococci
lancefield classification
- not considered as a part of indigenous flora = pathogenic
- acquired through contaminated droplets released through coughing and sneezing
- resistant to drying and can be recovered from swabs
several hours after the collection - colonizes throat and skin on humans
S. pyogenes
- major virulence factor of S. pyogenes
- resist
phagocytosis and adherence of the
bacterial cell to mucosal cells
M protein
2 post-streptococcal dses?
- rheumatic fever
- acute glomerulonephritis
- aka FIBRONECTIN-BINDING
PROTEIN - adhesion molecule that mediates epithelial cell attachment
protein f
- adhesion molecule present in the cell wall that is responsible for the
adherence into respiratory
epithelial cells
lipoteichoic acid
o weakly immunogenic
o prevents opsonized phagocytosis by PMN or macrophages
o mask bacterial antigens
hyaluronic acid capsule
o causes lysis of fibrin clots
o binds plasminogen and activates
the production of plasmin
o allows bacteria to move from
clotted area (spread infection)
o Application: treatment of
pulmonary emboli, coronary artery,
and venous thromboses
streptokinase
