L14 ( Lecture numbers are wrong btw ) : streptococci Flashcards
what classification of bacteria is streptococci and how are they arranged ?
gram positive bacteria in chains
how does streptoccoci react to :
coagulation test
catalase test
negative on both
in what aerobic conditions do streptococci grow?
they are facultative anaerobes meaning they grow both in the presense of oxygen and in its absence
bacteria are subdivided based on ___
C-carbohydrate antigen on their cell wall (A-U)
which bacteria falls under group A Beta-hymolytic streptococci ?
S. pyogenes
which bacteria falls under group B Beta-hemolytic streptococci ?
S. Agalacitae
which streptococci species is responsible for 90% of pharyngitis cases?
S. pyogenes
what component of S.pyogenes is responsible for inhibition of opsonization and cell lysis ?
M-protein
which components of S. pyogenes are responsible for adhesion ?
lipoteichoic acid
factor F ( fibronectin binding proteins )
which components of S.pyogenes are responsible for spread of organism through tissue ?
streptokinase
hyloronidase
SPE-A + SPE-C Result in___
fever , and red rassh seen in scarlet fever
SPE-A causes ____
toxic shock syndrome
SPE-B is present in -
“flesh eating “ necrotizing fascites
what cytolytic toxin of streptococci induces formation of anti-bodies?
Streptolysin O
what cytolytic toxin of streptococci is responsible for hemolysis ?
Streptolysin S
pathogenicity of S.pyogenes ::
pharyngitis
tonsillitis
sinusitis
otis media
cellulitis
necrosing fascitis
polydermal impetigo and eryspl—
what is the most common strep disease?
strep/sore throat
describe impetigo
honey colored crusts
how is strep throat spread?
saliva / nasal secretions
what is the incubation period of strep throat ?
2-4 days
S. pyogenes also causes:
-endocardidits (puerperal fever )
-myositis
-acute rheumatic fever ( 2 weeks after infection )
-glomerulonephritis (2-3 weeks after infection )
glomerulonephritis developed 2-3 weeks after s.pyogenes infection is an example of which type of hypersensitivity ?
type III hypersensitivity ( antibodies against streptolysin O )
what lab test can differentiate S.pyogenes from S.agalactiae?
sensitivity test against bacitracin :
S.pyogenes is sensitive while S. agalactiae is resistant
which streptococcal bacteria is part of normal flora of vagina and lower GIT ?
S. agalactiae (5-30% of women )
what component protects S.agalactiae bacteria from phagocytosis ?
polysaccharide capsule
pathogenicity of S. agalactiae ::
neonatal meningitis
purperal sepsis
pneumonia
S. agalactiae is CAMP test ____
positive
Group D streptococcal bacteria can be categorized into 2 groups , which are ?
enterococcus
non-enterococcal
examples of enterococcal bacteria :
S. fecalis
S. faecium
(UTI , intra-abdominal infections , pelvic infections )
they are normal flora in the GIT lower tract
(opportunistic/ nosocomial infections )
example of non enterococcal bacteria :
S. Bovis (S. gallocyticus)—causes endocarditis especially in patients with colon carcenoma
Give examples if alpha hemolytic streptococcal bacteria .
S. pneumoniae
S. viridans
what’s the shape /arrangement of S.pnumoniae ?
Lanceloale capsulated bicocci
normal inhabitants of 5-40% of peoples upper resparatory tract
give an example of a virulence factor of S. Pnumoniae .
IgA protease ( to protect itself since in enters through respiratory tract which contains a lot of secretions and therefore , IgA)
Which streptococci could be non-hemolytic as well as alpha hemolytic ?
S. viridans
where are S. VIRIDANS USUALLY FOUND IN NORMAL FLORA?
oral cavity and nasopharengeal flora
what is the most common cause of sub-acute bacterial endocarditis >?
S. viridans
which streptococci involves brain absesses ?
S. viridans and peptostreptococci
which streptoccoci are involved in dental caries ?
S. viridans
what lab test can differentiate between S. viridans and S. pnumoniae ?
sentitivity to optochin :
S.. viridans are resistant while S.pnumoniae is sensitive
give an example of an anaerobic streptoccoi ?
peptostreptococci ( grows in microarophillic conditions as well
where are peptostreptococci normally present ?
normal flora of mouth , gut , and female genital tract
