Streptococcus Flashcards
T/F: Streptococcus is a gram + bacteria
true
Streptococcus pyogenes _____ -forming
pus
Some streptococci are typically seen as diplo-cocci: _____ _____.
Streptococcus pneumoniae
_-______on blood-agar plates causes clearing at and around colonies in Streptococcus pyogenes.
B-hemolysis
beta
_-_______ shows greening due to partial lysis of erythrocytes in S.mitis and S.pneumoniae.
a-hemolysis
alpha
a-hemolysis (alpha) is associated with what two bacteria?
S.mitis and
S.pneumoniae
B-hemolysis (beta) is associated with what bacteria?
Streptococcus pyogenes.
_______ degrades hemoglobin turning it to a green hue.
pneumolysin
Green color sheen has given the name ______ to many α- hemolytic Streptococci like the caries-causing: S.mutans, S.mitis, S.salivarius, S.sanguis
viridens
What two Streptococcal classification groups perform hemolysis?
Group A ( S.pyogenes)
group B ( S.galactiae)
M protein - cell wall component, >100 serotypes, membrane- anchored: is an important virulence factor
- anti-M antibodies prevent infection of S.pyogenes but many serotypes. So protective immunity is type-specific
- M protein binds keratinocytes, the main cell type in outer skin layer.
• M protein binds fibrinogen, blocking surface from complement system
components
• M protein binds complement control proteins
• Inhibits formation of
opsonins by complement
cascade
Virulence factors of Streptococcal bacteria ???? (couldn’t find if this was the broad category or a specific type of Streptococcal bacteria.)
_______ : antibodies are ineffective against glycocalyx-covered surface antigens
capsule
_______ also shows adhesion for fibronectin and strong adhesion to keratinocytes (skin)
M Protein
M protein anti-complement action through _____ _.
Factor H
Capsular ___ _______ destroys opsonizing C3b complement opsonization
C3 peptidase
__ _____: (cell surface) binds Fc of IgG, preventing phagocytosis based on FcReceptors
G protein
_____ ________ cleaves the complement componenet into inactive fragments
C3b peptidase
C5a peptidase are seen in ____ _ Streptococci
Group A
Inactive complement cehmotoxin ___ activate surface of plasminogen to plasmin and cleave of C3b.
C5a
What is an example of a membrane-damaging toxin disease?
streptococcus pyogenes
What is the name of the toxin released by streptococcus pyogenes?
streptolysin O
What is characteristic of a disease caused by streptococcus pyogenes
accumulation of pus
What is the mechanism of a disease caused by streptococcus pyogenes
inserts into memebranes, forming pores that allow fluids to enter.
lysis of erythrocytes (direct lysis; basis of β-hemolysis) and
of phagocyte lysosomal membranes (indirect lysis of leukocytes)
streptolysins S, O:
Overrides the specificity of the T-cell response
Superantigens
Which bacteria is an example of a superantigen in certain strains?
streptococcus pyogenes
What is the name of the disease caused by streptococcus pyogenes superantigens?
streptococcal toxic shock
What is the name of the toxins that cause disease beacue of streptococcus pyogenes superantigens?
streptocoocal pyogenic exotoxins
Scarlet fever
Streptococcus pyogenes
What is the virulence factor of scarlet fever?
Virulence factor: a superantigen SPE
Streptococcal Pyrogenic Exotoxins
skin infections of the face arms and legs.
Pyoderma (impetigo)
red skin
erysipelas
bullae
blister
_____ ______ can Progress to deep, systemic
infection leads to multi-organ
failure and death.
streptococcal gangrene
What is result of streptococcal gangrene?
necrotizing fasciitis
Acute Pharyngitis
strep throat
What are two serious results of Acute Pharyngitis?
glomerulonephritis
rheumatic fever
rheumatic fever is caused by what type of sensitivity?
type II
glomerulonephritis is caused by what type of sensitivity?
type III
Acute rheumatic fever can cause what two things?
myocarditis and arthritis
non-suppurative sequela with some strains • <10% of population is susceptible • fever is non-responsive to penicillin because disease is autoimmune • high frequency of reoccurrence
Acute Rheumatic Fever:
Group B, β-hemolytic (<2% non-hemolytic), chain-like growth, aerobic, polysaccharide capsule
Normal occurrence in the lower gastrointestinal tract. Does not cause disease in healthy people
- pneumonia in neonates (neonates: <7 days of birth)
- bacteremia and meningitis (neonates: >7 days of birth)
- urinary infections, bacteremia (pregnant women)
Neutralizing antibodies against group B polysaccharide Ag develop quickly and protect. (maternal Ab s prevent infection of neonate)
Streptococcus agalactiae
T/F: enterococcus Faecalis is a gram + bacteria.
true
___ ____ possesses high, multiple antibiotic resistances (plasmid and chromosomal)*
enterococcus Faecalis
_____ _____ mostly effects the elderly with long hospitalizations. (high nosocomial risk antibiotic resistance)
enterococcus Faecalis
α-hemolytic
Gram+
diplococci
Streptococcus pneumoniae
for ______ _______ Only encapsulated strains ( smooth colonies) are virulent
Streptococcus pneumoniae
high carrier rates for S. Pneumoniae
capsular vaccine available
pneumococcal Pneumonia
an enterobacterium
often resistant to antibiotics
fatal nosocomial pneumonias
no vaccine available
Klebsiella pneumoniae
no vaccine available
Mycoplasmal Pneumonia
virulence factors for ____ _____ include
alpha-hemolysis
capsule
secretory IgA proteases
S.pneumoniae virulence factors
Streptococcal pneumoniae can lead to_____
meningitis
