Streptococcus pyogenes Group A Streptococcus
S. pyogenes GAS contains hyaluronidase. What is the function of hyaluronidase in S. pyogenes virulence?
1. break down connective tissue...to... 2. facilitate the spread through tissue...
In Scarlet Fever (causative agent - S. pyogenes), pt. presents with a confluent erythematous sandpaper-like (fine, blanching) rash. Where does the begin and then radiate towards?
1. chest and neck...spreads outward...
SpeA causes polyclonal activation of T cells in Toxic Shock Like Syndrome (TSLS) in pts. infected with S. pyogenes. How do patients with S. pyogenes present?
1. acute fever... 2. shock... 3. multi-organ failure... 4. Painful, pre-existing skin infections... 5. positive blood cultures...
What two titers are used to diagnose Post-Streptococcal glomerulonephritis?
1. Antistreptolysin O ASO... 2. Anti-DNase B...
S. pyogenes is associated with glomerulonephritis, a type III hypersensitivity reaction What is post-streptococcal glomerulonephritis?
1. Circulating immune complex deposition (anti-Strep binds strep Ag) deposition in glomerular basement... 2. immune complex deposition leads to... 3. Nephritic syndrome
What are the minor JONES criteria (FAIP)?
1. Fever... 2. Arthralgia... 3. Increased serum levels of acute phase reactants... 4. prolonged PR interval of EKG
What are the 4 classic findings of Scarlet Fever?
1. Fever... 2. Pharyngitis (sore throat)... 3. Strawberry Tongue... 4. Confluent erythematous sandpaper-like (fine, blanching) rash
What of the signs of S. pyogenes generally precedes rheumatic fever? What of the signs of S. pyogenes does NOT generally precede rheumatic fever?
1. GAS tonsillopharyngitis... 2. GAS skin infections (nonbullous impetigo, erysipelas, cellulitis)
What are the major JONES criteria?
1. Joints... 2. O or carditis... 3. Nodules... 4. Erythema marginatum rash... 4. Sydenham chorea
S. pyogenes GAS is encapsulated. What is the function of the capsule?... What is the composition?
1. antiphagocytic properties... 2. hyaluronic acid
S. pyogenes is associated with 3 autoimmune diseases. What are the 3 autoimmune diseases associated with S. pyogenes?
1. Rheumatic Fever (Type II hypersensitivity)... 2. Post-strep glomerulonephritis (Type III hypersensitivity)... 3. Pediatric autoimmune neuropsychiatric disorder associated with streptococci syndrome (PANDAS)
Compare S. pyogenes (GAS) to S. agalactiae (GBS) in regards to bacitracin antibiotic.
1. S. pyogenes is bacitracin sensitive... 2. S. agalactiae is bacitracin resistant...
S. pyogenes synthesizes exotoxin A and C. What are the names of Exotoxin A and C? What type of conversion due to Exotoxins A and C? What is mechanism of action of Exotoxin A and C?
1. Spes, scarlet fever toxins, erythrogenic toxins... 2. lysogenic conversion... 3. superantigens
S pyogenes GAS contains streptolysin O and streptolysin S. What is the function of Streptolysin O? What is the function of Streptolysin S?
1. Streptolysin O destroys RBCs... 2. Streptolysin S destroys WBCs.
What are 2 ways to detect recent S. pyogenes GAS infections?
1. antistreptolysin O ASO... 2. anti-DNase B
In Scarlet Fever (causative agent - S. pyogenes), pt. presents with a confluent erythematous sandpaper-like (fine, blanching) rash. What are 3 types of rasshes that can occur under the umbrella of confluent erythematous sandpaper-like (fine, blanching) rash?
1. circumoral pallor... 2. pastia lines... 3. rash may be followed by desquamation starting with fingers in 2nd week
S. pyogenes GAS contains streptokinasae. What is the function of streptokinase in S. pyogenes virulence?
1. converts plasminogen to plasmin... 2. plasmin results in fibrinolysis...(degradation of fibrin)... 3. facilitates spread of S. pyogenes through tissue
What are the requirements of diagnosis of Rheumatic Fever?
1. evidence of recent GAS infection... 2. Two major or Two minor Jones Criteria...JONES FAIP
S. pyogenes is the most common bacterial cause of sore throat, pharyngitis. What are the 4 clinical findings of patients with S pyogenes pharyngitis?
1. fever... 2. malaise... 3. sore throat... 4. enlarged cervical lymph nodes
What are the structural characteristics of Streptococcus pyogenes Group A Strep GAS
1. gram positive... 2. cocci... 3. Beta-hemolytic on blood agar... 4. bacitracin sensitive 5. encapsulated... 6. Pyrrolidonyl arylamidase PYR test positive...
What are the virulence factors of Streptococcus pyogenes Group A Strep GAS?
1. hyaluronidase positive... 2. m protein positive. 3. streptokinase positive... 4. exotoxins A, B, C... 5. streptolyin O and Streptolysin S...
S. pyogenes GAS contains M protein. What is the function of M protein in S. pyogenes virulence? How many 100+ immunotypes of M protein are there?
1. inhibits opsonization and phagocytosis by blocking complement... 2. 100+ immunotypes of M protein
S. pyogenes causes 3 pyogenic infections. What are the 3 pyogenic infections S. pyogenes causes?
1. pharyngitis (strep throat)... 2. non-bullous impetigo... 3. erysipelas/cellulitis
What are the 3 modes of transmission of S. pyogenes GAS?
1. respiratory droplets... 2. food... 3. direct inoculation of skin...
2 types of streptococcal infection preced Post-streptococcoal glomerulopnephritis. What are the 2 types of infections that precede post-streptococcal glomerulonephritis?
1. skin streptococcal infection... 2. pharyngeal streptococcal
S. pyogenes GAS is the part of the normal flora of 2 sites. What are the 2 sites S. pyogenes GAS is part of the normal flora?
1. skin... 2. oropharynx
What patient population is most affected by Rheumatic Fever? When does this population present with Rheumatic Fever?
80% children... present 2-3 weeks post-infection
S. pyogenes causes non-bullous impetigo. What are the 2 clinical findings of non-bullous impetigo?
At site of inoculation... 1. pustular lesions... 2. honeycomb-like crusts
What disease is hyaluronidase associated with?
Cellulitis
How does cellulitis differ from erysipelas?
Cellulitis is a deeper process that has irregular borders
S. pyogenes causes erysipelas and cellulitis. What is erysipelas? What is cellulitis? What 3 features do they share?
Erysipelas: superifical S. pyogenes skin infection... Cellulitis: deepr process extends to subcutaneous tissue... 1. Red... 2. Tender... 3. Warm
In Scarlet Fever (causative agent - S. pyogenes), pt. presents with strawberry tongue. In what other condition, would a patient present with Strawberry Tongue?
Kawasaki disease (mucocutaneous lymph node syndrome)... inflammation in walls of blood vessels throughout body.
What is toxic shock-like syndrome (TSLS)? What is its mechanism of action?
Life threatening illness precipitated by S. pyogenes... 1. S. pyogenes skin infection = cellulitis... 2. systemic release of exotoxin A SpeA... 3. exotoxin A causes polyclonal activation of T cells
What are pustular lesions?
pustules are small collection of pus in epidermis (top layer of skin) or dermis (bottom layer)... simply, pustule is a collection of pus.
S. aureus causes Toxic Shock Syndrome TSS... S. pyogenes causes Toxic Shock Like Syndrome... What is the difference between S. aureus TSS and S. pyogenes TSLS?
Pts. with S. aureus TSS do NOT present with... 1. painful preexisting skin infections... 2. positive blood cultures
S. pyogenes (GAS) is pyrrolidonyl arylamidase PYR test positive. What is PYR test? What 2 types of bacteria does it identify?
Rapid identification test... 1. S. pyogenes... 2. Enterococci...
S. pyogenes is NOT the most common cause of non-bullous impetigo. What is the most common cause of non-bullous impetigo?
S. aureus
What is the most common cause of bacterial sore throat?
S. pyogenes
S. pyogenes secretes exotoxins A, B, C. Systemic release of exotoxins A, B, and C are associated with what disease?
Scarlet Fever
What 3 diagnostic tests evidence recent GAS infection?
Serology for... 1. Antistreptolysin O titer... 2. anti-DNase B titer... 3. bacterial cultures
What is the name of Group A Streptococcus?
Streptococcus pyogenes
S. pyogenes causes Scarlet Fever. What 3 pyrogenic exotoxins does S. pyogenes systemically release to cause Scarlet Fever?
Systemic release of... 1. SpeA Exotoxin A... 2. SpeB Exotoxin B... 3. SpeC Exotoxin C...
S. pyogenes GAS secretes exotoxin A SpeA. What disease is SpeA Exotoxin A associated with?
Toxic Shock Like Syndrome
What are pastia lines?
accenutation of rash in linear pattern along skin folds
S. pyogenes is associated with Rheumatic Fever, a type II hypersensitivity reaction. What is Rheumatic Fever?
cross-reactivity between S. pyogenes antigens esp. M proteins and self-antigens... Ab against M proteins attack self-antigen via mimicry
S. pyogenes GAS secretes exotoxin B SpeB. What is exotoxin B SpeB? What disease is SpeB Exotoxin B associated with?
protease precursor activated to cysteine protease... necrotizing fascitis
What is circumoral pallor?
rash spares nasolabial triangle and chin
What is nephritic syndrome?
syndrome comprising signs of nephritis, kidney disease involving inflammation
What is the gold standard of diagnosis S. pyogenes GAS infection whether pyogenic or toxin-mediated?
throat or skin culture