[STREP TEST] STREPTOCOCCAL DISEASE Flashcards
What is the primary pathogen responsible for streptococcal diseases?
Streptococcus pyogenes (Group A Streptococcus).
What is the main serological test used for detecting streptococcal infections?
Anti-streptolysin O (ASO) test.
What is the ASO test used for?
Detects anti-streptolysin O antibodies in a patient’s serum.
What does ASO stand for?
Anti-streptolysin O.
What is the principle of the ASO titer test?
Neutralization reaction detecting the inhibition of hemolysis by ASO antibodies.
What is a normal ASO titer range?
0-125 IU/mL.
What does a high ASO titer indicate?
Recent or past streptococcal infection.
What type of antigen does the ASO test detect?
Streptolysin O, a toxin produced by Streptococcus pyogenes.
What diseases are associated with high ASO titers?
Acute rheumatic fever and post-streptococcal glomerulonephritis.
What is the specimen used for the ASO test?
Serum.
What is the principle of the ASO slide test?
Passive agglutination.
How does the ASO latex test work?
Latex particles coated with streptolysin O react with ASO antibodies causing agglutination.
What is the Streptozyme test?
A rapid test that detects multiple streptococcal antibodies.
What is the principle of the Streptozyme test?
Passive hemagglutination.
What antibodies does the Streptozyme test detect?
Anti-streptolysin O, anti-deoxyribonuclease B (ADN-B), anti-streptokinase (ASK), and anti-hyaluronidase (AH).
What are the advantages of the Streptozyme test?
Detects multiple streptococcal antibodies in a single test.
What is DNase B and why is it significant?
A bacterial enzyme that degrades DNA and is associated with streptococcal virulence.
How does the DNase B test help in streptococcal diagnosis?
Measures antibodies against DNase B to confirm streptococcal infections.
What is the principle of the DNase B test?
Enzyme immunoassay detecting DNase B-specific antibodies.
What are the common complications of Streptococcus pyogenes infections?
Acute rheumatic fever, post-streptococcal glomerulonephritis.
What is acute rheumatic fever?
An inflammatory disease affecting the heart, joints, and skin following a streptococcal infection.
How does streptococcal infection lead to acute glomerulonephritis?
Immune complex deposition in the kidneys following streptococcal pharyngitis or impetigo.
What are the clinical symptoms of post-streptococcal glomerulonephritis?
Hematuria, hypertension, and proteinuria.
What is the incubation period for streptococcal infections?
1-3 days.
What is the significance of a rising ASO titer?
Indicates an ongoing or recent streptococcal infection.
How does the ASO test differ from the Streptozyme test?
ASO detects anti-streptolysin O antibodies; Streptozyme detects multiple streptococcal antibodies.
Why is serial testing important in streptococcal serology?
Monitors antibody response over time to confirm active infection.
What is the role of C-reactive protein (CRP) in streptococcal infections?
A marker of inflammation elevated in streptococcal infections.
What is the principle of the CRP slide test?
Latex agglutination.
What specimen is used for CRP testing?
Serum.
How is the CRP test interpreted?
Agglutination indicates elevated CRP levels due to inflammation.
What is the function of streptolysin O?
Lyses red blood cells by forming pores in the membrane.
What is the function of streptokinase?
Converts plasminogen to plasmin, aiding bacterial spread.
What is the function of hyaluronidase in streptococcal infections?
Degrades hyaluronic acid, allowing bacterial invasion.
What is the role of M protein in streptococcal pathogenicity?
A major virulence factor that prevents phagocytosis.
What are the Lancefield groups of Streptococcus?
Groups A, B, C, D, F, G based on carbohydrate antigen classification.
Which Lancefield group does Streptococcus pyogenes belong to?
Group A.
What are the hemolytic patterns of streptococci?
Alpha, beta, and gamma hemolysis.
What type of hemolysis does Streptococcus pyogenes exhibit?
Beta-hemolysis.
What is the principle of the RF latex test?
Latex agglutination detecting rheumatoid factor.
What does a positive RF test indicate?
Suggests rheumatoid arthritis or other autoimmune diseases.
What is the function of rheumatoid factor (RF)?
An autoantibody directed against the Fc portion of IgG.
What are the limitations of the ASO test?
Low sensitivity in early infections and cross-reactivity with other conditions.
What are confirmatory tests for streptococcal infections?
DNA-based assays and culture confirmation.
How does molecular testing complement serodiagnostic testing for Streptococcus?
Identifies genetic material of Streptococcus, increasing diagnostic accuracy.
What are the advantages of serological tests over bacterial culture for streptococcal infections?
Faster diagnosis and detects past infections even when cultures are negative.
Why is early diagnosis of streptococcal infections important?
Prevents complications like rheumatic fever and glomerulonephritis.
What is the treatment for streptococcal infections?
Antibiotics, primarily penicillin or amoxicillin.
What antibiotics are commonly used for streptococcal infections?
Penicillin, amoxicillin, and cephalosporins.
How can streptococcal infections be prevented?
Hand hygiene, avoiding contact with infected individuals, and vaccination (if applicable).
