Immunology & Serology - Laboratory - ASO

Anti-Streptolysin O

Antibody response to his antibody is the most frequently used serologic indicator of a recent Streptococcal infection

Latex Agglutination Test

What is the name of the test used to detect for ASO and CRP in the serum?

Streptolysin O

It is the extracellular product of Group A Streptococci Streptococcus pyogenes that contributes to the pathogenicity of the organism.

Sterols

What part of the RBC membrane does Streptolysin O bind to?

Hemolysin

What type of extracellular product is Streptolysin O?

Antigenic

What characteristic of Streptolysin O causes it to elicit an immune response?

Anti-Streptolysin O

What is the specific antibody for Streptolysin O?

Group A Streptococci Streptococcus pyogenes

What bacteria produces Streptolysin O?

Beta-hemolysis

Group A Streptococci Streptococcus pyogenes hemolytic pattern on Sheep's blood agar

Gram-positive cocci

Group A Streptococci Streptococcus pyogenes gram staining reaction and morphology

Todd

Who discovered Streptolysin O in 1932?

Anti-Streptolysin O

The quantity of this antibody in a patient's serum will establish the degree of infection caused by Group A Streptococci.

Group A Streptococci Streptococcus pyogenes

What bacteria is a major cause of bacterial pharyngitis and childhood impetigo?

Bacterial pharyngitis, Childhood impetigo

What two infections are commonly caused by Group A Streptococci Streptococcus pyogenes?

Strep throat

Another name for bacterial pharyngitis

Bacterial pharyngitis

What is the throat infection caused by Group A Streptococci Streptococcus pyogenes?

Childhood impetigo

What is the skin infection caused by Group A Streptococci Streptococcus pyogenes?

M protein

It is a major virulence factor of Group A Streptococci Streptococcus pyogenes such that other strains that do not contain this cannot cause an infection.

C3

M protein is a major virulence factor of Group A Streptococci Streptococcus pyogenes because it can inhibit phagocytosis and it can limit the deposition of what complement on the surface of bacteria?

Pyrogenic exotoxins A, B, C

What virulence factors of Group A Streptococci Streptococcus pyogenes are responsible for the rash seen in Scarlet fever and contributes to its pathogenicity?

Streptolysin O, Deoxyribonuclease B, Hyaluronidase, Nicotinamide adenine dinucleotide, Streptokinase

Enzymes produced by Group A Streptococci Streptococcus pyogenes

Pharyngitis, Necrotizing Fasciitis, Streptococcal Toxic Shock Syndrome, Streptococcal pyoderma

Clinical manifestations of Group A Streptococci Streptococcus pyogenes

Pharyngitis

What clinical manifestation of Group A Streptococci Streptococcus pyogenes is known as sore throat?

Pharyngitis

What clinical manifestation of Group A Streptococci Streptococcus pyogenes is the swelling and reddening of the pharynx? It is characterized by the redness on the soft palate and petechiae at the back of the throat.

Necrotizing fasciitis

What clinical manifestation of Group A Streptococci Streptococcus pyogenes is known is a life-threatening infection which is why the bacteria is called as the "flesh-eating bacteria"?

Streptococcal pyoderma

What clinical manifestation of Group A Streptococci Streptococcus pyogenes is known as impetigo?

Streptococcal pyoderma

What clinical manifestation of Group A Streptococci Streptococcus pyogenes is characterized by vesicular lesions on the extremities that become pustular and crusted?

Upper respiratory tract, Skin

What are the 2 major sites of infection in humans for Group A Streptococci Streptococcus pyogenes?

Otitis media, Erysipelas, Cellulitis, Puerperal sepsis, Septic arthritis, Acute bacterial endocarditis, Meningitis

Other clinical manifestations of Group A Streptococci Streptococcus pyogenes infection

Sinusitis, Septic arthritis, Acute bacterial endocarditis, Meningitis

Which among the other clinical manifestations of Group A Streptococci Streptococcus pyogenes infection can only be a result of pharyngeal infection and not from skin infection?

Humans

Who are the only reservoir for Group A Streptococci Streptococcus pyogenes?

Person-to-person

Group A Streptococci Streptococcus pyogenes transmission

Acute rheumatic fever, Post-streptococcal glomerulonephritis

What are the 2 Group A Streptococcal sequelae?

Autoimmune condition

Group A Streptococcal sequelae usually starts of as what kind of condition because the antibodies produced against the organism starts to target the antigen on the other parts of the body?

Acute rheumatic fever

What Group A Streptococcal sequelae occurs only after upper respiratory tract infection?

Upper respiratory tract infection

Acute rheumatic fever as a sequelae of Group A Streptococcal infection only occurs after having what kind of infection?

1-3 weeks

Acute rheumatic fever latency after the onset of sore throat?

Fever, pain caused by inflammation in the joints, inflammation of the heart

Acute rheumatic fever symptoms

Acute rheumatic fever

What Group A Streptococcal sequelae is a cross-reactivity of antibodies produced against Streptococcal antigens and human heart tissue? There is a similar antigen found in the human heart tissue that mimics the M protein.

Post-streptococcal glomerulonephritis

What Group A Streptococcal sequelae occurs only after infection of either the skin or the pharynx?

Post-streptococcal glomerulonephritis

What Group A Streptococcal sequelae is most common in children between the ages of 2 and 12?

Skin or pharynx infection

Post-streptococcal glomerulonephritis as a sequelae of Group A Streptococcal infection only occurs after having what kind of infection?

2-12

Post-streptococcal glomerulonephritis is most common in children between what ages?

Hematuria, proteinuria, edema, hypertension, malaise, backache, abdominal discomfort

Post-streptococcal glomerulonephritis symptoms

Deposition of antibody-streptococcal antigen complexes in kidney resulting in glomeruli damage

Post-streptococcal glomerulonephritis mechanism

Scarlet fever

What diseases caused by Group A Streptococci Streptococcus pyogenes features a bright red rash that starts from the uppermost of the body (starting from the trunk to the extremities)?

Scarlet fever

What disease caused by Group A Streptococci Streptococcus pyogenes has the same manifestation for symptoms with pharyngitis or sore throat plus the rashes?

101°F Fever, Nausea, Vomiting, Headache, Abdominal pain

Scarlet fever symptoms

Scarlet fever

What disease only results from infections with Group A Streptococci Streptococcus pyogenes that is able to produce the erythrogenic toxin or exotoxin that is responsible for the rashes?

Sheep's blood agar

Culture medium for the laboratory diagnosis of Group A Streptococci Streptococcus pyogenes

Small translucent colonies surrounded by a clear zone of beta-hemolysis

Group A Streptococci Streptococcus pyogenes colonial characteristics on Sheep's Blood Agar

Lateral flow immunochromatographic assay

Rapid test kits used for the detection of Group A Streptococcal antigens

15-20 minutes

How long does it take for lateral flow immunochromatographic assays to give results?

Peak

In the detection of Streptococcal antibodies, the onset of clinical symptoms of Rheumatic fever or glomerulonephritis typically coincides with the ____ of antibody response.

Fourfold

If acute and convalescent phase sera are tested in parallel, a _____ rise in titer is considered significant.

Acute phase sera

This is the patient's serum collected during the first week or first 7 days of Group A Streptococci Streptococcus pyogenes infection.

Convalescent phase sera

This is the patient's serum collected after 2 weeks of Group A Streptococci Streptococcus pyogenes infection

Immunoglobulin G

What antibody starts to develop in the convalescent phase sera?

Immunoglobulin M

Primary response antibody

Immunoglobulin G

Secondary response antibody

laboratory

The value of the ASO titer should be compared with the reference range of the ________ if there is no acute phase sera.

Streptolysin O, Streptolysin S

What are the hemolysins of Group A Streptococci Streptococcus pyogenes?

Oxygen-labile, antigenic, causes sub-surface hemolysis

Characteristics of Streptolysin O

Oxygen-stable, non-antigenic, causes beta-hemolysis on the surface of the blood agar

Characteristics of Streptolysin S

Streptolysin O, Streptolysin S, Deoxyribonuclease A, B, C, D, Streptokinase, NADase, Hyaluronidase, Diphosphopyridine nucleotidase, Pyrogenic exotoxins

Group A Streptococci Streptococcus pyogenes exotoxin products

True

True/False

A serological evidence of a recent Group A Streptococci infection is based on a rising titer from acute to convalescent phase.

1-2 weeks

When do ASO titers increase after infection?

3-6 weeks

ASO titers peak between how many weeks following initial infection?

Passive agglutination

What is the principle of the latex agglutination for ASO?

Indirect agglutination

Other name for passive agglutination

Anti-Streptolysin O

What is detected in the latex agglutination assay for ASO?

Anti-Streptolysin O

What is the antibody in the latex agglutination assay for ASO?

Stabilized Streptolysin O

What is the antigen in the latex agglutination assay for ASO?

Streptolysin O

It is the antigenic enzyme produced by Group A Streptococci that can indicate a recent Streptococcal infection in patients suspected with rheumatic fever or post-streptococcal glomerulonephritis following a throat or skin infection.

Polystyrene latex, Bentonite, Charcoal, RBC, Latex, Gelatin

Carrier particles in the latex agglutination for ASO

Latex Agglutination for Anti-Streptolysin O

The test kit contains polystyrene latex particles, coated with stabilized Streptolysin O as antigen which reacts immunologically with the corresponding Anti Streptolysin O (ASO) antibodies of a patient or control serum. The positive reaction is indicated by a distinctly visible agglutination of the latex particles in the test ring of the reaction card.

Passive agglutination

What type of agglutination occurs when carrier particles mixed with an antigen, if added to patient's serum which may contain antibodies against that antigen, it will result to agglutination?

White latex particles with stabilized Streptolysin O, 0.95 g/L Sodium azide, 200 mmol/L Ammonium chloride, pH 8.2

Components of the ASO Latex Reagent

Human serum containing ASO >200 IU/mL

ASO control serum positive

Human serum containing ASO <200 IU/mL

ASO control serum negative

200 IU/mL

ASO detecting limit in the latex agglutination assay

100 rpm

Mechanical rotator speed for ASO latex agglutination test

2-8°C

ASO Latex Agglutination storage conditions for controls

Negative control

What control for ASO Latex Agglutination should show a homogenous solution?

Positive control

What control for ASO Latex Agglutination should agglutinate?

Latex reagent

What reagent for ASO Latex Agglutination should be added on both controls and patient sample?

Visible agglutination in the glass

What is the indication of deterioration for the reagent in ASO Latex Agglutination?

Presence of particulate matter

What is the indication of deterioration for the control in ASO Latex Agglutination?

Fresh, non-hemolyzed serum

ASO Latex Agglutination specimen

50 uL

ASO Latex Agglutination specimen volume

False

True/False

When mixing the reagent and specimen, the same applicator stick should be used to mix and spread over the entire area of the ring.

2 minutes

How long should the reagents, specimen, and controls be tilted back and forth after mixing in ASO Latex Agglutination?

Bright artificial light

Results of the latex agglutination cards should be read under what kind of light?

False-positive result

What type of result is interpreted if the agglutination card is read beyond 2 minutes?

800 IU/mL

False-negative results due to high dose effect are absent at least up to what ASO concentration?

Hemoglobin, Bilirubin, Rheumatoid factors, Lipemia

What are the different interferences in the ASO Latex Agglutination assay?

5 g/L

What concentration of hemoglobin can interfere with the ASO Latex Agglutination assay?

15 mg/dL

What concentration of bilirubin can interfere with the ASO Latex Agglutination assay?

300 IU/mL

What concentration of Rheumatoid factors can interfere with the ASO Latex Agglutination assay?

5 g/L

What concentration of lipemia can interfere with the ASO Latex Agglutination assay?