bacterial serology (streptococcal)

Question 1

The Streptolysin O Antigen is fixed on the surface of the latex particles. These latex particles are mixed with the patient’s diluted serum on a slide and rotated.

Answer 1

anti-streptolysin O (ASO) latex agglutination test

Question 2

conditions that are the consequence of a previous disease or injury

Answer 2

sequelae

Question 3

a neutralization test that can demonstrate recent streptococcal infection.

Answer 3

anti-DNase B

Question 4

ASO titer

• The ASO titer begins to increase approximately (?) days after infection and peaks after (?) to (?) weeks.
• Principle: (?), SLO is added to serial dilutions of patient serum, along with group O RBCs as indicator cells.
• ASO titer is reported as the (?) of highest dilution that shows no hemolysis & is expressed in (?) units.

Answer 4

• 7
• 4, 6
• neutralization
• reciprocal
• todd

Question 5

Patient antibodies (if developed due to past infection with Streptococcus pyogenes) neutralize the hemolytic activity of the streptolysin O (SLO) reagent. As a result, when red cells are added, SLO will be incapable of lysing the said cells (no hemolysis).

Answer 5

ASO test

Question 6

• SLIDE AGGLUTINATION SCREENING TEST FOR DETECTION OF ANTIBODIES TO SEVERAL STREPTOCOCAL ANTIGENS.
• SHEEP RBC’S COATED W/ STREPTOLYSIN, STREPTOKINASE, HYALURONIDASE, DNAse, so that ANTIBODIES to any streptoccal antigen can be detected

Answer 6

streptozyme testing

Question 7

• Healthy adults have ASO titers of (?) Todd units, with the usual titer decreasing after (?) years of age.
• A (?) rise in titer above a previous level is of greater significance than a single titer

Answer 7

• <166
• 50
• 30%

Question 8

Streptococcal pyoderma, characterized by vesicular lesions on the extremities that become pustular and crusted.

Answer 8

impetigo

Question 9

• caused by a strain of S. pyogenes that produces an erythrogenic toxin, which results in a characteristic rash. Fever and sore throat are also present.
• Distinct rash initially appears on the neck and chest and then spreads all over the body.
• results from infection with a GAS that elaborates streptococcal pyrogenic exotoxins (erythrogenic toxins).

Answer 9

scarlet fever

Question 10

streptolysin O enzymes

Answer 10

• DNase B
• hyaluronidase
• NAD
• streptokinase

Question 12

Upper respiratory tract infections caused by (?):
a. Sore Throat
b. Pharyngeal Edema

Answer 12

S. pyogenes

Question 13

Cross-reactions of antibodies produced against streptococcal antigens and human heart tissue

Answer 13

acute rheumatic fever

Question 14

Symptoms include fever, chills, severe sore throat, headache, tonsillar exudates, petechial rash on the soft palate, and anterior cervical lymphadenopathy

Answer 14

pharyngitis

Question 15

Deposition of antibody-streptococcal antigen complexes in kidney results in damage to glomeruli

Answer 15

glomerulonephritis

Question 16

streptolysin O or S

• Is a non-antigenic, oxygen-stable enzyme.
• It causes hemolysis by disrupting the selective permeability of the RBC membrane.

Answer 16

streptolysin S

Question 17

Pyrogenic exotoxins A, B, and C are responsible for the rash seen in (?) and also appear to contribute to pathogenicity

Answer 17

scarlet fever

Question 18

ASO test

• Red cell control = (?)
• SLO reagent control = (?)

Answer 18

• no hemolysis
• complete hemolysis

Question 19

Gram positive cocci, Beta-hemolytic, Divided to serogroup A through O

Answer 19

streptococcal sero

Question 20

contain lipoteichoic acid, important in the adherence of the organism to human epithelium and the initiation of infection

Answer 20

fimbrae

Question 21

streptolysin O or S

• bacterial toxin produced by virtually all strains of S.pyogenes;
• released during infection as indicated by antibody production to it;
• Molecular weight = 70 000;
• in its reduced state, brings about the lysis of red and white blood cells
• Is an oxygen-labile enzyme that causes hemolysis by binding to cholesterol in the RBC membrane.
• It is antigenic, and the presence of antibodies to SLO is an indicator of recent streptococcal infection.

Answer 21

streptolysin O

Question 22

Manifestation of S.pyogenes Infection

Answer 22

• acute RF
• glomerulonephritis

Question 23

MAJOR VIRULENCE FACTOR of S.pyogenes; cell protein found in association with hyaluronic capsule

Answer 23

M protein

Question 25

mediates epithelial cell attachment,

Answer 25

protein F

Question 26

Skin infections caused by (?) include:
a. Cellulitis
b. Impetigo
c. Erysipelas

Answer 26

S. pyogenes