Streptococcus

Q1: Which of the following test(s) may establish retrospective diagnosis of streptococcal infection?

A Anti-DNase B test

B ASO test

C Streptozyme test

D All of these

ANS:D - All of these

No answer description is available.

Q2: Streptococcus pyogenes can be differentiated from other haemolytic Streptococci on the basis of

A Bacitracin sensitivity

B Erythromycin sensitivity

C Aminoglycosides sensitivity

D Penicillin sensitivity

ANS:A - Bacitracin sensitivity

S. Pyogen is bacitracin sensitive while others be hemolytic.

Q3: Streptolysin O is

A antigenic

B oxygen-labile

C heat-labile

D all of these

ANS:D - all of these

No answer description is available

Q4: Which of the following condition is non-suppurative sequelae of Streptococcus pyogenes infections?

A Acute rheumatic fever

B Acute glomerulonephritis

C Erythema nodosum

D All of these

ANS:D - All of these

No answer description is available.

Q5: Individuals suffering from primary atypical pneumonia have agglutinins to

A Streptococcus MG

B S avium

C S mutans

D Enterococcus faecalis

ANS:A - Streptococcus MG

How it reacts with lipids of Streptococcus?

Q6: Which of the following test indicates the susceptibility to streptococcal pyrogenic exotoxin?

A Schick test

B Disk test

C ASO test

D Precipitation test

ANS:B - Disk test

The modification of the CAMP test for group B streptococci involved substituting a paper disk impregnated with partially purified beta-hemolysin for the staphylococcal culture that was the source of beta-hemolysin in the original test. The disk is placed onto a sheep blood agar plate beside the streak of Streptococcus being tested. The plate is then incubated aerobically at 35 degrees C.

A positive reaction consists of a lunar-shaped clear zone that appears within 24 h in the dark beta-hemolysin zone surrounding the disk. A double-blind study of 135 randomly coded streptococcal isolates showed complete agreement between the CAMP-disk test and the standard Lancefield precipitin test.

All group B streptococci tested had positive reactions, and all strains tested from streptococcal groups A, C, D, and G were negative. The CAMP-disk test is a simple and convenient way to identify presumptively group B streptococci.

Q7: The bacteria involved in the production of dental caries is/are

A Streptococcus mutans

B S sanguis

C Both (a) and (b)

D Streptococcus pyogenes

ANS:C - Both (a) and (b)

S.Sanguinis is abundant in the oral commensal which can cause disseminated human infections if it gains access to the blood stream.

Q8: Crystal violet blood agar is a selective medium for

A β-haemolytic streptococci

B Staphylococcus aureus

C Corynebacterium diphtheriae

D Mycobacterium tuberculosis

ANS:A - β-haemolytic streptococci

This is because other species of Streptococcus species and other gram positive organism are inhibited by sodium chloride.

Q9: The bacterial sore throat is caused by

A Staphylococcus aureus

B Haemophilus spp

C Streptococcus pyogenes

D Mycoplasma pneumoniae

ANS:C - Streptococcus pyogenes

Staph aureus also causes pharyngitis.

Q10: Cell wall protein of Streptococcus pyogenes crossreacts with human

A synovial fluid

B cardiac valves

C myocardium

D vascular intima

ANS:C - myocardium

Cell wall carbohydrate reacts with cardiac valves.

And cell wall protein reacts with the myocardium.

Q11: Which of the following cross-reacts with cell wall carbohydrate of Streptococcus pyogenes?

A Cardiac valves

B Synovial fluid

C Myocardium

D Vascular intima

ANS:A - Cardiac valves

Component of the cell wall of selected M type induce antibodies that react with cardiac muscle tissue.



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