Catalase-NEGATIVE, Gram-POSITIVE Cocci

Question 1

leading cause of bacterial pneumonia and meningitis

Answer 1

Streptococcus pneumoniae

Question 2

virulence factor os Streptococcus pyogenes that is responsible for the B-hemolytic patternn in blood agars

Answer 2

Streptolysin O and S

Question 3

the immunogenic Strepolysin that is capable of lysing RBCs

Answer 3

Streptolysin O

Question 4

Streptocccus pyogenes can also be called the:

Answer 4

Flesh eating bacteria

Question 5

Toxin from Streptococcus pyogenes that is known to cause SCARLET FEVER

Answer 5

streptococcal pyrogenic exotoxins (SPEs)

• • associated with streptococcal pharyngitis and rashes on the face and upper trunk
• • erythrogenic toxin produced by LYSOGENIC STRAINS
• • heat labile

Question 6

other complications caued by Streptococcus pyogenes

Answer 6

Rheumatic Fever
acute glomerulonephritis

(post streptococcal diseases)

Question 7

type of protein that is associated with rheumatic fever

Answer 7

Class 1 M protein

Question 8

type of protein that is associated with acute glomerulonephritis

Answer 8

Class I or II M protein

Question 9

RHEUMATIC FEVER usually happens when it is followed by

Answer 9

Respiratory Tract Infections

– mediated by antibodies against S. pyogenes M protein tht cross-react with human heart tissue

Question 10

mechanisms of S. pyogenes to prevent the clearance of the disease

Answer 10

1. M protein + B-globulin H factor = failure to degrade C3b

2. M protein + fibrinogen = X alternate complement pathway activation

Question 11

enzyme found in all S. pyogenes strains that is capable of inactivating the chemotactic factor for neutrophils and monocytes

Answer 11

C5a peptidase (serine protease)

C5a is the chemotactic factor for neutrophils and monocytes

Question 12

the organisms that is known to cause bacterial memningitis in neonates

Answer 12

Streptcoccus agalactiae

Question 13

the organism that contains C polysaccharide

Answer 13

Streptococcus pneumoniae

– antiphagocytic capsule associated with the organism’s virulence

Question 14

organism that is commonly found in nosocomial infections

Answer 14

Enterococci

Question 15

the most commonly encountered Enterococcus spp. in nosoccomial infections

Answer 15

Enterococcus faecalis

Question 16

gene in Group B streptococci that is detected in polymerase reaction

Answer 16

CAMP factor (cfb gene)

Question 17

microscopic morphology of Streptococcus pneumoniae

Answer 17

lancet shaped (singes, pairs or in short chains)

Question 18

how to culture Abiotrophia and Granulicatella

Answer 18

BAM/CAM only with pyridoxal (vit B6)

— supplied by pyridoxal disk or cross streaking Staphylococcus; or by inoculation of Vit B6 supplemented culture meedia

Question 19

the most common media for the isolation of group A streptococcci

Answer 19

5% BAM with trimethoprim-sulfamethoxazole (SXT) — to supress the growth of normal flora

Question 20

Trimethoprim-Sulfamethoxazole inhhibits the growth of these organisms

Answer 20

Normal Flora

Grroup C, F, G B-hemolytic streptococci

Question 21

culture media that is used to detect group B streptococci (S. agalactiae) during pregnancy

Answer 21

1. Todd-Hewitt broth with antimicrobials (gentamicin, nalidixic acid and colistin)
   - - will suppress the growth of vaginal flora
2. LIM broth

Question 22

incubation conditions and duration of Streptococci

Answer 22

• facultative anaerobes (CO2 enriched environment)

- BAM/CAM in 5 - 10 % carbon dioxide

Question 23

at what condition in incubation is hemolysis in BAM better visualized?

Answer 23

at anaerobic conditions

Question 24

the method of inoculating the organisms in BAM or CAM in order to better visualize Hemolytic reactions

Answer 24

stabbing of the inoculating LOOP several times into tthe medium

Question 25

the screening test that can differentiate A-hemolytic cocci

Answer 25

vancomycin susceptibility test