Gram Positive Cocci

Question 1

Enumerate the clinically significant genera of Gram positive cocci.

Answer 1

STAPHYLOCOCCI
MICROCOCCI
STREPTOCOCCI

Question 2

3 most common species of Staphylococci

Answer 2

S. aureus
S. epidermidis
S. saprophyticus

Question 3

Describe the staphylococcus based on its arrangement

Answer 3

grape-like cluster

Question 4

Staphylococcus can grow on what environment? Tell the percentage.

Answer 4

7.5% - 10% Sodium Chloride

they are halophiles - loves saline environment

Question 5

Staphylococcus are resistant to what? How many units?

Answer 5

0.02 - 0.04 units of bacitracin (Taxo A)

Question 6

What is a catalase Test?

Answer 6

a presumptive test to differentiate staphylococci and micrococci from streptococci.

Question 7

What is the result of Staphylococcus and Micrococcus in Catalase Test?

Answer 7

POSTIVE

Question 8

Catalase test uses what reagent?

Answer 8

Hydrogen Peroxide

Question 9

How many Percent of hydrogen peroxide is used?

Answer 9

3%

Question 10

What is the principle of Catalase test?

Answer 10

The enzyme, catalase, will breakdown hydrogen peroxide into water and oxygen, forming bubbles/effervescent

Question 11

What indicates a positive result in catalase test?

Answer 11

Bubble formation/Effervescent

Question 12

What are the two methods used in catalase test?

Answer 12

tube and slide method

Question 13

When performing catalase test, colonies from what media should not be used? Why should it not be used?

Answer 13

BAP; it can lead to false positive result

Question 14

Despite considered as a normal flora, S. aureus can also cause what?

Answer 14

Toxin mediated diseases and Non-toxin mediated diseases

Question 15

Enumerate examples of Toxin mediated diseases

Answer 15

Food poisoning
Toxic Shock Syndrome
Scalded skin syndrome/Ritter’s Disease in newborn

Question 16

Food poisoning is caused by what virulence factor?

Answer 16

Enterotoxin A and B

Question 17

Toxic Shock Syndrome is caused by what virulence factor?

Answer 17

Pyrogenic Exotoxin C

Question 18

Pyrogenic Exotoxin C is also known as

Answer 18

Toxic Shock Syndrome Toxin - 1

Question 19

Exfoliatin can cause what disease?

Answer 19

Scalded skin syndrome/Ritter’s Disease in newborn

Question 20

Major Virulence Factor of Staphylococcus aureus?

Answer 20

COAGULASE

Question 21

Considered as the marker of virulence for S. aureus?

Answer 21

Coagulase

Question 22

Responsible for the resistance of S. aureus penicillin and other beta lactam antibiotic?

Answer 22

Beta-lactamase

Question 23

what is the action of beta lactams?

Answer 23

cell-wall inhibitors

Question 24

Purpose of Cephalosporinase test?

Answer 24

detect beta-lactamase production

Question 25

What substrate is used in cephalosporinase test?

Answer 25

Nitrocefin

Question 26

Positive result in cephalosporinase test?

Answer 26

pink to red

Question 27

Other name for hyaluronidase?

Answer 27

Duran Raynal Factor

Question 28

What is the action of hyaluronidase?

Answer 28

to enhance the ability of the microorganism to invade the tissue

Question 29

What virulence factor is responsible for the degradation of DNA?

Answer 29

DNAse/ Thermonuclease

Question 30

It decreases the viscosity of exudates in order to allow more mobility of the organism

Answer 30

DNAse/ Thermonuclease

Question 31

Other terms of Beta hemolysin

Answer 31

Sphingomyelinase C ; Hot-cold lysin

Question 32

Responsible for the beta hemolytic property of the S. aureus

Answer 32

Beta-hemolysin