Lecture 7: Cocci

Question 0

What are the top ten medically relevant cocci?

Answer 0

Strep:
Group A, Group B
Pneumococci
Viridans
Enterococci 

Staph:
S. aureus
S. epidermatis
S. saphrophyticus

Neisseria:
N. meningitides
N. gonnorhoeae

Question 1

What are the three genuses of cocci?

Answer 1

Streptococci
Staphylococci
Neisseria

Question 2

In what formation do staphylococci grow? Are they catalase + or - ?

Answer 2

Clumps

Catalase +

Question 3

Which staphylococci are coagulase +?

Answer 3

S. Aureus

Question 4

Which staphylococci are coagulase -?

Answer 4

S. Epidermatis

S. Saphrophyticus

Question 5

Is S. Aureus hemolytic?

Answer 5

Yes. Beta hemolytic

Question 6

Of which staphylococcus is protein A a virulence factor? What does it do?

Answer 6

A. Aureus

Binds immunoglobins

Question 7

Does a. Aureus have a capsule?

Answer 7

Yes

Question 8

Of which staphylococcus are the toxins coagulase, protein A, enterotoxemia, exfoliatin, leukocidin, and TSS toxin?

Answer 8

S. Aureus

Question 9

What is the reservoir for S. Aureus?

Answer 9

~30% of people have it on skin and in nose

Question 10

How is S. Aureus transferred?

Answer 10

Direct contact or through fomites

Question 11

Is S. epidermatis coagulase + or -?

Answer 11

Coagulase -

Question 12

Is S. Epidermidis hemolytic?

Answer 12

No

Question 13

What is the reservoir of S. Epidermidis?

Answer 13

Normal flora of skin and mucous membranes

Question 14

How is S. Epidermidis transmitted?

Answer 14

Attaches to nylon and plastic

Piercings, catheters, Shunts

Question 15

Is s. Saphrophyticus coagulase + or -?

Answer 15

Coagulase -

Question 16

Is S. Saphrophyticus hemolytic?

Answer 16

No

Question 17

What staphylococci causes UTIs, but does so less frequently than does G- bacilli?

Answer 17

S. Saphrophyticus

Question 18

Are staphylococci G+ or G-?

Answer 18

G+

Question 19

Are streptococci G+ or G-?

Answer 19

G+

Question 20

Are streptococci catalase + or -?

Answer 20

Catalase -

Question 21

Which group of cocci is classified by lancefield group and have pili in the cell wall?

Answer 21

Streptococci

Question 22

What does the lancefield group indicate?

Answer 22

Antisera to carbohydrate antigens of the cell wall

Question 23

Which streptococci species have NO lancefield group?

Answer 23

Viridans, S. Pneumoniae, peptostreptococcus

Question 24

What type of hemolysis does S. Pneumoniae show?

Answer 24

Alpha

Question 25

What structure is both an antigen and the virulence factor for S. Pneumoniae? How does it demonstrate both characteristics?

Answer 25

Polysaccharide capsule Prevents phagocytosis But stimulates opsonizing antibody

Question 26

What is the reservoir for S. Pneumoniae?

Answer 26

Throat of 5-50% of people

Question 27

What are the three species of Viridans streptococci?

Answer 27

S. Viridans S. Sanguis S. Mutans

Question 28

What type of hemolysis do Viridans streptococci show?

Answer 28

Alpha hemolysis

Question 29

Which species of streptococci are optochin resistant?

Answer 29

Viridans streptococci

Question 30

Enzymes which metabolize extracellular polysaccharides, and acids are virulence factors of which species of streptococci?

Answer 30

Viridans

Question 31

Where is Viridans streptococci' natural reservoir?

Answer 31

Mouth

Question 32

What is one species of Group A strep?

Answer 32

S. Pyogenes

Question 33

Are groups A and B strep hemolytic?

Answer 33

Both are beta hemolytic

Question 34

Which group of streptococci - a or b - is resistant to bacitracin?

Answer 34

B is resistant | A is susceptible

Question 35

Pili, encoded by a pathogenicity island, M protein, and many toxins (streptokinase, streptodornase, hyaluronidase, pyrogenic toxin, eruthrogenic toxin) are virulence factors of which species of streptococci?

Answer 35

Group A strep

Question 36

Streptolysin O is used for what clinical purpose?

Answer 36

Diagnosis of strep A

Question 37

What is one species of group B strep?

Answer 37

A. Agalactiae

Question 38

Does group B strep test cAMP + or -?

Answer 38

cAMP+

Question 39

What is the main virulence factor of group B strep?

Answer 39

Capsule

Question 40

What are the reservoir and transmission of group b strep?

Answer 40

Vaginal tract of 25% women | Transmitted to baby before or at birth

Question 41

What type of hemolysis does enterococcus fecalis display?

Answer 41

None - non-hemolytic

Question 42

Where is enterococcus fecalis normally found, and what does it cause as a pathogen?

Answer 42

Normal flora of colon | Abdominal abscesses, UTI, endocarditis

Question 43

What type of hemolysis do peptostreptococci display?

Answer 43

None - non-hemolytic

Question 44

What are peptostreptococci's normal reservoirs?

Answer 44

Mouth, resp tract, female genital tract, bowel | Not primary pathogens

Question 45

Which genus of cocci is G-?

Answer 45

Neisseria

Question 46

Which genus of cocci is grown on chocolate agar?

Answer 46

Neisseria

Question 47

Which genus of cocci are oxidase +, have LOS endotoxin in membrane, and use IgA protease to help attach to surfaces?

Answer 47

Neisseria

Question 48

Which species of neisseria ferments maltose and has a polysaccharide capsule?

Answer 48

N. Meningitides

Question 49

Which species of neisseria does not ferment maltose and lacks a capsule?

Answer 49

N. Gonnorhoeae

Question 50

What are the reservoir and transmission of n. Meningitides?

Answer 50

Respiratory tract of 5% of people | Transmitted by droplets

Question 51

Which species of neisseria have pili and can be found in neutrophils?

Answer 51

N. Gonnorhoeae

Question 52

What species is a G+ coccus, catalase+, coagulase +

Answer 52

S. aureus | only coagulase+ staph we have learned

Question 53

What coccus species is G+, coagulase-, bacitracin resistant

Answer 53

Group B strep

Question 54

What species is G- diplodocus and has pili?

Answer 54

N. Gonnorhoeae

Question 55

Which species is a G- diplococcus, has capsule, ferments maltose?

Answer 55

N. Meningitides

Question 56

Which species is G+ coccus, grows in chains?

Answer 56

Streptococci

Question 57

What species is G+ diplococcus, isolated from a patient with a cough

Answer 57

Streptococcus Pneumoniae

Question 58

What is a coccus, alpha-hemolytic, resistant to optochin?

Answer 58

Viridans streptococci

Question 59

What is a coccus, beta-hemolytic, CAMP+, isolated from neonate at autopsy?

Answer 59

Group B strep