Micro - Staphylococci

Question 1

Staphylococcaceae is the _________

Answer 1

Family

Question 2

Staphylococcus is the _________

Answer 2

Genus

Question 3

Which species of staphylococcus is coagulase-positive?

Answer 3

Staphylococcus aureus

Question 4

Which species of staphylococcus, that we specifically learned about, are coagulase-negative?

Answer 4

• *S. epidermidis
• S. saprophyticus
• S. lugdunensis*

Question 5

Staphylococcus resembles some members of which other genus?

Answer 5

• Micrococcaceae
• *specifically Rothia (Stomatococcus) and Micrococcus

Question 6

Staphylococcaceae will have what Gram stain morphology?

Answer 6

Gram-positive cocci forming in grape-like clusters

Question 7

• Staphlyococcus* typically grow under what culture conditions?
• Facultative aerobic
• Facultative anaerobic
• Aerobic
• Anaerobic

Answer 7

Facultative anaerobic

(not picky- O₂/CO₂/aerobic/anaerobic)

Question 8

What media will Staphylococcus typically grow on? (4)

Answer 8

• BAP
• CHOC
• CNA
• PEA

Question 9

TRUE or FALSE

Staphylococcus generally have nutritional requirements

Answer 9

FALSE

generally, Staphylococcus have no nutritional requirements

Question 10

What Staphylococcus species?

• opaque, smooth colonies
• white-light yellow pigment
• beta hemolytic (usually)

Answer 10

Staphylococcus aureus (AKA SA or S. aureus)

Question 11

Impetigo, folliculitis, and furuncles are all considered non-invasive diseases caused by which Staphylococcus?

Answer 11

Staphylococcus aureus

Question 12

What are 3 examples of non-invasive diseases caused by S. aureus?

Answer 12

• Impetigo
• Furuncle
• Folliculitis

Question 13

Abscesses and osteomyelitis are considered invasive diseases caused by which Staphylococcus species?

Answer 13

S. aureus

Question 14

What are two invasive diseases caused by S. aureus?

Answer 14

• Abscess
• Osteomyelitis

Question 15

Food poisoning, scalded skin syndrome, and toxic shock syndrome are diseases that may be caused by which Staphylococcus species?

Answer 15

S. aureus

Question 16

What are three toxogenic diseases that may be caused by Staphylococcus aureus?

Answer 16

• Toxic shock syndrome
• Scalded skin syndrome
• Food poisoning

Question 17

What type of species?

• Opaque, smooth colonies
• Grey-white pigment
• Usually Gamma hemolytic

Answer 17

Coagulase Negative Staph (CNS)

Question 18

S. lugdunensis and S. epidermidis are known to cause which type of infection?

Answer 18

Endocarditis

Question 19

S. saprophyticus is known to cause which type of infection?

Answer 19

Urinary tract infection

Question 20

When testing to identify Staphylococci, which test is ONLY used for urine isolates?

Answer 20

Novobiocin

Question 21

If a Staphylococci species is resistant to novobiocin it can presumptively be called what?

Answer 21

S. saprophyticus

Question 22

Opaque, smooth, grey-white colonies

Gamma hemolytic

Catalse +

Coagulase =

Novobiocin resistant

Answer 22

Staphylococcus saprophyticus

Question 23

Opaque, smooth, grey-white colonies

Gamma hemolytic

Catalase +

Coagulase =

Novobiocin susceptible

Ornithine +

Answer 23

Staphylococcus lugdunensis

Question 24

Ornithine decarboxylase:

When bacteria metabolize amino acids/proteins, what is produced?

Answer 24

Alkaline products

Question 25

What does a positive ornithine decarboxylase test appear as?

Negative?

Answer 25

Positive = Purple (alkaline)

Negative = Yellow (acid)

Question 26

Mannitol salt agar (MSA) is considered what type of media?

Answer 26

Selective and differential

Question 27

Mannitol salt agar inhibits most of what gram-negative organisms and many gram-positive organisms due to what?

Answer 27

High salt concentration (7.5%)

Question 28

If mannitol is fermented on an MSA agar, what is produced? What does this do to the agar?

Answer 28

Acid is produced when mannitol is fermented causing a pH drop that turns the agar from red to yellow

Question 29

TRUE or FALSE

S. aureus will grow red colonies with red zones on MSA

Answer 29

FALSE

S. aureus ferments mannitol causing the growth of yellow colonies with yellow zones

Question 30

Which coagulase negative staphylococcus species is the most commonly isolated species, especially from cases of prosthetic valve endocarditis?

Answer 30

S. epidermidis

Question 31

Which coagulase negative staphylococcus species is isolated from urinary tract infections, especially in young, sexually active women?

Answer 31

S. saprophyticus

Question 32

Which coagulase negative staphylococcus species can cause an aggressive form of endocarditis?

Answer 32

S. lugdunensis

Question 33

This test differentiates staphylococci (+) from streptococci (=)

Answer 33

Catalase

Question 34

Reagent used for catalase testing

Answer 34

Hydrogen peroxide

H₂O₂

Question 35

Which organism will produce a pseudocatalase?

Answer 35

Enterococci

Question 36

Species that resembles staph except the gram-positive cocci tend to form in tetrads

Answer 36

Micrococcus species

Question 37

What species?

Creamy, opaque, bright lemon-yellow color

Gamma hemolytic

Answer 37

Micrococcus species

Question 38

What species:

Creamy, opaque, lemon-yellow gamma hemolytic colonies

GPC in tetrads

Catalase +

Coagulase =

Bacitracin susceptible

Furazolindone resistant

Modified Oxidase +

Answer 38

Micrococcus species

Question 39

This species is also known as “sticky staph”

Answer 39

Rothia mucilaginosis

Question 40

What species:

Gram positive cocci in clumps and tetrads

Opaque grey-white, gamma hemolytic, sticky colonies

Catalase =

Answer 40

Rothia mucilaginosus

Question 41

What type of coagulase is found with the slide test?

Answer 41

Bound coagulase (clumping factor)

Question 42

What is the catalase reaction for staph?

Answer 42

Positive

Question 43

Coagulase Slide Test:

What is the ID of the microorganism tested?

Answer 43

Positive - S. aureus

Question 44

What type of coagulase is found with the tube test?

Answer 44

Free coagulase