Staphylococcus

Question 1

S. Aureus will test coagulase _____

Answer 1

Positive

Question 2

Most common causative agent of disease

Answer 2

S. Aureus

Question 3

_____ is a key player in the extracellular matrix function of adhesion of S. aureus.

Answer 3

Fibronectin

Question 4

Toxic oxidative substances released by PMNs (WBCs) to kill bacteria. Also damages host tissue (inflammation)

Answer 4

ROS (reactive oxygen species)

Question 5

Virulence factors of S. aureus:

Answer 5

1. Polysaccharide capsule- blocks phagocytosis
2. Protein A- blocks antibody function
3. Pore-forming toxins- pop PMNs and other cells leading to more damage and inflammation (Panton-Valentine Leukocidin)

Question 6

Syndrome where exfoliating toxins cause layers of epidermis to separate. (Toxins: Proteases with high-specificity for desmosomal proteins)

Answer 6

SSSS (Staphylococcal Scalded Skin Syndrome)

Question 7

TSST-1 is a ______ (causes an unregulated inflammatory response by activating high numbers of CD4 T cells)

Answer 7

Superantigen

Question 8

In Staphylococcal food poisoning, toxin is pre-formed in contaminated, unrefrigerated food. It is not an ______, rather an _____.

Answer 8

Infection

Intoxication

Question 9

Many strains of S. aureus secrete enterotoxins that are heat stable:

Answer 9

1. Enterotoxins A, B, C, D, E

2. Superantigens- cause intense peristalsis

Question 10

____ antimicrobial agents are inhibitory substrates for PBPs (Penicillin Binding Proteins- make peptidoglycan crosslinks). These include Penicillins, Cephalosporins, Carbapenems, Monobactams.

Answer 10

Beta-lactam

Question 11

MSSA (Susceptible) vs. MRSA: Since MRSA (Methicillin Resistant S. aureus) is resistant to Beta-lactam drug classes, ____ is frequently used to treat MRSA. It is a glycopeptide class antimicrobial drug.

Answer 11

Vancomycin

Question 12

Less than ___% of the population carry MRSA, but ___% of healthcare professionals carry it. Colonization sites include Nares, Axilla, and Groin.

Answer 12

1

5-15

Question 13

Staphylococcus:

1. Gram stain?
2. Oxygen dependence?
3. Can it be isolated? How?

Answer 13

1. Gram positive
2. Facultative Anaerobes
3. Yes. 42 valid species isolated by Catalase positive test and 7.5% NaCl growth

Question 14

S. Aureus diseases:

Answer 14

1. Integumentary and wounds
2. Bacteremia
3. Aspiration pneumonia
4. UTI
5. Toxic shock syndrome
6. Scalded skin syndrome
7. Food poisoning