Staph

Question 1

5 strains of Staphylococci

Answer 1

S. Aureus (30% of population w/out symptoms), S. Epidermidis, S. saprophyticus, S. hameolyticus, S. Lauduensis

Question 2

Characteristics of Staphylococci

Answer 2

can grown in high salts, facultative anaerobe, produces CATALSES (Streptococci are Catalses negative)

Question 3

How to determine who gave patient Staph

Answer 3

Pulsed Gel Electrophoresis

Question 4

Role of Pathogenicity of Capsule

Answer 4

adherence, immune evasion

Question 5

Role of Pathogenicity Peptidoglycan

Answer 5

antigenic (bring immune cells) –> attracts polymorphic neutrophiles (PMN) –> IL-1

Question 6

Role of Pathogenicity techoic acid

Answer 6

helps bind fibronectin and mucosal surfaces to colonize

Question 7

Role of Pathogenicity Protein A

Answer 7

bind Fc and IgG–> evade complement. binds Von Willerbrand Factor (VWF) –> platelet adhesion. Binds TNF –> recruiting leukocytes

Question 8

Role of Pathogenicity Clumping factor

Answer 8

bound coagulases that binds fibrinogen (snow globe/slat plasma = positive)

Question 9

Role of Pathogenicity altered penicillin binding proteins

Answer 9

Proteins inside cell that have affinity for Beta Lactam so it doesn’t do damage

Question 10

Secreted Virulence Factors

Answer 10

Enzymes (localized, helps established

Question 11

Virulence Enzyme

Answer 11

Catalase = Brakes down H2O2 (bear foam = positive test), in Staph but not in Steph

Cogulase = binds fibrinogen + CRF –> fibrin (clumping of plasma = positive)

Staphylokinase = digests fibrin

Penicillinase = binds penicllin and stops it from entering porins

Hyaluronidase = hydrolize hyaluronic acid

Lipases and Nuclease

Question 12

Virulence Toxins that target tissues and individual cells

Answer 12

alpha Toxin = alpha hemolysisn, make pore in cell membrane

beta toxins = sphingomyhelinase C, works with alpha toxin –> tissue damage. Allows S. Aureus to multiple in presence of inflammatory response

Leukocidin = permeablizes membranes of PMN and macrophages (Panton-Valentine leukocidin is related to MRSA)

Exfoliatin = associated with Staphylococcal scalder skin syndrome (SSSS) and byllous impetigo. acts between granular prickle cell layer, T-cell mitogen, targets desmoglein 1

Question 13

Staph Food Poisoning

Answer 13

Rapid onset (4-6h), due to pre-formed toxins, relatively quick resolution (24hs), resistant to boiling, resistant to GI enzymes

Mainly in meats, custard, mayonnaise

higher number of incidents in certain months

Question 14

Virulence Toxins that have superantigen-like activity (brings in lot of cytokines)

Answer 14

Enterotoxins - type A-E most associated with food

Toxic shock syndrome toxin-1 (TSST) = only found in Staph bacteria. can be lethal, induces TNFalpha/beta and interferons

Question 15

Furuncle & Folliculitis

Answer 15

large pimples/zits

Question 16

Carbuncle

Answer 16

fusion of furuncle to make big one

Question 17

MRSA abscess

Answer 17

large abscess

Question 18

bullous impetigo

Answer 18

blisters of skin

Question 19

impetigo

Answer 19

skin leasions

Question 20

Scaled Skin syndrome

Answer 20

Top layer of skin peals off (between stratum granulosum and stratum mspinosum)

Due to exfoliatin

Question 21

Bacteremia = Septus

Answer 21

Spread or seeding of bacteria through bloodstream

Endocarditis - S. aureus, S. epidermidids, S. lagdunensis

Question 22

S. Epidermidid

Answer 22

normal flora of skin, often infects prosthetic devices

Question 23

S. saprophyticus

Answer 23

coagulase negative, mainly acts as pathogen in UTI only, resistance to novobiocin (used to distinguish from S. Epidermidid which is sensitive to it)