BACS

Question 1

<p>Staphylococcus</p>

Answer 1

<p>Characteristics: Gram+ cocci, catalase+</p>

Question 2

<p>Staphylococcus aureus</p>

Answer 2

<p>O2 can be used</p>

Question 3

<p>catalase</p>

Answer 3

<p>Reduces the potential of phagocytes to kill</p>

Question 4

<p>coagulase</p>

Answer 4

<p>The tissue-invasive potential of staphylococcal infections is directly
proportional to coagulase production (S.aureus; not in other Staph. species).
• coagulase binds prothrombin: fibrinogen is cleaved 􀀃 anti-phagocytic fibrin coating</p>

Question 5

<p>clumping factor</p>

Answer 5

<p>fibrinogen-binding protein: cell surface proteins that bind to foreign
materials (like sutures) and to extracellular matrix.</p>

Question 6

<p>protein a</p>

Answer 6

<p>Anti-phagocytic, competes with neutrophils for Fc portion of opsonizing IgG􀀂s
(on cell surface of S.aureus but not on other staphylococcal strains)</p>

Question 7

<p>staphylokinase</p>

Answer 7

<p>converts plasminogen to plasmin, increasing invasion by digesting
fibrin clots and cleaves C3b and IgG to inhibit phagocytosis</p>

Question 8

<p>Hemolysins</p>

Answer 8

<p>α-, β-, γ-, and δ-toxins are all hemolysins: lyse erythrocytes (lab phenomenon)</p>

Question 9

<p>Empyema:</p>

Answer 9

<p>Empyema: Collection of pus in a naturallyexisting
anatomical cavity (e.g. lungs)</p>

Question 10

<p>pyogenic infections</p>

Answer 10

<p>pus-forming (massive amounts of neutrophils and other leukocytes are
lysed by bacterial factors (e.g. leukocidin) and release their lysosomal
contents in attempting phagocytic killing of the staphylococci).</p>

Question 11

<p>pyogenic infections</p>

Answer 11

<p>folliculitis
furuncles
carbuncles
(systemic)
bacteremia
fever</p>

Question 12

Superantigens

Answer 12

Overides T cell specificity.

Question 13

Enterotoxins

Answer 13

Heat Stable. Cooking doesn’t work!

Question 14

Toxic Shock Syndrome

Answer 14

Productions of cytokines=inflammation. Mass Activation of t-cells. Heat Stable

Question 15

Exfoliative toxin

Answer 15

Heat stable: Heat Liable Plasmid

Question 16

TSS: Toxic Shock Syndrome

Answer 16

Increased oxygenation of vagina by tampons, and

foreign surface adhesion, caused massive growth

Question 17

SSSS: Staphylococcal Scalded Skin Syndrome
Ø exfoliative toxins A, B cause loss of layers of the skin in SSSS
Nester 􀀁04 Fig. Murray􀀁05 Fig.22-5
Neutralizing Ab

Answer 17

exfoliative toxins A, B cause loss of layers of the skin in SSSS
Nester 􀀁04 Fig. Murray􀀁05 Fig.22-5
Neutralizing Ab

Question 18

Nosocomial a Staphylococci

Answer 18

surgery, implant & instrument risk

Question 19

Endocarditis:

Answer 19

acute: 60% S.aureus
• if artificial heart valves: 80% S.epidermidis
S.epidermidis: dental extraction risk

Question 20

S. Aureus Epidemiology

Answer 20

skin + mucosa +
aerosols
surface survival
(hospital instruments,
implants)
􀀃􀀁nosocomial􀀂
(hospitalacquired)
high temperature
(40ºC) and salt
resistant

Question 21

Other Staphylococci like S.epidermidis or S.saprophyticus
• Thick cell wall, slime capsule, (S.saprophyticus: urease secretion → acute cystitis
• Opportunistic hospital pathogens (instruments, catheters, heart valves)

Answer 21

Coagulase─ : Other Staphylococci like S.epidermidis or S.saprophyticus
• Thick cell wall, slime capsule, (S.saprophyticus: urease secretion → acute cystitis
• Opportunistic hospital pathogens (instruments, catheters, heart valves)