Staphylococci

Front 1

Staphylococci:
-Gram +/-?
-Catalase?
-Motile?
-Classification of O2 Metab?
-Host Relationship?

Back 1

-gram +
-catalase positive
-nonmotile
-facultative
-opportunistic pathogen

Front 2

S. aureus:
-Most frequently found where?
-Coagulase?
-Spread by?
-Other Characteristics?

Back 2

-most frequently isolated nosocomial pathogen (hospital acquired infection)
-coagulase positive
-most virulent staphylococcal species
-spread thru direct person to person contact or exposure to contaminated fomites (cannot invade thru skin)
-can survive on dry surfaces for long periods of time

Front 3

S. aureus:
Toxins?

Back 3

-cytotoxins
-exfoliative toxins
-enterotoxins
-toxic shock syndrome toxin-1

Front 4

S. aureus:
Toxins:
Cytotoxins:
-Sub-types?
-Attacks which cells?

Back 4

-alpha, beta, gamma, delta toxins and PV
-toxic for many types of cells

Front 5

S. aureus:
Toxins:
Exfoliative Toxins:
-2 Forms?
-Mode of Action?
-Causes?

Back 5

-2 forms: ETA (heat stable, on chromosome); ETB (heat labile, on plasmid)
-mode: serine protease
-causes staphylococcal scalded skin syndrome (SSSS)

Front 6

S. aureus:
Toxins:
Enterotoxins:
-Characteristics?
-Mode of Action?
-Causes?

Back 6

-characteristics: heat stable, resists GI enzymes
-mode: superantigen
-causes food poisoning

Front 7

S. aureus:
Toxins:
Toxic Shock Syndrome Toxin-1 (TSST-1):
-Characteristics?
-Mode of Action?
-Causes?

Back 7

-char: heat stable, protease resistant
-mode: superantigen
-causes toxic shock

Front 8

S. aureus:
Virulence Factors:
Enzymes

Back 8

-coagulase
-catalase
-hyaluronidase
-staphylokinase
-lipase
-nuclease
-penicillinase
(Count Chocula Has a Stye from Licking Needles of Penicillin)

Front 9

Coagulase

Back 9

converts fibrinogen to firbin, causing blood to clot; prevents phagocytosis

Front 10

Catalase

Back 10

catalyzes removal of H2O2

Front 11

Hyaluronidase

Back 11

hydrolyzes hyaluronic acid in CT, spreading staphylocci in tissue (invasin)

Front 12

Staphylokinase (Fibrinolysin)

Back 12

dissolves fibrin clots (invasin)

Front 13

Lipase

Back 13

hydrolyzes lipids; important for invasion of cutaneous and subcutaneous tissue (invasin)

Front 14

Nuclease

Back 14

hydrolyzes DNA; pathogenic fxn unclear
*useful in identifying S. aureus

Front 15

Penicillinase

Back 15

hydrolyzes penicillins (B-lactam resistance)

Front 16

S. aureus:
Virulence Factors:
Structural Components & Their Fxns

Back 16

-glycocalyx: inhibits phagocytosis; adherence
-peptidoglycan: endotoxin activity
-teichoic acids: adherence
-protein A: only in S. aureus; inhibits Ab mediated immune clearance; inhibits opsinization

Front 17

S. aureus:
Diseases:
Cutaneous Infections

Back 17

-impetigo: most common skin infection amongst kids
-folliculitiis: infection of hair follicles; Stye= @ base of eyelid; Furuncle (boil)= extensive form
-carbuncles: multiple furuncles together

Front 18

S. aureus:
Diseases:
Toxin Mediated Diseases

Back 18

-food poisoning: caused by ingestion of heat stable enterotoxins
-Staph. scalded skin syndrome: caused by exfoliative toxins
-toxic shock syndrome: caused by TSST-1; excessive cytokine production-> fever, rash, shock

Front 19

S. aureus:
Diseases:
Systemic Diseases

Back 19

-bacteremia: spread of bact. into blood; can cause infection in any organ (e.g. endocarditis [heart] and osteomyelitis [bone])
-pneumonia

Front 20

S. epidermidis:
-Biofilm Found Where?
-Virulence Factor?
-Causes?

Back 20

-biofilm found on invasive medical devices
-VF: glycocalyx
-causes endocarditis in valve replacement surgery; prosthetic joint infection
(epiderm=outside->surface of medical devices; outside of cell is VF)

Front 21

S. saprophyticus
-Causes?

Back 21

2nd most common cause of UTI

Front 22

Staphylococci:
Lab Diagnosis (Culture):
For 3 Species:
-Blood Agar?
-Novobiocin Sensitivity?
-Mannitol Fermentation?

Back 22

-S. aureus: beta hemolytic; NB sensitive; +mannitol ferm.
-S. epidermidis: gamma hemolytic; NB sensitive; no mannitol ferm
-S. saprophyticus: gamma hemolytic; NB resistant; no mannitol ferm