Staphylococcus Flashcards by Randel Escobar

Habitat of S. aureus

Nasal passages, skin, oral cavity and intestinal tract

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Habitat of S. epidermidis

inhabitant of the skin

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Perfectly spherical Gram (+) cocci approx. 0.5 to 1u in
diameter

Staphylococcus

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A virulence factor that promote colonization of host tissues such as those that promote attachment to host

Surface proteins

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Staphylococcus have Surface proteins that promote attachment to host proteins like?

laminin and fibronectin

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A surface protein present on epithelial and endothelial
surfaces as well as
component of blood clots

Fibronectin

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A virulence factor of Staphylococcus which promotes attachment to blood clots and
traumatized tissues

Fibrinogen/fibrin binding surface protein

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A virulence factor of Staphylococcus which allows it to attach to collagen tissues

Collagen-binding factor

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These organisms that causes Infections associated with in-dwelling
medical devices such as IV catheters, prosthetic joints,
replacements heart valves

Staphylococcus

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TRUE or FALSE:
If material is in the body for long periods, fibrinogen is
degraded further promote bacterial attachment

FALSE:
If material is in the body for long periods, fibrinogen is degraded and no longer promote bacterial attachment

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What ligand becomes predominant in promoting attachment of Staphylococcus

Fibronectin

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surface polysaccharide of serotype 5 or 8

Capsular polysaccharide

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Capsule polysaccharide of Staphylococcus are called

microcapsule/slime layer

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TRUE or FALSE:
surface polysaccharide of Staphylococcus can only be visualized only by electron microscopy after antibody labelling

TRUE

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TRUE or FALSE:
Polysaccharide rapidly lost upon laboratory
subculture

TRUE

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What surface protein of S. aureus which
binds with IgG the wrong way by non-immune
mechanism

Protein A

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Protein A surface protein of S. aureus which binds to what antibody?

IgG

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Protein A binds with IgG the wrong way and disrupts what?

Opsonization and Phagocytosis

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toxin that specifically acts on polymorphonuclear leukocytes/wbc

Leukocidin

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Responsible for symptoms during infections

Protein toxins

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Membrane damaging toxins

Protein toxins

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What protein toxin produces fever

Pyrogens

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best characterized,
most potent membrane-damaging toxin; major virulence
factor

A–toxin

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binds to membrane of susceptible cells, its subunits oligomerize to form hexameric rings

A–toxin

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What blood cells have high affinity to A-toxin

platelets and monocytes

TRUE or FALSE: Delta-toxin trigger the production of inflammatory mediators that produce the symptoms of septic shock

FALSE: A-toxin

This toxin produces beta hemolysis

A-toxin

B-toxin contains what enzyme that damages membranes rich in this lipid

Sphingomyelinase C

B-toxin's Classical test is the lysis of?

Sheep RBC

Classical test of B-toxin done at a lower temperature range (4°C to 15°C) produces what type of lysis?

Beta hemolysis (Complete)

Classical test of B-toxin done at a lower temperature range (37°C) produces what type of lysis?

Alpha Hemolysis (Partial)

TRUE or FALSE: B-toxin's activity is influenced by temperature.

TRUE

Small peptide toxin produced by most strains of S. aureus

Delta-toxin

A phospholipase which role in disease is not known

Delta-toxin

2-component toxin that damages membrane (host cell) of susceptible cells

Gamma –toxin and leukocidin

Protein B and C form what type of toxin?

strong leukotoxin with poor hemolytic

Protein A and B form what type of toxin?

strong hemolytic and weakly leukotoxic

has potent leukotoxicity but non-hemolytic

Panton and Valentine Leukocidin

is an important factor in necrotizing skin lesions

Panton and Valentine Leukocidin

Causes dermonecrosis when injected subcutaneously in rabbits

Panton and Valentine Leukocidin

Give the two examples of Superantigens produced by S. aureus

Enterotoxins and Toxic shock syndrome toxin (TSST1)

Enterotoxins is a virulent factor of what serotype of S. aureus?

6 serotypes A, B, C, D, E and G

Cause diarrhea and vomiting

Enterotoxins

weakly related to enterotoxin and does not have emetic activity

Toxic shock syndrome toxin (TSST1)

Responsible for 75% of TSS including menstrual cases

Toxic shock syndrome toxin (TSST1)

stimulate T-cells without normal antigenic recognition, results to release of cytokines in large amounts

Toxic shock syndrome toxin (TSST1)

Causes scalded skin syndrome in neonates with widespread blistering and loss of epidermis

Epidermolytic (exfoliative) toxin

Epidermolytic (exfoliative) toxin has two forms what is it?

ETA and ETB

Has protease activity which acts upon the protein, targets protein in the skin

Epidermolytic (exfoliative) toxin

Targets protein important in maintaining the integrity of the epidermis

Epidermolytic (exfoliative) toxin

Extracellular protein which binds with prothrombin in host to form staphylothrombin

Coagulase

resulting to conversion of fibrinogen to fibrin and formation of clot in plasma

Coagulase

Traditional marker for identifying S. aureus not present in S. epidermidis

Coagulase

Plasminogen activator

Staphylokinase

Activates plasmin-like proteolytic activity which dissolves fibrin clot

Staphylokinase

important in abscesses where it could modify antibacterial lipids and prolong bacterial survival

fatty acid modifying enzyme (FAME)

What are the enzymes that provides nutrients for the bacteria

Proteases, lipases, deoxyribonuclease

also known as the spreading factor; found in muscle and bones

Hyaluronidase

hydrolyzes hyaluronic acid (cementing substance)

Hyaluronidase

Most important coagulase-negative staphylococci (CNS) which is a common common of the skin

S. epidermidis

Major cause of infections associated with prosthetic devices and catheters

S. epidermidis

Production of characteristic slime (biofilm)

S. epidermidis

TRUE or FALSE: S. aureus coagulase (-) but catalase (+), S. epidermidis coagulase and catalase (+)

FALSE

TRUE or FALSE: Staphylococcus spp. are mannitol fermenters

FALSE

TRUE or FALSE: ALL Staphylococcus spp. are salt tolerant

TRUE

DISEASE: a stump of spermatic cord after castration become infected, enlarged and sclerotic with pockets of pus containing granules similar to actinomycosis

Botryomycosis in horses

DISEASE: suppurative lesions in cattle, organisms colonize tips of teats

Mastitis

DISEASE: acute septicemia or bacteremia along with toxemia kills lamb; Ixodes ricinus

Tick pyemia in lambs

DISEASE: Purulent synovitis in poultry

Bumblefoot in Turkey

DISEASE: exudative dermatitis in rabbits and subcutaneous abscesses in older animals

Cutaneous staphylococcosis

What type of Staphylococcus sp. are most prevalent in dogs and carnivores

S. intermedius

What type of Staphylococcus sp. causes exudative epidermitis of swine Thru breaks on the skin

S. hyicus subsp. hyicus