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Staphylococcus
Hugh B. Fackrell
Filename: staph.ppt
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Outline
Definition
 Extracellular products
 Diseases

 suppuration
 intoxications
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Staphylococcus
Gram +ve cocci in clusters
 catalase +ve facultative anaerobes
 sensitive to lysostaphin endopeptidase
 resistant to lysozyme
 ribitol or glyercol teichoic acids

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Staphylococcus: structure
Gram positive spheres in grape-like clusters
 Staphylo= grapes
 Coccus = spheres

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Extracellular Products of
Staphylococci
TOXINS
 Hemolysins
 Leucocidin ( Leukocidin)
 Enterotoxins
 Exfoliative toxins
 TSS toxin
ENZYMES
 DNAse
 Coagulase
 Fibrinolysin
 Lipases
 Hyaluronidase
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Staphylococcus aureus produces
the enzyme Endonuclease
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Staphlylococcal Coagulase
Coagulase: enzymes that cause clotting of
blood plasma
 Measured by

 tube
test (Free coagulase)
 slide test (Bound coagulase)

Differentiation of Staphylococcal pathogens
 S.aureus
coagulase positive
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Coagulase vs Fibrinolysin
Competing Enzymes
Coagulase: forms clots
 Fibrinolysin: dissolves clots

Staphylococcus produces coagulase early
 protection against phagocytosis
 When cell numbers high make fibrolysin
 break out of protection
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Resistant to bile salts

Most strains grow in the
presence of 40% bile salts
 colonize

intestine
Most strains grown the
presence of 15% NaCl
 Colonize
the skin
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Major Staphylococcal Pathogens

Staphylococcus aureus


infections & intoxications
Staphylococcus epidermidis
 “stitch

abcesses”
Staphylococcus saprophyticus
 urinary
tract infections
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Staphylococci are
NOT highly invasive

S aureus:50% are carriers


found in nose area
S. epidermidis: universal
 present

on skin
95% have immunity to
Staphylococci
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Predisposing factors

Break in the skin
 operations,
burns, abrasions
 blockage of sweat glands

Chronic diseases


cancer, diabetes, cirrhosis
Staphylococcal pneumonia
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Staphylococcal diseases

Suppurative Diseases
 pus
 infiltration
of WBC of polymorphonuclear
leucocytes

Toxic poisonings
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Staphylococcal Suppurative
Diseases
boils, furuncles, carbuncles
 wound infections
 deep tissue abcesses
 osteomyelitis
 pneumonia, empyema

 (intrapleural
abcesses)
endocarditis, pericarditis
 meningitis
 purulent arthritis
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Staphylococcal mastitis
Udder infections in dairy cattle
 Penicillin resistant Staphylococci
 Before antibiotics

 Streptococcus
group B & Group C
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Deep Tissue Abcesses
Often resist antibiotics
 Surgical intervention
 Drainage
 Antitoxins
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Staphylococcal Intoxications

Enterotoxin
 food
poisoning
Toxic shock syndrome
 Hemolysins
 Epidermolytic toxin

 “scalded

skin syndrome”
Leucocidin
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Staphylococcal Hemolysins
Discovered because they
Destroy RBCs
 4 types

 alpha:
lethal cardiovascular
 beta: “ hot cold” sphingomyelinase

aggregates platelets
 gamma:

slightly dermonecrotic
lethal in rabbits
 delta:
bee venom
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Platelet Damage by Toxins
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Staphylococcal Food Poisoning

Secreted protein
 produced
at room temp
 produced aerobically and anaerobically
milk & meat products excellent media
 Food handlers - carriers
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Staphlylococcal Food Poisoning
Signs & Symptoms

Symptoms
 Nausea
 Abdominal
pain
 Projectile vomiting
 Diarrhea

Onset: average 3 hours


1-6 hours
Duration: 24 hours
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Enterotoxin
Several different forms
 Protein 24,000 MW
 Resistant to

 acids
 proteases
in digestive tract
 boiling for 2 hours

Gene carried by lysogenic phage
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Toxic Shock Syndrome
First reported 1980
 young women during menstruation
 tampons containing methacrylate supported
growth of S. aureus and production of toxin
 Shock & death

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The End
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