1. Hugh B. Fackrell Filename: staph.ppt
Staphylococcus
Hugh B. Fackrell
Filename: staph.ppt

2. Outline Definition Extracellular products Diseases suppuration
intoxications

3. Staphylococcus Gram +ve cocci in clusters
catalase +ve facultative anaerobes
sensitive to lysostaphin endopeptidase
resistant to lysozyme
ribitol or glyercol teichoic acids

4. Staphylococcus: structure
Gram positive spheres in grape-like clusters
Staphylo= grapes
Coccus = spheres

5. Extracellular Products of Staphylococci
TOXINS
Hemolysins
Leucocidin ( Leukocidin)
Enterotoxins
Exfoliative toxins
TSS toxin
ENZYMES
DNAse
Coagulase
Fibrinolysin
Lipases
Hyaluronidase

6. Staphylococcus aureus produces the enzyme Endonuclease

7. 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

8. 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

9. 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

10. Major Staphylococcal Pathogens
Staphylococcus aureus
infections & intoxications
Staphylococcus epidermidis
“stitch abcesses”
Staphylococcus saprophyticus
urinary tract infections

11. 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

12. Predisposing factors Break in the skin Chronic diseases
operations, burns, abrasions
blockage of sweat glands
Chronic diseases
cancer, diabetes, cirrhosis
Staphylococcal pneumonia

13. Staphylococcal diseases
Suppurative Diseases
pus
infiltration of WBC of polymorphonuclear leucocytes
Toxic poisonings

14. Staphylococcal Suppurative Diseases
boils, furuncles, carbuncles
wound infections
deep tissue abcesses
osteomyelitis
pneumonia, empyema
(intrapleural abcesses)
endocarditis, pericarditis
meningitis
purulent arthritis

15. Staphylococcal mastitis
Udder infections in dairy cattle
Penicillin resistant Staphylococci
Before antibiotics
Streptococcus group B & Group C

16. Deep Tissue Abcesses Often resist antibiotics Surgical intervention
Drainage
Antitoxins

17. Staphylococcal Intoxications
Enterotoxin
food poisoning
Toxic shock syndrome
Hemolysins
Epidermolytic toxin
“scalded skin syndrome”
Leucocidin

18. 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

20. Platelet Damage by Toxins

22. Staphylococcal Food Poisoning
Secreted protein
produced at room temp
produced aerobically and anaerobically
milk & meat products excellent media
Food handlers - carriers

23. Staphlylococcal Food Poisoning Signs & Symptoms
Nausea
Abdominal pain
Projectile vomiting
Diarrhea
Onset: average 3 hours
1-6 hours
Duration: 24 hours

24. Enterotoxin Several different forms Protein 24,000 MW Resistant to
acids
proteases in digestive tract
boiling for 2 hours
Gene carried by lysogenic phage

25. Toxic Shock Syndrome First reported 1980
young women during menstruation
tampons containing methacrylate supported growth of S. aureus and production of toxin
Shock & death

26. The End