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

Outline Definition Extracellular products Diseases suppuration intoxications

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

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

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

Staphylococcus aureus produces the enzyme Endonuclease

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

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

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

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

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

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

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

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

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

Deep Tissue Abcesses Often resist antibiotics Surgical intervention Drainage Antitoxins

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

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

Platelet Damage by Toxins

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

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

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

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

The End