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Published byAlannah Logan Modified over 9 years ago
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Staphylococcus
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Staphylococceae family Low G + C Cocci (spheres) Grapelike clusters 3 planes 1 micrometer diameter FA Nonmotile, NSF Halotoerant Catalase (+) Oxidase (-) +/- fermentation
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Staphylococcus species 61 species Important S. aureus S. epidermidis S. saprophyticus S. pseudointermedius Others S. haemolyticus S. capitus S. hominis S. xylosis S. warneri
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Cell Wall
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Location Ubiquitous Normal flora Skin Mouth Nose Throat Predisposing factors Immunosuppression Concurrent disease AB resistance
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Epidemiology Normal microbiotica Direct transmission Portal of Entry Hair follicle Break in skin Respiratory Complications Bacteremia Septecemia Abscess
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Cytological Sample
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Pathogenesis Immune evasion Slime layer biofilm (microcapsule) Evades phagocytosis Protein A on cell wall Binds to IgG @ Fc Blocks opsonization Adhesin proteins Binds to fibrin/fibrinogen Binds to ECM laminin fibronectin collagen
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Enzymes Coagulase Catalase Hyaluronidase Lipase Beta lactamase Staphylokinase (plasminogen activator) Proteases DNase FAME (fatty acid modifying enzyme)
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Staphylococcus Toxins Cytolytic Toxins Alpha = β hemolysis Beta = sphingomyelinase Delta Gamma Leukocidin = hemolysis Leukotoxin = WBC destruction Exfoliative toxin ETA and ETB Protease & esterase activity Toxic Shock toxins Enterotoxins (A-E)
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Superantigens Enterotoxin Food poisoning, V/D TSS if B or C antigenic type TSST-1: desquamation; TSS
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Virulence Factors Summary
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Staph aureus Location Mucous membranes Moist areas Diseases Noninvasive Food poisoning Enterotoxin (V/D) Cutaneous Scalded skin Impetigo Folliculitis Boils, styes, furunculosis Systemic Soft tissue infections
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Systemic Staph. aureus infections TSS Bacteremia Endocarditis Pneumonia Meningitis Osteomyelitis Septic arthritis UTI Phlebitis
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Staphylococcal disease summary
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S. aureus Dx Isolation DDx MRSA/VRSA Tx AB based on culture Prevention Wound cleansing Hand washing
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MRSA Hosptial associated Community assoc.
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AMA/CDC poster
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VRSA vanA operon from enterococcus changes cell wall tripeptide sequence
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Opportunistic Staph pathogens S. capitis S. epidermidis S. saprophyticus S. xylosis
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S. epidermidis Location Normal skin flora opportunistic pathogen Skin/wound infections Endocarditis UTI Exposure Direct contact Newborns Elderly Fomites Catheters Shunts IV needles Prosthetics
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S. saprophyticus Pathogenesis Fimbria Adhesion proteins Autolysins Diseases UTI/cystitis Peritonitis Enopthalmitis Endocaritis Septic arthritis
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S. xylosus Commensal Industry Ferment meat Red color of sausage Ferment milk Orange color of cheese Pathogenicity Biofilms Enterotoxins Disease Nosocomial UTI Food poisoning (raw)
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S. capitis Epidemiology Skin microbiotica Head predominantly Pathogenicity Coagulase (-) AB resistance Diseases Valvular endocarditis Neonatal septicemia Osteomyelitis
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S. pseudointermedius Animal microbiotica Epidemiology Zoonotic Enterotoxins +/- coagulase Diseases Pyoderma (animals) Food poisoning
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Rapid Staph test
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Immunology Hyperimmune serum Capsular proteins Surface adhesins Vaccination At risk population ESRD Dialysis patients Premature infants StaphVAX Capsular proteins Exotoxin A (Ps. Aeurginosa)
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