Staphylococcus

Staphylococceae family Low G + C Cocci (spheres) Grapelike clusters  3 planes  1 micrometer diameter FA Nonmotile, NSF Halotoerant Catalase (+) Oxidase (-) +/- fermentation

Staphylococcus species 61 species Important  S. aureus  S. epidermidis  S. saprophyticus  S. pseudointermedius Others  S. haemolyticus  S. capitus  S. hominis  S. xylosis  S. warneri

Cell Wall

Location Ubiquitous Normal flora  Skin  Mouth  Nose  Throat Predisposing factors  Immunosuppression  Concurrent disease  AB resistance

Epidemiology Normal microbiotica Direct transmission Portal of Entry  Hair follicle  Break in skin  Respiratory Complications  Bacteremia  Septecemia  Abscess

Cytological Sample

Pathogenesis Immune evasion  Slime layer biofilm (microcapsule) Evades phagocytosis  Protein A on cell wall Binds to Fc Blocks opsonization Adhesin proteins  Binds to fibrin/fibrinogen  Binds to ECM laminin fibronectin collagen

Enzymes  Coagulase  Catalase  Hyaluronidase  Lipase  Beta lactamase  Staphylokinase (plasminogen activator)  Proteases  DNase  FAME (fatty acid modifying enzyme)

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)

Superantigens Enterotoxin  Food poisoning, V/D  TSS if B or C antigenic type TSST-1: desquamation; TSS

Virulence Factors Summary

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

Systemic Staph. aureus infections TSS Bacteremia Endocarditis Pneumonia Meningitis Osteomyelitis Septic arthritis UTI Phlebitis

Staphylococcal disease summary

S. aureus Dx  Isolation  DDx MRSA/VRSA Tx  AB based on culture Prevention  Wound cleansing  Hand washing

MRSA Hosptial associated Community assoc.

AMA/CDC poster

VRSA vanA operon from enterococcus changes cell wall tripeptide sequence

Opportunistic Staph pathogens S. capitis S. epidermidis S. saprophyticus S. xylosis

S. epidermidis Location  Normal skin flora  opportunistic pathogen Skin/wound infections Endocarditis UTI Exposure  Direct contact Newborns Elderly  Fomites Catheters Shunts IV needles Prosthetics

S. saprophyticus Pathogenesis  Fimbria  Adhesion proteins  Autolysins Diseases  UTI/cystitis  Peritonitis  Enopthalmitis  Endocaritis  Septic arthritis

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)

S. capitis Epidemiology  Skin microbiotica  Head predominantly Pathogenicity  Coagulase (-)  AB resistance Diseases  Valvular endocarditis  Neonatal septicemia  Osteomyelitis

S. pseudointermedius Animal microbiotica Epidemiology  Zoonotic  Enterotoxins  +/- coagulase Diseases  Pyoderma (animals)  Food poisoning

Rapid Staph test

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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