Virulence GPC Flashcards
Cytolytic toxins Staph aureus
Alpha, beta, gamma, delta, and PVL
Extracellular proteins that affect RBCs and leukocytes
Hemolysins and leukocidins
PVL toxin
Panton-Valentine leukocidin
Lethal to PMNs
Suppresses phagocytosis
Most common with community acquired staph.
Staph enzymes
Coagulase
Protease
Hyaluronidase
Lipase
Coagulase virulence factor
Staph.aureus
Path. Uncertain
Hyaluronidase virulence factor
Hydrolyzes hyaluronic acid in intracellular connective tissue that permits spread of bacteria
Protein A virulence factor
Staph aureus
Binds Fc portion of IgG and block phagocytosis
SSS
Scalded skin syndrome
Caused by staph. aureus exfoliative toxin
TEN
Toxic epidermal necrolysis
Linked to Drug reactions
High mortality rate
TSST-1
Toxic shock syndrome toxin
Systemic toxin in localized S. aureus infection
High temp., Rash, vomiting/diarrhea, hypotensive
S. aureus enterotoxins A, D, B
Stap food posioning
Ingestion of toxin from contaminated food
Rapid symptoms: diarrhea, vomiting, cramps = resolve 24/48 hrs
Strep pyogenes virulence
M protein Protein F Lipoteichoic acid Streptolysin O Streptolysin S DNAse (a, b, c, d) Streptokinase Hyaluronidase erythrogenic exotoxcin
M protein
Resists phagocytosis
Adherence to mucosal cells
(Strep pyogenes)
Protein F
(GAS bacteria)
Fibronectin binding prot.
Adhesion molecule- attachment to host epithelial cells
Lipoteichoic acid
Securea attachment to oral mucosal cells w/ M protein and protein F
Hyaluronic acid capsule
S. pyogenes
Weakly immunogenic
Prevents opsonized phag.
Masks antigens
Streptolysin O
S. pyogenes
Hemolysis on sheep blood agar
Active in reduced form in anaerobic environment
Lyses leukocytes, platelets, RBCs
Highly immunogenic (used for antibody test)
Streptolysin S
S. pyogenes
Nonimminogenic
Oxygen stable
Lyses leukocytes
Streptokinase
(GAS & some grp. C & G)
Lyses fibrin clot
Hyaluronidase
Spreading factor
Enzyme that solubilizes hyaluronic acid of connective tissue
Streptococcal pyrogenic exotoxins
Cause scarlet fever
SpeA, B, C, F
Superantigens
Superantigens
Strep pyogenes
Stimulate Tcell proliferation by binding with MCH II on antigen presenting cells and beta chains on Tcell receptor
Produces IL-1, TNF, cytokines which mediate disease
SpeA
Strep pyrogenic exotoxin
Superantigen
Overstimulation of immune response
S. pneumoniae virulence factors
Capsule Hemolysin IgA protease Neuraminidase Hyaluronidase
Enterococcus virulence factors
Can grow in extreme conditions Resistant to antimicrobials Extracellular surface adhesion proteins Extracellular serine protease E. faecalis: gelatinase, toxin- 2 subunit cytolysin
