Pyogenic Microorganisms Roy, Nova, Jessie, Szechia, and Shangyoung
Pyogenic Microorganisms Roy, Nova, Jessie, Szechia, and Shangyoung
Contents Pyogenic Infections Virulence factors Pathogenesis Immuno-resistance
Contents • Pyogenic Infections – Virulence Factors – Pathogenesis • Immuno-resistance
Serious Pyogenic Infections Bacteremia- The presence of bacteria in blood Septicemia -a bacteremic condition that leads to Sepsis Pyemia-a Septicemic condition that leads to widespread abcesses of metastatic nature
Serious Pyogenic Infections • Bacteremia – The presence of bacteria in blood • Septicemia – a bacteremic condition that leads to Sepsis • Pyemia – a Septicemic condition that leads to widespread abcesses of metastatic nature
S. Aureus virulence Factors Enzymes: Coagulase, Hyaluronidase and dnase Protein A: binds to Fc-lgG to inhibit complemen fixation and phagocytosis Toxins 1. Superantigens: TSST-1 that produce toxic shock syndrome, enterotoxins that cause gastroenteritis 2. Exfoliative toxins: protease activity cases peeling of skin in staphylococcal scalded-skin syndrome 3. Other toxins: alpha, beta, and delta toxins act on cell membane and Panton -Valentine leukocidin (PVL) is associated with severe necrotizing pneumonia in children
S. Aureus Virulence Factors • Enzymes: Coagulase, Hyaluronidase, and DNAse • Protein A: binds to Fc-IgG to inhibit complement fixation and phagocytosis • Toxins: 1. Superantigens: TSST-1 that produce toxic shock syndrome, enterotoxins that cause gastroenteritis 2. Exfoliative toxins: protease activity cases peeling of skin in staphylococcal scalded-skin syndrome 3. Other toxins: alpha, beta, and delta toxins act on cell membanes, and Panton-Valentine leukocidin (PVL) is associated with severe necrotizing pneumonia in children
S. Aureus Pathogenesis Combined effect of extracellular factors and toxins together with invasive properties of the strain More dangerous strains of s Aureus causes focal abscess that can spread via lymphatics or blood Can result in meningitis, endocarditis and sepsis Can also causes disease through toxins: SSss and Tss
S. Aureus Pathogenesis • Combined effect of extracellular factors and toxins together with invasive properties of the strain • More dangerous strains of S.Aureus causes focal abscess that can spread via lymphatics or blood. • Can result in meningitis, endocarditis, and sepsis • Can also causes disease through toxins: SSSS and TSS