What are exotoxins?
Gram-positive
Toxic substances released outside the cell
What are endotoxins?
Gram-negative
Toxins composed of lipids that are part of the cell membrane
What are the 3 types of Exotoxins?
A-B toxins
Membrane-disrupting toxins
Superantigens
What are the types of exotoxins differentiated by?
Structure and function
What do A-B toxins do?
B binds A active toxin
What do membrane-disrupting toxins do?
Lyse host cell by making a channel or disrupt phospholipid bilayer
What are examples of membrane-disrupting toxins that lyse host cell by making channel?
Leukocidins
Hemolysins
Streptolsin O
Clostridium
What are examples of membrane-disrupting toxins that disrupt phospholipid bilayer?
Perfringens
What do superantigens do?
Bind to T cells and cause overproduction of cytokines
Super immune response
What symptoms can superantigens cause?
Fever, nausea, vomiting, diarrhea, shock, death
What does tetanus toxin do?
Inhibits glycine
Prevents muscle relaxation
What does botulinum toxin do?
Inhibits acetylcholine
Prevents muscle contraction
What is endotoxic shock?
Life-threatening decrease in blood pressure cause by Gram - bacteria
What are cytopathic effects?
Visible effects of viral infection
What are examples of cytopathic effects?
Inhibiting of host cell macromolecule synthesis
Release of lysozymes
Inclusion bodies
Formation of syncytium
Change in host cell function
Production of interferons
Antigenic change on surface of infected cells
Chromosomal changes
Loss of contact inhibitio
What are the steps of pathogenicity?
Portal of entry
Penetration of host defenses by using capsules, cell wall components to evade WBCs or enzymes
Damage to host cells by using siderophores to steal iron, direct damage, toxins
Portal of exit