Mechanisms of Bacterial Pathogenesis
I.Entry into the body
routes
ingestion
inhalation
trauma
needlestick
arthropod bite
sexual transmission
Salmonella
Shigella
enterotoxigen E.coli
Vibrio
Clostridium botulinum
Mycobacterium
Mycoplasma pneumoniae
Clostridium tetani
Staphylococcus aureus
Pseudomonas
Rickettsia
Yersinia pestis
Neisseria gonorrhoeae
Chlamydia trachomatis
II.Adhesion,colonization and invasion
adherance
pili (fimbriae)
afimbrial adhesins
G(-)
Enterobacteriaceae
Vibrio cholerae
P fimbriae
G(+)
Streptococcus pyogenes
M protein
Biofilm
polysaccharide slime
Staphylococcus
IgA protease
colonize mucosa
III. Mechanisms of bacterial pathogenesis
Byproducts of growth
Endotoxin
Other cell wall components
Exotoxin
G(-)
G(+)
A-B toxins
Superantigen
Bacteremia
Antibiotic resistant
Immunopathogenesis
Streptococcus mutants
Mycobacteria tuberculosis
Helicobacter pylori
teeth
macrophage
stomatch
urease
LPS(lipid A)
發燒+低血壓+休克
Structure
Gene location
Simple A toxin
Simple A-B toxin
Compound A-5B toxin
Plasmid
Chromosome
Phage gene
function
enzymatic lysis
pore formation
inhibition of protein synthesis
hyperactivation
Clostridium perfringens 產氣莢膜梭菌
Staphylococcus aureus 金黃色葡萄球菌
Corynebacterium diphtheriae 白喉
Vibrio cholerae 霍亂
interfere nerve-muscle transmission
Clostridium tetani 破傷風
Clostridium botulinum 肉毒桿菌毒素
作用於肌肉
作用於神經
Apoptosis of immune cells
Over-immune response
lung
granuloma
Mycobacterium tuberculosis
heart
rheumatic fever
Streptococcus pyogenes
kidney
poststreptococcal glomerulonephritis
skin
rash
sepesis
IV.Escaping host defense
Immune Defense to Bacteria
First lines
Second lines
Prevention of epidermis
phagocytic cell responses
Complement
Cytokines and Chemokines
Antibody
Cytotoxic cells
Defense of skin
Defense of mucosal surfaces
secretory IgA
第二次感染時中和細菌
opsonization
IgG
most common antibody type
IgM
earliest appearing antibody
IgE
allergy-associated antibody
sIgA
defense of mucosal surfaces
Natural killer (NK) cells
Cytotoxic T cells
ADCC=Antibody-depedent cell-mediated cytotoxicity cells
Escaping host defense
Capsule
Resistance to antibody and complement
Evasion of phagocytic clearance
Enzymes
Formation of granuloma
Poor immunogen
Slimy
survive in phagolysosome
extent the time to spread
例子
Streptococcus pneumoniae
Neisseria miningitidis
Intracellular growth
Antigen variation
Production of IgA proteases
Production of IgG-binding protein
long O Ag of LPS
Mycobacteria
Chlamydia
Rickettsiae
Neisseria gonorrhoeae
Staphylococcus aureus
catalase
V. Pathogenic microbial flora
Strict pathogens
Opportunistic pathogens