mode of transmission
mode of transmission of chlamydia trachomatis
infected secretions
contact/indirect
(trachoma - mechanical vector: flies)
mode of transmission of treponema pallidum
mom to baby (placenta)
direct contact
which gram negative pathogens are pleomorphic
chlamydia trachomatis
rickettsia rickettsii
how does actin-polymerization (also called actin-based motility) allow intracellular pathogens such as shigella and rickettsia spread from one cell to another?
allows the cell to move from cell to cell without leaving the cell and activating an immune response
What virulence facters are involved and how do the work - regarding helicobacter pylori
motility- has flagella that helps colonize in the mucous layer
urease - makes the stomach area where they're infecting less acidic
mucinase - breaks down mucous layer
cytotoxin - kills epithelial cells
Vac A toxin - damages the epithelium and interfers with lymphocyte activation
mode of transmission of borrelia burgdorferi
biological vector (deer ticks)
mode of transmission of campylobacter jejuni
foodborne
what virulence factor do all gram negative pathogens have and what does it do
lipid A
causes shock, DIC, fever, vasodialation, inflammation
what class of e.coli is the most dangerous and why?
Enterohemorrhagic e.coli (EHEC) because it produces a shiga-like toxin - causing hemolytic uremic syndrome
why are anti-diarrheal medications and antibiotics often contraindicated when treating EHEC infection
because they increases the risk of hemolytic uremic syndrome and makes sx worse
mode of transmission of rickettsia ricketsii
biological vector
mode of transmission of helicobacter pylori
ingestion
how does the shiga toxin cause bloody diarrhea and uremic syndrome
uremic syndrome - shiga like toxin causes RBCs to fragment, these fragments clog the glomeruli and impair filtration
bloody diarrhea - attaches to the epithelial cell of colon. shigella triggers phagocytosis. shigella multiplies in cytosol. shigells invades neighboring cells, avoiding immune system. an abscess forms as epithelial cells are killed by the infection. shigellsa enters the blood is quickly phagocytized
which gram negative pathogens are spirals
borrelia burgdorferi
treponema pallidum
what do these extracellular enzymes do in pathogenesis: igA protease, hyaluronidase, coagulase, lipase, DNAse
igA protease: breaks down IgA antibodies
hyaluronidase: breaks down hyaluronic acid
coagulase: causes cell to clot and allows bacteria to hide inside host cells and reproduce inside the clot until broken by kinase
lipase: helps bacteria spread through tissues
DNAse: breaks down host DNA
mode of transmission of vibrio cholerae
waterborne
foodborne
(swimming, or touching water, ingestion of contaminated water)
N. gonorrhoeae
N. meningitidis
what two toxins does pertussis use/produce and what do they do
pertussis toxin: increases mucous production, inhibits lymphocyte migration (impairs immune response)
tracheal cytotoxin: paralyzes cilia, damages and destroys ciliated cells
what organism causes stomach ulcers?
Helicobacter pylori
what is the mechanisms of the cholera toxin
cholera toxin binds to membrane of epithelial cell
protion of toxin enters cell
A1 stimulates adenylate cylase (AC)
cyclic AMP (cAMP) is synthesized
cyclic AMP stimulates cell to secrete Cl- and Na+ and other electrolytes
water follows electrolytes into intestinal lumen
causing the severe dehydration
mode of transmission of vibrio vulnificus
foodborne - consumption of contaminated shellfish (septicemia)
direct/indirect? - wounds contaminated with seawater (necrotizing fascitis)
which gram negative pathogens are rods
e.coli
p.vulgaris/mirabilis
shigella
s.enteritidis (typhoid & non typhoid)
yersinia pestis
b. pertussis
legionella pneumophilia
p.aeruginosa
which gram negative pathogens are curved rods
vibrio cholerae
vibrio vulnificus
campylobacter jejuni
h.pylori (helix shaped)
what is unique about the cell wall of chlamydia and rickettssia rickettsii and how does it affect what antibiotics are given
chlamydia - no peptidoglycan
r.rickettsii - thin peptidoglycan
penicillins will not work on these because of the peptidoglycan
what is the oxygen class of h.pylori
microaerophile