Toxigenic Bacteria Flashcards
when are exotoxins produced?
During exponential growth phase (log phase)
What bacteria can produce exotoxins?
Both gram + and gram -
Define exotoxin
Exotoxin are diffusible proteins with enzymatic activities.
it blocks protein synthesis which causes cell death.
Where do exotoxins act?
Distally or locally at infection site and can function as invasins
what are the three basic types of exotoxins
A-B Type
Membrane disrupting
Superantigens
what is the function of a capsule?
protection against phagocytosis
what are the three forms of anthrax?
cutaneous (spread by insect bites or anthrax spores entering cut)
inhalation (anthrax spores in air)
gastrointestinal (infected meat)
what is the causative organism for Bacillus anthracis (anthrax)?
Large gram + aerobic rod with square ends
Encapsulated (cannot be phagocytosed)
It is an A2B Toxin
centrally located spores on nutritional depletion
what are Bacillus anthracis virulence factors?
poly-gamma-D-glutamate capsule -genes carried on pxO2
A2B Toxin - genes carried on pXO1
Spore formation
How to diagnose anthrax?
Gram stain for gram +
nasal swab only determines exposure
how to treat anthrax?
Antibiotics but mainly used for cutaneous
Monoclonal antibodies approved for inhalatioin anthrax
describe features of corynebacterium diphtheriae
gram + bacillus clubbed ends and palisading
aerobic
thick grey mucoid coat
colonizes throat and nasopharynx
describe diptheira toxin
low iron = high tox expression
ADP-ribosylates elongation factor 2 (EF-2)
Simple A-B toxin
binds to HB-EGF receptor
How do you treat bordetella pertussis?
antibiotics- blocks the spread
adequate oxygen support
what can cause dysbiosis?
an environmental trigger