Anthrax and Plague Flashcards
Describe the structure of bacillus anthracis (known as anthrax from now on). Does it have a capsule???
Large Gm (+) rods in boxcar chains
Yes, encapsulated (made of protein poly-D-glutamate, NOT polysaccharides)
Does anthrax like oxygen? Does it form spores?
Yes, it is an obligate aerobe
Yes, it forms spores
Where does anthrax exist on this vast Earth? How do we get it?
Place on Earth: soil
How we get it:
1) Cutaneous
2) Inhalation
3) GIT (infected meat ew)
Exotoxins of anthrax?
1) Lethal factor (LF)+PA: Zinc-metaloprotease that cleaves MAP kinase (controls cells growth) → tissue necrosis (black eschar)
2) Edema factor (EF)+PA: acts like adenylate cyclase that inc cAMP → fluid buildup in extracellular space → edema → prevents phagocytosis and host defenses. Calmodulin dependent.
What’s that PA shit you put on that last flashcard?
PA: protective antigen = B subunit that is the cell binding component for each of the above toxins. Anti-PA antibodies neutralize the toxin
So one of anthrax’s toxins is good enough to infect, right???
WRONG
Ya need 2 to tango (aka you must have both toxins)
So what’s so concerning about anthrax? What do you get in terms of disease of the LUNG?
Lungs: wool sorter’s disease from spores present in the wool (anthrax found naturally in soil). Sx: dry cough (cold sx → rapidly progresses to pulmonary hemorrhage→ spread to mediastinal lymph nodes → hemorrhagic mediastinitis (widened mediastinum on CXR w/ pleural effusions. No infiltrates) → 100% death
GI (rare): n/v, fever, ulcers at site of invasion (mouth, esophagus, intestine etc
Is your beautiful porcelin skin safe from anthrax?
NO IT’S NOT SAFE AT ALL
Skin (95%): papule → black eschar (painless), spread to lymph nodes
That piece of cake you just ate? Gonna stay down if you’ve ingested some anthrax?
NO IT’S NOT GONNA STAY DOWN.
GI sx (rare): nausea, VOMITING (there goes the cake), fever, ulcers at site of invasion (mouth, esophagus, intestine etc)
HOW DO WE GET RID OF THE BLACK ESCHAR/ anthrax in general
1) fluoroquinolones
2) tetracyclines (2’)
Vaccine for anthrax so we never ever ever get back together?
Biothrax:
inactivated vaccine made mostly of PA, traces of EF and LF
What does yersinia pestis look like?
Gm (-) rod
Safety pin appearance
What about some staining for yersinia?
1) Grows on McConkey agar
2) Wayson staining shows light blue bacilli with dark blue polar bodies
Vector for yersinia? General transmission?
Vector: FLEES
Transmission: occurs naturally in SW US. Cycles through rodents (mainly prairie dogs in US). Epizootics common in cool summers following wet winters. Cat transmission to humans>dogs
Describe to me, if you please, the pathogenesis of a yersinia pestis infection? Thank you, good friend.
Flee bites and regurgitates bacteria→ vesicular lesion→ phagocytosis by PMNs→ killed in PMNs or released→ can now resist further phagocytosis→ travel to lymphatics and localized to a lymph node→ bubo → stops here or disseminates leading to pneumonia, septic shock or meningitis.
