Bacterial zoonoses I Flashcards
What is the gram stain for bacillus anthracis?
Gram positive
What is the shape of bacillus anthracis?
Rod
Is bacillus anthracis aerobic or anaerobic?
Aerobic
Does bacillus anthracis form spore?
Yes
What is the appearance of bacillus anthracis in culture?
Long chains / pairs / single cells with “boxcar” ends
If you collect a sample from a patient with bacillus anthracis, will you see spores?
Probably not
What is the main virulence factor for bacillus anthracis?
Protein capsule made of poly-D-glutamate
What are the two toxins produced by bacillus anthracis?
Lethal toxin and edema toxin
What is the role of lethal toxin?
Disrupts normal cellular signaling events leading to cell death, inflammation, and tissue damage
What is the role of edema toxin?
Activates adenylate cyclase, leading to increased cAMP levels, ion/water efflux, and edema
What is the role of protective antigen in bacillus anthracis infection?
- Acts like the B subunit of an A-B toxin; binds lethal and edema factors to form toxins then facilitates internalization of toxins 2. Binds to each factor to form the toxins
What is the pathogenesis of bacillus anthracis?
- Spores are inoculated, ingested, or inhaled 2. Spores germinate into vegetative cells that produce toxin
What are the features of a lesion caused by cutaneous anthrax?
Small red painless papule that evolves into an vesicle then a necrotic ulcer with black center (eschar)
What are the symptoms of (second stage) inhalation anthrax?
Fever, drenching sweats, extreme dyspnea, cyanosis, lymphadenopathy, shock, death
What is the treatment for cutaneous anthrax?
Amoxicillin
What is the treatment for inhalation anthrax?
Doxycycline, ciprofloxacin + 2 other Abx
What is the gram stain for brucella?
Gram negative
What is the shape of brucella?
Coccobacillus
What is the pathogenesis of brucella?
Intracellular pathogens - survive within phagosomes of macrophages and monocytes
What is the transmission for brucellosis?
Aerosol or ingestion - contaminated food (unpasteurized milk), direct contamination with infected animal
What is the presentation for brucellosis?
Acute undulating fever, joint pain, headache, drenching sweats
What is the treatment for brucellosis?
6 week or longer course of a tetracycline (doxycycline) + rifampin
What is the gram stain for pasteurella multocida?
Gram negative
What is the shape of pasteurella multocida?
Coccobacillus
What are the virulence factors for pasteurella multocida?
LPS and polysacccharide capsule (hyaluronic acid)
In the US, how do pasteurellosis infections usually occur?
Following scratch or bite of a cat or dog
What is the treatment for pasteurellosis?
Penicillin
What is the gram stain for leptospira?
Gram negative (weakly)
What is the shape of leptospira?
Spiral shaped with terminal hooks
How is leptospira best visualized?
Darkfield
What is the pathogenesis of leptospirosis?
Infects via cuts and mucous membrane exposure from contaminated water
What are the two phases of leptospirosis?
- Febrile, influenza-like 2. Disseminated
What is the treatment for leptospirosis?
Penicillin and ampicillin
What is the gram stain for francisella tularensis?
Gram negative
What is the shape of francisella tularensis?
Coccobacillus
What is the pathogenesis of francisell tularensis?
Intracellular pathogen of monocytes and macrophages - prevents phagolysosome fusion and acidification
What is crucial for resolution of tularemia infection?
CMI (macrophage activation)
What are the virulence factors for francisella tularensis?
Intracellular pathogen, polysaccharide capsule (strongest), LPS
What is the vector for francisella tularensis?
Hard-shell ticks
What are the three major forms of tularemia?
Skin, eye, lungs
Patients with ulceroglandular tularemia will present with which symptoms?
Red, swollen, painful, ulcerative papule and photophobia
What is the treatment for tularemia?
Gentamicin
What is the gram stain for yersinia pestis?
Gram negative
What is the shape of yersinia pestis?
Rod with bipolar Giemsa staining (“safety pin”)
What stain is used for yersinia pestis?
Giemsa
What are the yersinia pestis virulence factors?
Protein capsule, LPS, three plasmids
The plasmids associated with yersinia pestis virulence carry what three major genes?
Biofilm formation, enhanced resistance to macrophage killing, resistance to complement mediated lysis
What is the treatment for bubonic plague?
Streptomycin
