Lecture 12 Flashcards
Bacillus has what shape and stain?
GramPos (first that we have looked at)
Rods, large, fat, square ends
In chains, palisades, clumps
What is the oxygen environment for bacillus?
Aerobic (some species have pathways for butanediol of lactate fermenation)
Where is bacillus found?
Soil and leaf surfaces
Bacillus cereus is what kind of disease?
Food poisoning (not zooniosis like other bacillus)
Why is bacillus not found in a hosts blood stream?
They are spores
What are the two types of bacillus cereus?
Emetic variety-(like staph) Diarrheal variety (like c-diff)
B. cereus emetic v. presents how?
Acute N/V and cramps (1 hour)
Resolves in 1 hour
B. cerues diarrheal c. presents how?
Slower onset diarrhea and cramps (6-8 hours)
No vomiting
What foods are implicated in B. cereus infections?
Cooked pasta and rice (spores germinate and produce toxins)
What are the four toxins of B. cereus?
Emetic toxin (K+ ionophore) 3 enterotoxins: Hemolytic Non-hemolytic (forms pores) Cytotoxin (activates ad. cyc.)
What is the form of B. anthracis that is encounted?
Central spores
looks like cut glass colonies on blood agar and no hemolysis
What type of capsule does B. anthracis have?
Poly-D glutamate
What is clinical presentation of B. anthracis
Papule becomes a large necrotic eschar in 12-36 hours
Disseminates and may affect organs
How can you get anthrax?
Touching
Eating
Breathing
(usually from handling infected animal products)
How does anthrax cause illness?
Spores enter macrophages and germinate in phagolysosome upon exposure to ROS
Release a triparte AB toxin
B part binds to receptors and facilitates entry
A-lethal factor MAP kinase protease leads to necrosis
A-edema factor activates calmodulin dependent adenyl cyclase leads to water secretion
What encodes the virulence factors of anthrax
Plasmid encoded (both plasmids are needed for full virulence)
How do you treat cutaneous bacillus?
PCN
How do you treat systemic bacillus?
Doxy
Cipro
What is the vaccine for bacillus?
Live cell vaccine
PA toxoid vaccine (military)
New trial for immunoglobulin
What is shape and stain of brucella?
GramNeg
Coccobacillus
Nonmotile
What is oxygen profile for brucella?
Aerobic
Where is brucella found in it’s host?
Obligate intracellular parasites (PMNs and macrophages)
What are the four types of brucella humans can get?
B. melitensis (goats)
B. abortus (cattle)
B. suis (swine)
B. canis (dogs)
What is incubation period for brucella?
1-6 months
What is characteristic of brucella infection?
Undulant fever
Granulomas in tissues (liver, spleen, lymph nodes)
General weakness and malaise
What is a concern for how brucella can be spread by cattle?
Abortions caused by the organism can get on the grass. This can lead to infected milk.
Can also get from:
Handling infected animals
Infected labs
What tissues are commonly affected by brucella?
Endothelium granulomas of liver, spleen, bone marrow
How does brucella cause disease on a molecular level?
No exotoxin so infection from bacterial growth
How do you treat for brucella?
Doxy
Rifampin
Streptomycin
Shape and stain of francisella tularensis?
GramNeg Small coccobacillus (pleomorphic)
Describe growth of francisella tularensis?
Slow growth
Needs cysteine
Francisella tularensis clincal presentation
Inflamed, ulcerated papule at site of infection
High fever, severe toxemia
Abscess in liver, spleen, lymph node, lungs
How is francisella tularensis transmitted
Skinning infected rabbits
Ticks of deerflies
Lab hazards
What is the pathogenesis of francisella tularensis?
Complement resistant capsule
Taken up by macrophages via coiling phagocytosis
Has LPS and PG
PAI with 17 genes and T4SS mechanism
How do you treat francisella tularensis?
Doxy
Cipro
Gentamycin
Pasteurella multocida shape and stain
GramNeg
Coccobacilli
Bipolar staining which is hard to see
What is oxygen requirement for pasteurella multocida
Faculatative anaerobe
How many capsule types of pasteurella multocida have?
4
A is the most common
How does pasteurella multocida present?
Local or disseminated soft tissue abscess
Can progress to cellulitis
How do we worry about pasteurella multocida in animals?
First it’s a zoonosis
It can also kill many kinds of animals
How is pasteurella multocida often transmitted?
Almost always via animal bites
Occasionally via dust (fomites)
Pasteurella multocida pathogenesis?
Antiphagocytic capsule
Adhere with special pili and Fe-binding proteins
Adhere to macrophages but not engulfed
Pathogenesis by growth and abscess formation
Why are in vivo use of antibiotics against pasteurella multocida not very effective?
It grows very fast
How do you treat pasteurella multocida?
Pen/Amp or Ceph + tetracycline
Bartonella henselae shape and stain
GramNeg
Rods
Looks like rickettsia
Why do cats give people Bartonella henselae
Protein that can attach to feline RBCs
Where is Bartonella henselae found in humans?
Intracellular
How does Bartonella henselae present in clinic
Papule at inoculation site Local swelling Fever Regional lymph node swelling Occassionally "culture negative" endocarditis
What disease does Bartonella henselae cause
Cat scratch fever
What diease does bartonella quintana cause?
Trench fever
5 day fever, recurring
What is a third diease caused by bartonella (beside cat scratch and trench fever)?
Bacillary angiomatosis
Proliferation of small spherical blood vessels in inflamed endothelial background
Papular or tumoral lesion
Man occur in organs too
How is bartonella quintana spread?
Human lice
Common among homeless
What is bacillary angiomatosis associated with?
AIDs
What is pathogenesis of bartonella?
Outer membrane binding protein
Penetrate endothelial cells (T4SS)
Produce CSF and NF-kB and induces apoptosis
How do you treat bartonella?
Usually don’t for cat scratch fever
Azithromycin and rifampin for bacillary angiomatosis
Leptospira interrogans shape
Very thin spirochete
How do Leptospira interrogans move?
Endoflagella
What is metabolism of Leptospira interrogans
All from long chain fatty acids (no glycolysis)
How does Leptospira interrogans present?
Capillary vasculitis and edema in many organs (leakage of RBCs and serum)
Leptospira interrogans is eliminated from most places in the body with a few exceptions. What are they?
Liver, kidneys, CNS, eyes
What is the second stage of Leptospira interrogans
Weil’s disease
Jaundice due to liver failure
Nitrogen retention from kidney medulla destruction
Blood shot, oozing eyes
Meningitis
Nausea, vomiting, and intense pain from toxic organ failure
How is Leptospira interrogans transferred?
Organism can be shed into water via urine from infected kidneys
Also from infected animal urine
Leptospira interrogans pathogenesis?
No toxins detected
Intracellular growth possible
Pathogenesis from endothelial damage in capillaries
More severe in more perfused organs
Leptospira interrogans control?
Antibiotics not always useful Corticosteroids for kidney damage Macrolides and quinolones can be used Doxy used prophylactically by military when in contaminated water Vaccinate dogs against it
