(SOME) Zoonoses Flashcards
Describe the physical structure of Bacillus.
G+ Rods
Large, Fat, Square Ends
Chains, Palisades, Clumps
Bacillus response to adversity?
Sporulation
Oxygen metabolism of Bacillus.
Aerobic
Some species have butanediol or lactate ferm pathways.
Where can Bacillus be found primarily?
Soil and on Leaf Surfaces
Two types of Bacillus we covered?
Bacillus cereus
Bacillus anthracis
Bacillus cereus is typically seen in what context?
Food Poisoning
Describe the physical appearance of Bacillus cereus spores.
Subterminal
Describe the physical appearance of Bacillus cereus colonies on agar plates.
Large, flat, rough
What two varieties of Bacillus cereus are seen clinically?
Emetic Variety
Diarrheal Variety
Describe the clinical presentation of emetic variety Bacillus cereus.
Very Acute Onset (1-6 hrs)
Recovery in 12 hours
Nausea, Vomiting, Cramps
Describe the clinical presentation of the diarrheal variety of Bacillus cereus.
Slow onset (8-16 hrs)
Profuse Diarrhea, Cramps
No Vomiting
How do people get Bacillus cereus?
Cooked rice and pasta that has been cooled too slowly?
Why the fuck does it matter how slowly my rice cools?
Cooling slowly allows spores to germinate and produce the toxin
How many toxins are associated with Bacillus cereus?
4 (1 emetic toxin and three enterotoxins)
What does the emetic toxin of Bacillus cereus do?
K+ Ionophore
What are the three enterotoxins associated with Bacillus cereus?
Hemolytic
Non-hemolytic (pore-formers)
Cytotoxin (Activates Ad cyclase)
Unique physical characteristics of Bacillus anthracis?
Central Spores
“Cut glass” colonies on blood agar
Poly-D-glutamate capsule
Clinical presentation of Bacillus anthracis?
Papule (12-36 hrs) becomes a large necrotic eschar
Disseminates and becomes systemic
May infect any organ
What is an eschar?
a dry, dark scab or falling away of dead skin
Three most common causes of diarrhea (not necessarily in order)
Norovirus
S Aureus
B cereus
How is Bacillus anthracis typically contracted?
- Animals ingest/carry spores from soil
- Human handles infected animal materials
- Spore contacts mucous membranes or enter through abrasions
- Germinate in Macrophages after engulfment
How long are Bacillus anthracis spores viable?
more than 50 years
Four ways (even though they may kind of overlap..) that Bacillus anthracis can get into the body
Contact Mucus Membrane
Abrasion
Inhalation
Ingestion
Why should we give a shit about Bacillus anthracis if it comes up less than once a year in the whole world?
Possibly comes up in bioweaponization
What do spores do upon entering the host?
Enter macrophages
Germinate in the phagolysosome (upon O2 radical exposure)
Can Bacillus anthracis spores be found in blood smears?
No
Describe the Bacillus anthracis toxin
Tripartite AB-type (A2B) toxin
What are the three components of Bacillus anthracis toxin?
Binding (Protective Antigen)
Lethal Factor
Edema Factor
What does Bacillus anthracis Lethal Factor do?
It is a MAP Kinase Protease responsible for necrosis
What does Bacillus anthracis Edema factor do?
It is a calmodulin-dependent adenyl cyclase
It makes cAMP, which causes H2O secretion into tissues
Both virulence factors of Bacillus anthracis (______, ________) are encoded by ______.
(Toxin, Capsule)
Plasmid Encoded
How do you treat Bacillus anthracis?
Penicillin (cutaneous), Doxycycline, Ciprofloxacin
How is Bacillus anthracis controlled?
Live pXO2 vaccine
PA toxoid vaccine (military)
Livestock vaccine
Describe the physical structure of Brucella
G-
Aerobic Coccobacillus
T or F. Brucella is dangerous due to its rapid growth rate.
F. Very Slow growing (5 days on plate)
Growth site of Brucella in host?
Facultative Intracellular parasite
Four species of Brucella that affect humans?
Brucella melitensis (goats) Brucella abortus (cattle) Brucella suis (swine) Brucella canis (dogs)
In what animal population is Brucella becoming more common?
Dogs – spreading through animal shelters
Up to 10% prevalence in kennels
Clinical presentation of Brucella?
1-6 week incubation Undulant Fever May become chronic -- weakness Granulomas (Liver, Spleen, LN, bone) Psychoneuroses
What is an Undulant Fever?
Fever that goes up and down on a regular basis
rise in afternoon, drop w/ profuse sweating in evening
How may Brucella present in livestock (esp cattle)?
Bacteria bind erythritol in testes, placenta, or mammary tissue
If on placenta, form foci that detach microvilli
Abortion Storm
What is an abortion storm?
Large scale abortions throughout an animal population
How is Brucella in cattle so common out West?
Wild animals (Bison, goats, elk, sheep) carry it
Male transmits in semen
Abortion storm contaminates pasture grass
How do humans acquire Brucella?
Infected milk
Handling Infected Animal
Lab Accident
How is Brucella diagnosed?
Blood Sample
Serology
Culture
Pathogenesis of Brucella?
Intracellular survival in PMNs/Macrophages
Spreads to lymphatics and bloodstream
Infects liver, spleen, BM – Forms granulomas
Bacterial growth – Inflamm. response
So…what actually causes the undulant fever?
Bacterial release from macrophages
Brought back down as it is taken back in by macrophages
How can Brucella be controlled?
Pasteurize Milk
Eradicate from herds/Segregate from wild herds
Testing/Slaughter of Infected Animals
Human Live Vaccine in Russia
Why don’t Americans vaccinate for Brucella?
We don’t want to deal with the whole LPS toxicity thing.
U-S-A, U-S-A, U-S-A
How is Brucella treated?
Doxycycline + Rifampin +/- Streptomycin
Why might treatment tend to be ineffective?
Intracellular pathogen
If you see an elevated erythrocyte sedimentation rate and C-Reactive Protein, what should you suspect?
Inflammation is happening
Describe the structure of Francisella tularensis?
Small G- Coccobacillus
Pleomorphic
Slow Growth
Francisella tularensis have a fastidious requirement of…
Cysteine
Clinical Presentation of Francisella tularensis?
2-6 days Incubation
Inflamed, Ulcerated Papule at Infection Site
High Fever, Severe Toxemia
Abscess Formation in Liver, Spleen, LN, Lungs
Francisella tularensis is commonly found on what part of the body?
Hands (from skinning animals)
Reservoirs for Francisella tularensis?
Type A – Rabbits (Most Severe)
Type B – Beaver/Rodents (Milder)
Area of the country that looks like its got Francisella tularensis all over it?
Missouri, Arkansis, Oklahoma
Three methods of human acquisition of Francisella tularensis?
Skinning Infected Animals (and aerosol inhalation of carcass)
Ticks/Deerflies (maybe other biters)
Laboratory Hazards (Ingestion, Inhalation)
How infection is Francisella tularensis?
Infectious dose = 10 bacteria
Need P3 containment lab to grow it
Pathogenesis of Francisella tularensis?
Capsule resists complement
Take up by mphages by coiling phago.
Prevents oxidative burst, grows intracellularly
T4SS + effectors that prevent phagolyso fusion
LPS and PG release
How is Francisella tularensis treated?
Doxycycline, Cipro, gentamycin
Ways of controlling Francisella tularensis spread?
Strict isolation of lab organisms
Care while skinning rabbits
live cel vaccine for military
Francisella tularensis has a PAI with 17 genes. What is a PAI?
Pathogenic Island in the genome that contains genes that mediate pathogenicity
Describe the structure of Pasteurella multocida?
Small G- coccobacilli
Bipolar Staining
Oxygen requirements of Pasteurella multocida?
Facultative Anerobe
How many capsular antigen types of Pasteurella multocida are there?
4
Clinical presentation of Pasteurella multocida in humans?
Local or disseminated edematous soft tissue abscess
Occurs within a few hours of animal bite
Rapidly progressive cellulitis
You see proximal streaking along a lymph tract
Significance of Pasteurella multocida in the animal kingdom?
Fowl cholera (pneumonia) – wipes out flocks
Shipping Fever (cattle) – Copious nasal discharge,
septicemia, acute pneumonia, death
Snuffles (rabbits) – progress to lethal hemorrhagic pneumonia
How does Pasteurella multocida typically spread to humans?
Animal bites (Carried by 90% cats and 70% of dogs) Sometimes fomites (dust -- chicken shed workers)
Pathogenesis of Pasteurella multocida?
Antiphagocytic Capsule
Pili, Adhesion Proteins, Fe-binders
Adhere to mphage, but not engulfed
Growth and abscess formation
What is unique about the growth of Pasteurella multocida?
in vivo is as fast as in vitro
Grows too fast for immune system to keep up very well.
Is Pasteurella multocida very susceptible to antibiotics? Why?
No – Grows too fast
How is Pasteurella multocida treated?
Multiple Drugs
Pen/Amp or Ceph + Tetra
Remember, most animal bites are….
Polymicrobial
Describe the physical structure of Bartonella henselae.
Gram negative small rod
Difference between Bartonella henselae and Rickettsia?
Bartonella henselae can grow on Lab Media
What does Bartonella henselae attach to in cats? humans?
Cats – RBCs
Humans – Endothelial Cells (Intracellular)
Describe the clinical presentation of Bartonella henselae.
Cat Scratch disease
Papule at inoculation site, local swelling, fever
Regional Lymph Node Involvement
Occasionally “Culture Negative” Endocarditis
Describe the clinical presentation of Bartonella quintana.
Trench Fever/Homeless Fever
5 day recurring fever
Headache, lymphadenopathy
What is Bacillary angiomatosis?
Proliferation of small spherical blood vessels in an inflamed endothelial background (blood vessel tumor)
May occur as papular/tumoral lesion or in organs
What bacterium cause Bacillary angiomatosis?
Bartonella henselae
Bartonella quintana
Bartonella bacilliformis
Who is more likely to get Bacillary angiomatosis?
Immunocompromised/AIDS patients
What causes Bartonella henselae.
Cat Scratches or Bites #1 Cause of localized lymph node swelling in children
How is Bartonella quintana is spread by…
..human head and body lice.
Describe Bartonella pathogenesis.
Outer Membrane Binding Protein
T4SS + Effector Protein
Produces Cell-Stimulating Factor
What does Effector Protein do?
Ruffling of the membrane to promote endocytosis
Stops Phag-lys fusion
What does Cell-stimulating factor do?
Stimulating NF-kB and induces apoptotic pathways
How would you typically treat Cat Scratch disease?
You wouldn’t
What can you use to treat Bartonella?
Azithromycin +/- Rifampin
Elevated Liver enzymes are typically indicators of what two things.
1) Liver Involvement
2) Muscle Breakdown/Rhabdomyolysis
What would you expect to see change in a CBC if you have cellulitis and nothing else.
No major CBC changes.
Two common polymicrobial infections.
Animal Bites
Abscess
Why do you take Ab levels early in an infection?
As a baseline
Describe the structure of Leptospira interrogans.
Exceedingly this spirochete
Seen on SEM
Endoflagella
Describe the difficulty in growing Leptospira interrogans.
Pretty easy for a spirochete – 6 days to visible col.
How do Leptospira interrogans get energy.
Long-chain F.A.
No glycolysis
Clinical presentation of Leptospira interrogans initial stage.
Fever from bacteremia
Capillary Vasculitis and edema
leakage of RBCS and Serum (Petechiae, Bleeding)
Bac eliminated everywhere but liver, kidneys, CNS, eyes
Clinical presentation on Leptospira interrogans secondary
Weil's Disease - Jaundice from liver failure - Nitrogen retention in Kidney Medulla Destruction Bloodshoot, Ooozing Eyes Meningitis
How is Leptospira interrogans typically contracted?
Shed into water from infected kidneys
Persists in fresh water and is ingested
Also spread in rat and dog urine
Describe the pathogensis of Leptospira interrogans.
Intracellular growth possible
Pathogenesis from endothelial damage in capillaries
– Highly perfused organs more affected (liver, kidneys)
How is Leptospira interrogans treated?
Antibiotics are of limited control
Macrolides or Quinolones can be used
How is Leptospira interrogans controlled?
Prophylactic Doxycycline by the military
Avoid rat-contaminated water
Vaccinate dogs
What does ANP indicate
Heart Damage (should be under 100)
Treatment for cellulitis.
Clindamycin, Keflex
Penicillin for likely MRSA coinfection
