Bacterial Zoonotic & Uncommon Pathogens Flashcards
Brucella
Brucellosis
Manifestations:
- -*Undulant Fever
- -*Weight Loss
- -Night Sweats
Enlargement of Reticuloendothelial organs:
- -*Splenomegaly
- -Liver
- -Lymph nodes
Diagnosis:
- -Blood Culture or
- -Bone Marrow Biopsy
- -Serological test
Epidemiology:
–*Occupational Exposure:
(Farmers, Vets, etc.): Inhalation, Skin, Mucous membranes
–Ingestion of *Unpasteurized Dairy Products
–California, Texas (states near Mexico)
Treatment:
–Doxycycline + Aminoglycoside (Streptomycin or Gentamycin)
Immunity:
–Controlled by **T-cell Mediated Cellular immune responses
Prevention:
- -**Minimize Occupational exposure and
- -**Pasteurize Dairy Products
Pathogenesis:
- -Multiplies in Liver, Spleen, Bone Marrow, etc.
- -Eventually forming **Granuloma
–Progresses with the formation of small granuloma and with **Release of Bacteria Back into the Systemic Circulation
==> Fever!
Morphology:
- -Gram Negative Coccobacilli
- -Non-motile
- -Non-encapsulated
- -Non-sporing
Yersinia pestis
Plague
Manifestations:
–**Bubo: painful, swollen lymph node, usually @ Groin or @ Axilla. (Hemorrhagic suppurative lymphadenitis)
–Pneumonic Plague: necrotizing hemorrhagic pneumonia
–Cyanosis = Black Death
Symptoms:
–Fever, Malaise, Productive Cough, Dyspnea
Epidemiology: --Host: Rats, Prairie Dogs --Vector: Fleas --**Western States: Mexican Border to eastern half of Washington state: Arizona, New Mexico, Colorado, Utah
Diagnosis:
- -**Gram Stain from Bubo
- -Immunofluorescence
- -**Avoid delay in diagnosis.
Treatment:
- -**Streptomycin or
- -**Gentamycin
Immunity and Prevention:
- -**Antibody against F1 Protein (may be protective?)
- -**Rat control
- -**Insecticides
- -Chemoprophylaxis with Doxycycline and Ciprofloxacin
Pathogenesis:
1) **Multiplies within Flea @ Ambient temp *25 C.
2) Flea bites human, releasing Yersinia into wound
3) **@ 37 C in body temp:
- -Yersinia develops **F1 Anti-Phagocytic Capsule
- -And secretes **Yops into Host cells and Extracellular membrane.
- *Yops:
- -Yersinia Outer membrane proteins
- -**Disrupt signaling pathways and Destroy Cytoskeleton structure.
Morphology:
- -Gram Negative
- -Coccobacillus
- -Non-motile
- -Non-sporing
Francisella Tularensis
Tularemia
Manifestations: 1) **Ulceroglandular Form: Papule --> Ulcer 2) **Oculoglandular Form: Painful Purulent Conjunctivitis 3) **Typhoidal Tularemia: Abdominal manifestations 4) **Pneumonic Tularemia
Symptoms:
- -**Loss of Appetite
- -Inflammation spreads to **Lymph Nodes, which may enlarge and may suppurate (Mimicking Bubonic Plague)
- -Fever
- -Lethargy
- -Septicemia
- -Inflamed, Reddened Face and Eyes
- -Possibly Death
Epidemiology: --**Tick Bite or Direct Contact with **Minor Skin Abrasion --Inhalation during **Lawn Mowing --**Skinning Rabbit --**Lower Midwestern States (Arkansas, Missouri, Oklahoma)
Diagnosis:
- -**Culture: Enriched **Cysteine heart agar **Blood Culture Medium.
- -**Serologic test
Treatment:
- -**Streptomycin
- -Gentamycin
Pathogenesis:
–Forms **Granulomas @ Reticuloendothelial organs
Immunity:
–T-cell mediated (CD4+ and CD8+)
Prevention:
- -Rubber gloves, eye protection
- -Remove ticks
Morphology:
- -Gram Negative
- -Coccobacillus
- -Non-motile
- -Pleomorphic
Other names:
- -Pahvant valley plague
- -Rabbit fever
- -Deer fly fever
- -Ohara’s fever
Corynebacterium Diphtheriae
Diphtheria
Manifestations:
1) **Pharyngitis or **Tonsilitis:
(After 2-4 day Incubation period)
(DT-A) Gray-white **Pseudomembrane @ mucous membrane
(contains PMNs and dying, infected cells)
–Infection gradually resolves in uncomplicated case, and membrane is coughed up after 5-10 days
–Pseudomembrane, Edema, and Hemorrhage can produce *Respiratory Obstruction, leading to Suffocation
2) (DT-B)**Cervical Adenitis (common)
* *“Bull Neck” in severe case.
3) **Diphtheritic Myocarditis:
= **Inflammation of Myocardium (most common complication, 2/3 pts, and most serious)
–Cardiac Enlargement
–Arrhythmia
–Congestive Heart Failure
–Dyspnea
**Absorbed Dip Toxin into the Circulation
4) **Cutaneous Diphtheria (DT-A):
- -Simple Pustule
- -Progresses to Chronic Non-Healing Ulcer in skin
5) **Reversible Paralysis:
- -Soft Palate,
- -Oculomotor Muscles (DT-B),
- -Diaphragm, etc.
Epidemiology:
- -**Transmission: Respiratory droplet
- -Absorption of Toxin across pharyngeal mucosa
- -Circulation of toxin in blood
- -DT binds throughout body, leading to **Necrosis and **Inflammation.
Diagnosis: --**Primary: **Clinical --Isolation: **Non-Hemolytic, Selective Medium: **Potassium Tellurite Gram Stain: **"Club" Shape (Chinese letter or palisade arrangement)
Treatment:
–Diphtheria Anti-Toxin:
Not licensed by FDA for use in USA.
–Erythromycin: most effective
Prevention:
–**Diphtheria-Pertussis-Tetanus (DPT) Vaccine
*Inactivates B subunit.
Booster shot every 10 years
Pathogenesis:
–Diphtheria Toxin (DT):
Consists of A and B subunits
–B Subunit: Binds to the EGF Receptor in humans.
(EGF signaling: cell proliferation, inhibition of apoptosis, angiogenesis, etc.)
–A Subunit: Inhibits Protein Synthesis in all Eukaryotic cells
(Via inactivating the Elongation Factor by ADP-ribosylation, thereby inhibits transfer of tRNA and protein synthesis irreversibly)
Morphology:
- -Gram Positive Rods
- -**Catalase Positive
- -Aerobe
- -Non-sporing
- -Non-motile
- -Pleomorphic, Small
Listeria monocytogenes
Listerosis
Can grow at temp as *Low as 1 C (refrigerator-resistant)
Manifestations:
1) **GI Infection (primary):
- -Nausea + Abdominal Pain
2) **Listeria Meningitis:
–Has Tropism for CNS, including Brain Parenchyma (Encephalitis) and Brainstem
(Ventriculomegaly, Sulcal Effacement on CT = brain swelling and increased ventricular size)
–High Mortality Rate
3) **Placental Infection:
- -Intrauterine infections leads to **Stillbirth or **Disseminated infection @/near Birth.
Epidemiology:
- -**Food-Borne Transmission
- -*Transplacentally or in *Birth Canal
- -Biofilms make surfaces difficult to decontaminate
- -*Listeria can grow in Refrigerator!
Diagnosis:
- -Culture: Blood, CSF, or Focal lesion
- -**Beta-hemolytic (yellow)
Treatment:
- -**Ampicillin
- -**Penicillin G
- -Trimethoprim/ Sulfamethoxazole (TMP/SMX)
Prevention:
–Avoid Unpasteurized Dairy
At-Risk Pops:
- -Pregnant women
- -Elderly
- -Immunosuppressive therapy
- -AIDS
Immunity: T cell-mediated
Pathogenesis:
1) Internalin: surface protein; attaches to Host cell Receptor
(E-cadherin)
2) LLO (Listeriolysin O) (a cytotoxin) and Phospholipases allow escape from Phagosome to Cytosol
3) Disruption of metabolism of cell’s actin and microtubule infrastructure
4) Cell-to-cell spread by moving along fibers by polymerizing Actin
(Actin Comet Tail)
(Cell-to-cell spread avoids exposure to immune system)
Morphology:
- -Gram Positive Rods
- -Non-Sporing
- -**Beta-Hemolytic
- -**Catalase Positive (unlike streptococci)
- -Motile (tumbling) (unlike corynebacteria)
Bacillus Anthracis
Anthrax
Manifestations:
1) Cutaneous Anthrax: Spores exposed to body
- -Erythematous Papule @ 2-5 days
- -Black Eschar (Scab) + Edema surrounds @ 7-10 days
2) Pulmonary Anthrax: Inhalation of Spores
- -1-5 days of non-specific Malaise, Mild Fever, Non-productive Cough
- -Progressive Respiratory Distress + **Cyanosis
- -Rapidly **Fatal
- -Widened Mediastinum on X-ray
3) **Intestinal Anthrax:
- -Food Contamination, usually Meat.
Epidemiology:
- -Infection with **Spores (percutaneous, inhaled, ingestion)
- -Widespread in air, soil, water, dust, animal products, esp. herbivores (horses, sheep, cattle)
Diagnosis:
–Culture Skin lesions, Blood, CSF, sputum
Treatment:
- -**Little Effect of antimicrobial treatment on course of Cutaneous anthrax.
- -**Ciprofloxacin or **Doxycycline for treatment and prophylaxis.
Prevention:
- -**Vaccines (live and inactivated)
- -**Autoclaving animal products.
Pathogenesis:
- -**Exotoxin Complex:
1) Protective Antigen (PA) delivers Edema Factor (EF)/ Lethal factor (LF) to the Capillary Morphogenesis protein-2 (CMP-2) on cell membrane of target macrophage, where exotoxin complex is transported to an Endosome.
2) Exotoxin complex is delivered from endosome into cytoplasm, where it exerts its toxic effects.
3) Anti-Phagocytic properties of D-glutamic acid capsule aid in survival.
Morphology:
- -Gram Positive Rods
- -**Spores!!
- -Catalase Positive!!
- -Aerobes
- -Non-motile
- -Enapsulated
Bacillus Cereus
Manifestations: 1) Infections @ Eye, Lung, Soft tissues 2) **Food Poisoning via **Emetogenic Enterotoxin (Vomiting) (Fried Rice) (is a heat-stable toxin) (enterotoxin similar to S. aureus)
3) **Pyrogenic Toxin produced from an abscess.
(is a heat -labile toxin)
(Diarrhea) (Meats and Vegetables)
(enterotoxin similar to E. coli LT)
Epidemiology: At Risk Pops:
- -**Immunosuppression
- -Trauma
- -Indwelling Catheter
- -Contamination of Complex Equipment
Diagnosis:
- -**Rapid ELISA
- -**RPLA-based method
Treatment:
–Supportive
Morphology:
- -Gram Positive Rods
- -**Spores!!
- -Catalase Positive!!
- -Aerobes
- -Motile
- -Non-encapsulated
Common Causes of Food Poisoning
Vomit Big Smelly Chunks
Vibrio
Bacillus Cereus
Staphylococcus aureus
Clostridium perfringens
