Term
Corynebacterium diphtheriae |
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Definition
Disease: Diphtheria Characteristics: - Club shaped gram + rods, V or L shaped
- Metachromatic granules
- Aerobic, non-spore forming
Habitat and Transmission: Throat. Human to human. Respiratory Droplets
Pathogenesis: - Exotoxin that inhibits protein synthesis by adding ADP-ribose to EF-2.
- Subunit A - ADP ribosylating activity
- Subunit B - binds to cell surface
Clinical Findings: - Pseudomembrane over tonsils and throat.
- Complications
- Airway blockage
- Myocarditis
- Nerve Weakness or Paralysis
Lab Dx: - Gram + and culture Metachromatic granules
- Black colonies on tellurite plate
- Document toxin production with precipitin test
Tx: Antitoxin, penicillin G Prevention: Toxoid vaccine.
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Term
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Definition
Diseases: Meningitis and sepsis in newborns and immunocompromised adults
Characteristics: - Gram + rods, Aerobic, non spore-forming
Habitat and Transmission: GI and female genital tracts. Animals, plants and soil. Transmision across placenta or during delivery. Ingestion of unpasteurized milk products. Pathogenesis: - Listeriolysin is exotoxin that degrades cell membranes
- Intracellular that moves cell to cell via "actin rockets"
Clinical Findings: - Gastroenteritis in adults
- Diarrhea, fever, headhache, myalgias, and cramps
- Little vomiting
Lab Dx: - Gram + and culture
- β-hemolytic
- Tumbling motility
Tx: Trimethoprim-sulfamethoxazole (crx BBB). Ampicillin Prevention: Avoidance of unpasteurized milk products. |
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Term
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Definition
Facultative gram-variable rod associated w/ bacterial vaginosis - malodorous vaginal discharge and clue cells (epithelial cells covered in bacteria)
- "whiff test" -> KOH gives "fishy" odor
- must R/O trichomoniasis which is also whiff test +.
Drug of choice: metronidazole |
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Term
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Definition
Disease: Anthrax, Woolsorters' disease Characteristics: - Aerobic gram + spore-forming rods
- Capsule of poly-D-glutamate
Habitat and Transmission: Soil. Transmision by contact with infected animals or inhalation of spores.
Pathogenesis: - 3 proteins in toxin
- Edema factor
- an adenylate cyclase that ↑ cAMP and causes edema
- Lethal Factor
- kills the cell by inhibiting signal transduction
- Protective antigen
- mediates entry of other 2 proteins
- Anti-phagocytic capsule
Clinical Findings: - Cutaneous anthrax
- Malignant pustule - painless ulcer with edema
- Black eschar
- Pulmonary anthrax
- Begins with nonspecific respiratory Sx.
- Rapidly progresses to hemorrhagic mediastinitis, bloddy pleural effusions, septic shock, and death
- Mediastinal widening
Lab Dx: - Gram + plus aerobic culture
- nonmotile
- Rise in antibody titer in indirect hemagglutination test is diagnostic
Tx: Antitoxin, ciprofloxacin or doxycline. penicillin G Prevention: Vaccine of protective Ag. |
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