Ehrlichia and Anaplasma — Flashcards

Flashcard 1: Rickettsia spp. is an _____ _____ because it requires host CoA and NAD+

Answer: obligate intracellular organism

Flashcard 2: What is the etiology of Endemic Typhus?_____

Answer: Rickettsia typhi

Flashcard 3: Mycoplasma pneumoniae requires _____ to grow, which is present in Eaton's Agar

Answer: cholesterol

Flashcard 4: Why doesn't Rickettsia gram stain well?_____

Answer: Intracellular parasite

Flashcard 5: Which Rickettsia spp. can result in pneumonia?_____

Answer: Rickettsia prowazekii

Flashcard 6: What is the vector for Epidemic Typhus (Rickettsia prowazeki)?_____

Answer: Human Body Louse

Flashcard 7: Name the clinical presentation, culture medium, and treatment for Mycoplasma pneumoniae.

Answer: • Clinical: Atypical "walking" pneumonia • Culture: Eaton's agar • Treatment: Macrolides or Fluoroquinolones

Extra: Note: Mycoplasma pneumoniae lacks a cell wall, making it naturally resistant to penicillins and cephalosporins. It is associated with high titers of cold agglutinins (IgM).

Flashcard 8: What are the key associations to remember for cold agglutinin?

Answer: IgM, Mycoplasma, Mononucleosis (EBV)

Flashcard 9: Mycoplasmal pneumonia (Most common cause)

Answer: Which organism is the most common cause of atypical pneumonia (walking pneumonia)?::Mycoplasma pneumoniae (Eaton agent)

Extra: • Features: Insidious onset, headache, nonproductive cough, and diffuse interstitial infiltrates. • Patient profile: Young adults (<30 y/o), military recruits, and prisoners. • Diagnosis: PCR, Cold agglutinins (IgM), culture on Eaton agar. • Treatment: Macrolides (e.g., Azithromycin), Doxycycline, or Fluoroquinolones. • Note: Lacks a cell wall (does not stain on Gram stain; resistant to β-lactams).

Flashcard 10: What factor explains Mycoplasma's inability to Gram stain?

Answer: no cell wall!