Gram-negative — Flashcards

Flashcard 21: What is the most common clinical manifestation of Enterotoxigenic E. coli (ETEC)?

Answer: Traveler's diarrhea (watery diarrhea)

Extra: ETEC is the most common cause of traveler's diarrhea. It produces heat-labile (LT) and heat-stable (ST) enterotoxins.

Flashcard 22: Clinical presentation and mechanism of Enteroinvasive E. coli (EIEC)

Answer: Causes dysentery similar to Shigella (invades intestinal mucosa)

Extra: Mechanism: Invades colonic epithelium and causes inflammatory diarrhea/dysentery. Features are clinically indistinguishable from Shigellosis.

Flashcard 23: Pseudomonas aeruginosa produces a characteristic _____ pigment.

Answer: blue-green

Flashcard 24: Pseudomonas aeruginosa has a distinctive _____ odor.

Answer: grape-like

Flashcard 25: Legionnaire's disease

Answer: Legionella pneumophila

Extra: Severe pneumonia, fever, GI and CNS symptoms; Hyponatremia. Treatment: Macrolide or fluoroquinolone.

Flashcard 26: What are the specific growth requirements for Legionella pneumophila on Buffered Charcoal Yeast Extract (BCYE) agar?

Answer: Iron and Cysteine

Extra: Legionella pneumophila is a Gram-negative bacillus. Stain: Silver stain (Gram stain poorly). Clinical: Legionnaire's disease (pneumonia + diarrhea + hyponatremia) and Pontiac fever. Treatment: Macrolides or Quinolones.

Flashcard 27: How is N. gonorrhoeae transmitted?

Answer: Sexual contact or birth (vertical transmission)

Flashcard 28: What are the key characteristics and clinical findings associated with Neisseria meningitidis?

Answer: Gram-negative diplococci; causes meningitis, meningococcemia, and Waterhouse-Friderichsen syndrome.

Extra: Treatment: Ceftriaxone or Penicillin G. Prophylaxis for close contacts: Rifampin, Ciprofloxacin, or Ceftriaxone. Key features: Maltose and Glucose fermenter, Polysaccharide capsule.

Flashcard 29: Gram negative bacilli are _____ to penicillin G.

Answer: resistant

Flashcard 30: Gram negative organisms stain _____.

Answer: pink