Gram-Neg. Bacilli Chapter 20

A set of flashcards covering the key concepts from the lecture on Gram-negative bacilli of medical importance.

What are the characteristics of Gram-negative bacilli aerobes?

They do not ferment carbohydrates.

Name three Gram-negative bacilli that are lactose-fermenting.

Escherichia, Klebsiella, Citrobacter.

Which bacteria are classified as non-lactose-fermenting Gram-negative bacilli?

Haemophilus, Salmonella, Shigella, Hafnia, Edwardsiella, Pasteurella, Proteus, Serratia, Providencia, Yersinia, Morganella.

What is a common trait of obligate anaerobes like Bacteroides?

They do not require oxygen for growth.

What type of infections can Pseudomonas aeruginosa cause?

Opportunistic infections in immunocompromised patients.

What features allow Pseudomonas aeruginosa to evade phagocytosis?

Biofilm and various virulence factors.

What disease does Bordetella pertussis cause?

Pertussis, commonly known as whooping cough.

How do Bordetella pertussis virulence factors contribute to disease?

They mediate the disease through adhesins and toxins.

What is Legionnaires' disease, and how is it treated?

It results in pneumonia and can be treated with fluoroquinolone and azithromycin.

What is the significance of the oxidase test in microbiology?

It distinguishes between the Enterobacteriaceae and Pasteurellaceae families.

What are coliforms typically characterized by?

They are Gram-negative, rod-shaped bacteria that ferment lactose.

What are some common symptoms of gastroenteritis caused by E. coli?

Diarrhea, cramps, nausea, and vomiting.

How does Klebsiella pneumoniae avoid immune responses?

Its capsule protects against phagocytosis.

What distinguishes Serratia marcescens in lab cultures?

It produces a red pigment when grown at room temperature.

What is the primary association of Proteus mirabilis infections?

Urinary tract infections, especially in patients with urinary catheters.

What are Salmonella commonly associated with?

Food contaminated with animal feces, especially poultry and eggs.

What are the significant diseases caused by Salmonella enterica serotype Typhi?

Gastroenteritis, bacteremia, and peritonitis.

What is Shigella's main virulence factor?

Enterotoxin that induces diarrhea.

What role do virulence plasmids play in Yersinia species?

They contain adhesins and proteins that induce apoptosis of immune cells.

What distinguishes pathogenic Enterobacteriaceae from others?

They produce type III secretion systems and exhibit numerous virulence factors.

What is the significance of the Hib vaccine?

It has eliminated most diseases caused by H. influenzae type b in the U.S.

What diseases can Haemophilus influenzae cause?

Conjunctivitis, sinusitis, dental abscesses, and meningitis.

Who is primarily affected by pertussis?

It is most common in children.

What does the term 'facultative anaerobe' mean in relation to Gram-negative bacilli?

They can grow in both the presence and absence of oxygen.

What is a key diagnostic indicator for Shigella infection?

S. dysenteriae, which produces severe enterotoxin.