Klebsiella pneumoniae Lipopolysaccharides (LPS) Overview

This set of flashcards provides a comprehensive overview of the structural, immune evasion, antibiotic resistance, and immunological implications of Klebsiella pneumoniae lipopolysaccharides (LPS).

What role does Lipid A play in Klebsiella pneumoniae?

Lipid A acts as the hydrophobic anchor of LPS, activating the host immune system by interacting with TLR4 on immune cells.

How does the core polysaccharide of LPS contribute to Klebsiella pneumoniae's structure?

The core polysaccharide links Lipid A to the O-antigen and contains conserved sugars, aiding in bacterial resistance to immune attacks.

What is the significance of the O-antigen in Klebsiella pneumoniae?

The O-antigen determines the serotype of Klebsiella pneumoniae and is crucial for immune evasion.

What mechanisms allow Klebsiella pneumoniae to evade complement-mediated killing?

Klebsiella pneumoniae uses its O-antigen to prevent complement proteins from binding, reducing MAC formation.

How does Klebsiella pneumoniae modify Lipid A to reduce immune activation?

Klebsiella pneumoniae adds chemical modifications to Lipid A, making it less recognizable by TLR4.

What are hypervirulent strains (hvKP) of Klebsiella pneumoniae known for?

They often have unique LPS structures that contribute to increased virulence and resistance to immune defenses.

How does LPS contribute to sepsis and endotoxemia?

LPS release into the bloodstream induces strong cytokine responses leading to inflammation and septic shock.

What challenges exist in developing vaccines against Klebsiella pneumoniae?

The high serotype diversity of LPS complicates the development of a universal vaccine.

How do changes in LPS structure affect antibiotic resistance in Klebsiella pneumoniae?

Altered LPS structure diminishes drug binding and helps bacteria evade action from antibiotics like colistin.

What role do efflux pumps play in antibiotic resistance in Klebsiella pneumoniae?

Efflux pumps expel toxic substances, and their overexpression combined with LPS modifications helps resist multiple drug classes.