Bacterial Invasion Mechanisms Quiz Part 1, Med Level

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What is the role of virulence factors in the invasion process of pathogens?

Prevent pathogens from producing exoenzymes

Allow pathogens to colonize and damage host tissues (correct)

Increase the likelihood of pathogens being eliminated by humoral antibodies

Help pathogens disseminate through local tissues

What distinguishes obligate intracellular pathogens from facultative intracellular pathogens?

Ability to reproduce outside of host cells

Tendency to produce exoenzymes

Inability to reproduce outside of host cells (correct)

Reliance on cellular immune response for elimination

What benefit do bacterial pathogens gain by living inside host cells?

Enhanced protection against immune system defenses (correct)

Reduced access to nutrients in the host cell

Exposure to humoral antibodies

Increased competition from other microbes

How do facultative intracellular pathogens differ from obligate intracellular pathogens?

Obligate intracellular pathogens can only reproduce inside host cells Signup and view all the answers

How do pathogens utilize the host cell actin cytoskeleton to move in the cytosol of infected cells?

By forming membrane protrusions Signup and view all the answers

What is the mechanism through which Listeria first invades host cells?

Interaction of InlA and InlB with host cell surface receptors E-cadherin and Met Signup and view all the answers

How does Listeria escape from phagosomes before fusion with lysosomes occurs?

By acting on vacuoles using LLO and PC-PLC Signup and view all the answers

What is the role of actin polymerization in the spreading of Listeria?

Promotes cell-to-cell spreading of Listeria Signup and view all the answers

How does the trigger mechanism facilitate the entry of bacteria into host cells?

Bacteria attach to host cell surface and deliver effector proteins Signup and view all the answers

What differentiates the zipper mechanism from the trigger mechanism in terms of bacterial entry into host cells?

It involves the fusion of actin-driven pseudopods in a zippering process Signup and view all the answers

Which group of effectors play a role in inducing massive localised rearrangements of actin and plasma membrane during 'trigger'-mediated invasion of host cells?

SipA, SopB, SopE2, SipC Signup and view all the answers

In Salmonella and Shigella invasion of intestinal epithelial cells, what process is triggered by effector molecules secreted by the pathogens?

Membrane ruffling Signup and view all the answers

Which method does Yersinia pseudotuberculosis primarily rely on to invade host cells?

'Trigger' mechanism with surface proteins Signup and view all the answers

What role do effector proteins play in the 'trigger' mechanism for pathogen entry into host cells?

Secretion into the host cell to regulate actin dynamics Signup and view all the answers

How do bacterial pathogens avoid intracellular killing by lysosomes?

By promoting phagosomal membrane disruption Signup and view all the answers

What is the role of beta-1 integrins in the infection process?

Facilitating efficient translocation across the intestinal epithelial barrier Signup and view all the answers

How do Mycobacterium tuberculosis, Legionella pneumophila, and Salmonella evade being digested by phagocytes?

By preventing phagosomal lysis Signup and view all the answers

Which bacterial species utilize the SPI-2 encoded T3SS-2 to prevent fusion of the phagosome with lysosomes in macrophages?

Salmonella Signup and view all the answers

How do Listeria monocytogenes and Shigella avoid being digested by lysosomes?

By preventing phagosomal lysis Signup and view all the answers

What is the mechanism through which Shigella escapes from the phagosome/endosome?

Secretion of IpaB protein Signup and view all the answers

Which type of cells do a subset of intracellular pathogens disseminate within via cell-to-cell spread?

Epithelial and endothelial cells Signup and view all the answers

What selective advantage does proliferation in a membrane-bound compartment provide to intracellular pathogens?

Enhanced protection against immune recognition Signup and view all the answers

How do bacterial pathogens escape intracellular killing in a vacuole?

Promoting vacuolar membrane disruption Signup and view all the answers

What is the primary function of ZIPPER during bacterial infection?

Facilitating bacterial translocation across host cell barriers Signup and view all the answers

Which mechanism allows Salmonella to proliferate within macrophages while avoiding digestion?

Preventing fusion of phagosome with lysosome Signup and view all the answers

How do some intracellular pathogens facilitate their escape from phagosomes?

Secreting proteins that lyse the phagosome early on Signup and view all the answers