Meningococcal Infections and Pathogenesis
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Questions and Answers

What is the primary function of Opa proteins concerning gonococci?

  • Facilitating adhesion within colonies and to host cells (correct)
  • Modifying the surface characteristics of gonococci
  • Decreasing the virulence of gonococci
  • Inhibiting the growth of gonococci

What characteristic change occurs to D.Rmp when it is in a reduced state?

  • Decreases in molecular weight
  • Changes in apparent molecular weight (correct)
  • Increases in functional activity
  • Becomes less immunogenic

Which of the following statements is true regarding the role of Opa proteins?

  • They assist in the immune evasion of gonococci.
  • They are involved in the metabolic processes of gonococci.
  • They solely help in the reproduction of gonococci.
  • They promote the adhesion of gonococci to host cells. (correct)

What type of protein is D.Rmp classified as?

<p>Reduction-modifiable protein (C)</p> Signup and view all the answers

What is a consequence of the adhesion properties of Opa proteins in gonococci?

<p>Strengthened colonization of host tissues (A)</p> Signup and view all the answers

What is the primary role of incorporating human sialic acid derivatives into meningococcal capsules?

<p>To allow the organism to evade the host immune system (B)</p> Signup and view all the answers

What mechanism is described by the incorporation of NANA into meningococcal capsules?

<p>Molecular mimicry (C)</p> Signup and view all the answers

Which of the following best describes sialic acid derivatives like NANA in the context of meningococcal bacteria?

<p>They are carbohydrates that help the bacteria to evade immunity (B)</p> Signup and view all the answers

Which part of the meningococcal structure is most directly affected by the incorporation of NANA?

<p>Capsule (B)</p> Signup and view all the answers

How does molecular mimicry contribute to the virulence of meningococcal bacteria?

<p>By disguising the bacteria from the immune system (C)</p> Signup and view all the answers

What is one of the primary complications associated with fulminant meningococcemia?

<p>Adrenal failure (B)</p> Signup and view all the answers

Which symptom is most characteristic of fulminant meningococcemia?

<p>Hemorrhagic rash (C)</p> Signup and view all the answers

What key process occurs in the meninges during meningitis?

<p>Thrombosis of veins and arteries (C)</p> Signup and view all the answers

What severe outcome can arise from disseminated intravascular coagulation associated with fulminant meningococcemia?

<p>Circulatory collapse (C)</p> Signup and view all the answers

What should be done if immediate incubation of a specimen is not possible?

<p>The specimen should be placed in a CO2-containing transport-culture system. (B)</p> Signup and view all the answers

Which type of white blood cell is primarily involved in the exudation during meningitis?

<p>Polymorphonuclear leukocytes (D)</p> Signup and view all the answers

What type of test can provide presumptive identification of organisms after 48 hours of culture?

<p>A positive oxidase test. (A)</p> Signup and view all the answers

What is typically assessed to identify organisms on a Gram-stained smear?

<p>The size and shape of the organisms. (D)</p> Signup and view all the answers

After 48 hours, which of these findings does NOT indicate presumptive identification of an organism?

<p>The temperature of the incubator has dropped. (D)</p> Signup and view all the answers

In the context of specimen preservation, why is a CO2-containing transport-culture system preferred?

<p>It helps mimic in vivo conditions for the organisms. (D)</p> Signup and view all the answers

What does spinal fluid and blood typically yield in laboratory cultures?

<p>Pure cultures (A)</p> Signup and view all the answers

Which method is NOT mentioned for identifying cultures derived from spinal fluid and blood?

<p>DNA sequencing (D)</p> Signup and view all the answers

What role do carbohydrate oxidative reactions play in identifying pure cultures?

<p>They assist in differentiation of species (C)</p> Signup and view all the answers

What type of serum is used for agglutination in the identification of cultures?

<p>Type-specific serum (B)</p> Signup and view all the answers

What additional procedure follows carbohydrate oxidative reactions in the identification of cultures?

<p>Agglutination tests (C)</p> Signup and view all the answers

Flashcards

Opa proteins

Proteins found on the surface of gonococci that help them attach to host cells and other bacteria, forming colonies.

D.Rmp

A protein in gonococci that undergoes a change in its apparent molecular weight when reduced, suggesting a change in its structure.

Adhesion of gonococci

The ability of Opa proteins to help gonococci stick to surfaces, including host cells, allowing them to establish a strong presence in the body.

Reduction-modifiable protein

A type of protein that changes its structure when exposed to a reducing environment, like the inside of a cell.

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Stronger colonization of host tissues

The consequence of Opa proteins allowing gonococci to stick together and to host cells, resulting in a stronger presence in the body.

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Incorporating human sialic acid derivatives

A process where meningococcal bacteria incorporate human sialic acid derivatives into their capsules, helping them avoid detection by the host's immune system.

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Molecular mimicry

A strategy used by meningococcal bacteria to deceive the immune system by mimicking the body's own molecules, making them less recognizable to immune cells.

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Sialic acid derivatives

Carbohydrates, like NANA, that help meningococcal bacteria evade the immune system by making them look like harmless molecules from the body.

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Meningococcal capsule

The outermost layer of the meningococcal cell, which is modified by the incorporation of NANA to help the bacteria evade the immune system.

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Molecular mimicry and virulence

The way in which molecular mimicry contributes to the ability of meningococcal bacteria to cause disease by hiding from the immune system.

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Adrenal failure

A serious complication of fulminant meningococcemia, characterized by the failure of the adrenal glands to produce essential hormones.

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Hemorrhagic rash

A distinctive characteristic of fulminant meningococcemia, involving the appearance of a widespread, bleeding rash.

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Thrombosis in meningitis

The process that occurs in the meninges (membranes around the brain and spinal cord) during meningitis, involving the blockage of blood vessels.

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Circulatory collapse

A severe consequence of disseminated intravascular coagulation (DIC), which can occur with fulminant meningococcemia, leading to insufficient blood flow throughout the body.

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Specimen preservation for bacteria

The recommended course of action when a specimen cannot be immediately analyzed in the lab, ensuring the bacteria remain viable.

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Polymorphonuclear leukocytes

A type of white blood cell that is abundant during inflammation, particularly in the fluid surrounding the brain and spinal cord during meningitis.

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Presumptive identification of organisms

A test that can be used to tentatively identify certain bacteria, such as those causing meningitis, after a period of growth in a laboratory.

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Gram staining

A standard technique for identifying organisms in a sample, involving staining and examining the size and shape of the bacteria.

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Carbohydrate oxidative reactions

The process of analyzing how bacteria utilize specific carbohydrates, which can help differentiate between different types of bacteria.

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Agglutination tests

A laboratory test that uses specific antibodies to identify and react with specific bacteria, leading to the identification of the causative organism.

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Type-specific serum

A specialized serum containing antibodies specific to different types of bacteria, used in agglutination tests to identify which bacteria is present.

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Pure cultures

The primary outcome of laboratory cultures from spinal fluid and blood, indicating the presence of a single type of bacteria.

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Study Notes

Opa Proteins

  • Adhesion of gonococci within colonies and in attachment of gonococci to host cell receptors.
  • Involved in gonococcal pathogenesis.

Rmp (Protein III)

  • Reduction-modifiable protein (Rmp).
  • Changes apparent molecular weight when in a reduced state.

Specimen Collection and Culture

  • If immediate incubation is not possible, the specimen should be placed in a CO2-containing transport-culture system.
  • Presumptive identification can be achieved 48 hours after culture by Gram-stained smear and a positive oxidase test.

Meningococcal Capsule

  • Incorporation of human sialic acid derivatives (NANA) allows for molecular mimicry, evading host immune system detection.

Fulminant Meningococcemia

  • Characterized by high fever, hemorrhagic rash, disseminated intravascular coagulation, circulatory collapse, bilateral hemorrhagic necrosis of adrenal glands, and subsequent adrenal failure (Waterhouse-Friderichsen syndrome).

Meningitis

  • Acute inflammation of the meninges.
  • Thrombosis of blood vessels and exudation of polymorphonuclear leukocytes.
  • Thick purulent exudate covers the surface of the brain.
  • Spinal fluid and blood typically yield pure cultures identified by carbohydrate oxidative reactions and agglutination with type-specific or polyvalent serum.

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Description

This quiz covers key aspects of meningococcal infections, focusing on proteins involved in adhesion and immune evasion, specimen collection techniques, and the clinical manifestations of fulminant meningococcemia. Understanding these topics is crucial for recognizing and managing meningococcal diseases effectively.

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