Bacterial Virulence and Infection Outcomes
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Questions and Answers

What type of toxins are highly antigenic proteins?

  • Endotoxins
  • Cell-surface toxins
  • Intracellular toxins
  • Exotoxins (correct)

    • How are exotoxins classified?

  • According to their mechanisms and targets (correct)
  • According to their function
  • According to their structure
  • According to their molecular weight

    • What is the role of translocated toxins?

  • To penetrate the host cell
  • To modulate the host cell metabolism (correct)
  • To target the extracellular matrix
  • To damage the cell membrane

    • What type of toxins includes T3SS toxins?

    <p>Intracellular delivered toxins</p> Signup and view all the answers

    What is the target of extracellular matrix toxins?

    <p>Extracellular matrix</p> Signup and view all the answers

    What is the characteristic of AB toxins?

    <p>They are translocated toxins</p> Signup and view all the answers

    What is the function of intracellular toxins?

    <p>To modulate the host cell metabolism</p> Signup and view all the answers

    What type of toxins targets the cell-surface?

    <p>Cell-surface toxins</p> Signup and view all the answers

    How do exotoxins enter the host cell?

    <p>Through translocation</p> Signup and view all the answers

    What is the stage before the infection occurs?

    <p>Exposure</p> Signup and view all the answers

    What is the outcome of an infection where the individual is infected but does not show any symptoms?

    <p>Infection → subclinical disease</p> Signup and view all the answers

    What type of carrier is an individual who is recovering from the disease but still sheds the pathogen?

    <p>Convalescent carrier</p> Signup and view all the answers

    What is the outcome of an infection where the individual is infected and shows symptoms, then recovers?

    <p>Infection → disease → recovery</p> Signup and view all the answers

    What type of carrier is an individual who has recovered from the disease but still sheds the pathogen?

    <p>Persistent carrier</p> Signup and view all the answers

    What is the outcome of an infection where the individual is infected but does not show any symptoms and is a carrier?

    <p>Infection → subclinical disease</p> Signup and view all the answers

    What type of carrier is an individual who is incubating the pathogen but not yet ill?

    <p>Incubatory carrier</p> Signup and view all the answers

    What is the outcome of an infection where the individual is infected, shows symptoms, and then dies or becomes disabled?

    <p>Infection → disease → death/disability</p> Signup and view all the answers

    What type of carrier is an individual who is infected with a clinical infection in a peracute, acute, or chronic phase?

    <p>Clinical carrier</p> Signup and view all the answers

    What is the primary function of virulence factors in bacteria?

    <p>To enable bacteria to colonize and produce disease</p> Signup and view all the answers

    Which of the following is NOT a function of surface-associated proteins?

    <p>Flagella production</p> Signup and view all the answers

    What is the role of quorum-sensing in bacterial virulence?

    <p>Regulation of virulence gene expression</p> Signup and view all the answers

    What is the function of pili in bacterial virulence?

    <p>Adhesion</p> Signup and view all the answers

    How do efflux pumps contribute to bacterial virulence?

    <p>By resisting antibiotics</p> Signup and view all the answers

    What is the function of the capsule in bacterial virulence?

    <p>To protect the bacteria from the immune system</p> Signup and view all the answers

    What is the role of two-component systems in bacterial virulence?

    <p>Regulation of virulence gene expression</p> Signup and view all the answers

    What is the function of LPS in bacterial virulence?

    <p>To induce inflammation</p> Signup and view all the answers

    What is the purpose of quorum-sensing in bacterial virulence?

    <p>To coordinate expression of bacterial genes in response to population density</p> Signup and view all the answers

    What is the role of flagella in bacterial virulence?

    <p>To enhance motility, adhesion, and biofilm formation</p> Signup and view all the answers

    What is the role of secretion systems in bacterial virulence?

    <p>To deliver virulence factors</p> Signup and view all the answers

    What is the result of encapsulation in Streptococcus?

    <p>Increased virulence and invasion of the bloodstream</p> Signup and view all the answers

    What is the function of flagella in bacterial virulence?

    <p>To enable motility</p> Signup and view all the answers

    What is the critical threshold concentration of pheromones required for quorum-sensing?

    <p>A defined density of bacterial population</p> Signup and view all the answers

    What is the function of autoinducers in quorum-sensing?

    <p>To coordinate expression of bacterial genes in response to population density</p> Signup and view all the answers

    What is the primary function of biofilms in terms of bacterial virulence?

    <p>To provide protection from the immune system and antibiotics</p> Signup and view all the answers

    Which of the following is a mechanism of transferring virulence factors between bacteria?

    <p>All of the above</p> Signup and view all the answers

    What is the composition of the self-produced matrix in biofilms?

    <p>Proteins, polysaccharides, and released DNA</p> Signup and view all the answers

    What is a consequence of the transfer of virulence factors among bacteria?

    <p>Emergence of antimicrobial drug resistance</p> Signup and view all the answers

    What is the benefit of biofilms in terms of nutrient acquisition?

    <p>Enhanced ability to uptake nutrients from the environment</p> Signup and view all the answers

    What is the role of conjugation in the transfer of virulence factors?

    <p>Transfer of plasmids containing virulence factor genes</p> Signup and view all the answers

    What is the effect of biofilms on the interaction between bacteria and the host immune system?

    <p>Biofilms provide protection from the immune system</p> Signup and view all the answers

    What is the consequence of the selection of serious pathogenic strains in the clinic?

    <p>Increased antibiotic resistance</p> Signup and view all the answers

    What is the primary function of transformation in the transfer of virulence factors?

    <p>Uptake of free DNA from the environment</p> Signup and view all the answers

    What is the primary function of peptidoglycan in bacterial cell walls?

    <p>Provides structural support</p> Signup and view all the answers

    Which type of fungal infection affects the lungs and other organs?

    <p>Aspergillosis</p> Signup and view all the answers

    What is the function of adhesins in bacterial virulence?

    <p>Facilitate bacterial attachment to host cells</p> Signup and view all the answers

    What is the function of lipopolysaccharides in bacterial cell walls?

    <p>Involved in outer membrane structure</p> Signup and view all the answers

    What is the purpose of siderophores in bacterial iron acquisition?

    <p>To scavenge iron from the host</p> Signup and view all the answers

    Which of the following is NOT a type of fungal infection?

    <p>Pneumonia</p> Signup and view all the answers

    What is the function of capsules in bacterial virulence?

    <p>All the above</p> Signup and view all the answers

    What is a characteristic symptom of Toxic Shock Syndrome?

    <p>All of the above</p> Signup and view all the answers

    What is the primary method by which bacteria acquire iron from the host?

    <p>All of the above</p> Signup and view all the answers

    Match to following to the correct Virulence factor.

    <p>Quorum-sensing = Virulence gene expression control Virulence factor delivery = Secretion systems Virulence factor regulation = Two component system Pili = Adhesion/DNA uptake</p> Signup and view all the answers

    Match the definition to the following term.

    <p>Measurement of pathogenicity = Virulence Biological mechanisms that lead to a disease = Pathogenesis Bacterial characteristis that contribute to virulence = Virulence factors Ability to cause disease = Pathogenicity</p> Signup and view all the answers

    Study Notes

    Stages of Infection

    • Exposure: the time period before infection, where the bacterium is shed by an individual
    • Colonization: bacteria adhere to and multiply on a host surface
    • Infection outcomes:
      • No colonization
      • Infection → disease → recovery
      • Infection → subclinical disease (carrier state)
      • Infection → disease → death/disability
      • Infection → disease → persistence (carriers)

    Disease Carriers

    • Incubatory carrier: carrier that is incubating the pathogen but not yet ill
    • Convalescent carrier: those who are recovering but continue shedding the pathogen
    • Persistent carrier: the animal recovered from the disease but could not eradicate the pathogen
    • Healthy carrier (subclinical): carrier state without clinical symptoms but shed the pathogen
    • Clinical carrier: infectious animal with a clinical infection in a peracute, acute, or chronic phase

    Virulence Factors

    • Enable processes such as:
      • Adhesion
      • Biofilm formation
      • Motility
      • Toxin secretion
      • Immune evasion
      • Colonization
      • Bacterial cell-cell communication
    • Types of virulence factors:
      • Surface-associated proteins
      • Pili
      • Flagella
      • Efflux pumps
      • Siderophore secretion
      • Exotoxins
      • Capsule

    Highlighted Virulence Factors

    • Exotoxins:
      • Secreted by the bacteria
      • Highly antigenic proteins
      • Classified according to mechanisms and targets
      • Can modulate host cell metabolism
    • Capsule:
      • Protects bacteria from the immune system
      • Example: encapsulated strains of Streptococcus are more virulent than non-encapsulated strains
    • Quorum-sensing:
      • Regulation of gene expression in response to fluctuations in cell population density
      • Mediated by chemical signal molecules (autoinducers)
    • Flagella:
      • Motility
      • Adhesion
      • Participates in biofilm formation
      • Modulates the immune system of eukaryotic cells
    • Biofilm:
      • Clusters of bacteria attached to a surface and/or to each other and embedded in a self-produced matrix
      • Functions:
        • Protection from immune system
        • Protection from desiccation
        • Protection from antibiotics
        • Improved acquisition of nutrients
        • Improved bacterial-bacterial interactions

    Transfer of Virulence Factors

    • Methods of transfer:
      • Transformation (acquiring free DNA from the environment)
      • Transduction (bacteriophages transferring bacterial DNA)
      • Conjugation (transfer of plasmids between bacteria)
    • Implications:
      • Emergence and dissemination of antimicrobial drug resistance
      • Selection of serious pathogenic strains in the clinics

    Toxic Shock Syndrome

    • Caused by bacterial toxins, particularly TSST-1, produced by Staphylococcus aureus
    • Characterized by fever, hypotension, rash, diarrhea, and mucous membrane involvement
    • Typically affects menstruating women using tampons
    • Can be fatal if left untreated

    Iron Acquisition Mechanisms

    • Bacteria require iron for growth and survival
    • Siderophores are secreted molecules that chelate iron, allowing bacteria to scavenge iron from host
    • Hemophores bind to hemoglobin and extract iron
    • Direct uptake allows bacteria to take up iron directly from the host

    Infectious Disease Pathophysiology

    • Inoculation: pathogen enters the host
    • Colonization: pathogen multiplies and establishes itself
    • Invasion: pathogen penetrates host tissues
    • Toxin production: pathogen produces toxins that cause harm
    • Immune response: host responds to infection
    • Disease: clinical symptoms manifest

    Cell Wall Components

    • Bacterial cell walls are composed of peptidoglycan (also known as murein), providing structural support
    • Teichoic acids are found in Gram-positive bacteria and are involved in cell wall formation
    • Lipoteichoic acids are found in Gram-positive bacteria and are involved in cell wall formation
    • Lipopolysaccharides are found in Gram-negative bacteria and are involved in outer membrane structure

    Fungal Infections

    • Candidiasis is caused by Candida species and affects skin, mucous membranes, and internal organs
    • Aspergillosis is caused by Aspergillus species and affects lungs and other organs
    • Cryptococcosis is caused by Cryptococcus species and affects lungs and central nervous system
    • Fungal infections often occur in immunocompromised individuals

    Bacterial Virulence Factors

    • Adhesins are molecules that facilitate bacterial attachment to host cells
    • Invasins are molecules that facilitate bacterial invasion of host cells
    • Toxins are molecules that harm host cells
    • Capsules are polysaccharide layers that protect bacteria from host immune system
    • Biofilms are complex communities of bacteria that resist host immune system and antimicrobial agents

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    Related Documents

    Bacteriology II - PID Dr. Gutierrez PDF

    Description

    This quiz covers the stages of bacterial infection, from exposure to infection outcomes, including colonization and disease. Test your knowledge of bacterial virulence and its effects.

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