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Which stage of the infectious disease process involves adherence to host surfaces?
Which stage of the infectious disease process involves adherence to host surfaces?
What does the 'iceberg' concept of infectious disease emphasize about asymptomatic infections?
What does the 'iceberg' concept of infectious disease emphasize about asymptomatic infections?
Which of the following is NOT considered a physical or chemical barrier to prevent bacterial infection?
Which of the following is NOT considered a physical or chemical barrier to prevent bacterial infection?
In the iceberg concept, which section represents the asymptomatic infections?
In the iceberg concept, which section represents the asymptomatic infections?
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What is the major role of asymptomatically infected individuals in a community?
What is the major role of asymptomatically infected individuals in a community?
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What term describes the ability of a microbial species to produce disease?
What term describes the ability of a microbial species to produce disease?
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Which type of infection is characterized by the first infection by a pathogen in a new host?
Which type of infection is characterized by the first infection by a pathogen in a new host?
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What is the minimum number of bacteria required to produce clinical evidence of infection called?
What is the minimum number of bacteria required to produce clinical evidence of infection called?
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Which type of infection occurs due to a new pathogen infecting a host already suffering from an existing disease?
Which type of infection occurs due to a new pathogen infecting a host already suffering from an existing disease?
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Which term describes localized infections with generalized systemic effects?
Which term describes localized infections with generalized systemic effects?
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What do we call the state when some pathogens remain dormant after primary infection and may cause disease later?
What do we call the state when some pathogens remain dormant after primary infection and may cause disease later?
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Which type of infection is specifically induced by a physician during treatment or procedures?
Which type of infection is specifically induced by a physician during treatment or procedures?
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What is the difference in virulence among strains of the same organism caused by the expression of certain factors called?
What is the difference in virulence among strains of the same organism caused by the expression of certain factors called?
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What is the presence of bacteria in the blood known as?
What is the presence of bacteria in the blood known as?
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Which type of infection arises from the host's own body?
Which type of infection arises from the host's own body?
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What is the primary role of pili or fimbriae in bacterial function?
What is the primary role of pili or fimbriae in bacterial function?
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Which organism is specifically associated with the use of Colonization Factor Antigens (CFA)?
Which organism is specifically associated with the use of Colonization Factor Antigens (CFA)?
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What distinguishes a capsule from a slime layer in bacterial structures?
What distinguishes a capsule from a slime layer in bacterial structures?
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Which of the following is NOT a characteristic of biofilm formation?
Which of the following is NOT a characteristic of biofilm formation?
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How do bacterial capsules help in immune evasion?
How do bacterial capsules help in immune evasion?
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What is a key feature of the filamentous haemagglutinin (FHA) produced by Bordetella pertussis?
What is a key feature of the filamentous haemagglutinin (FHA) produced by Bordetella pertussis?
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Which of the following bacteria is associated with biofilm formation in implanted devices?
Which of the following bacteria is associated with biofilm formation in implanted devices?
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What allows pili to confer host specificity in bacteria?
What allows pili to confer host specificity in bacteria?
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What is one of the main consequences of exposure to high levels of endotoxin?
What is one of the main consequences of exposure to high levels of endotoxin?
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Which of the following cytokines is primarily activated by endotoxin?
Which of the following cytokines is primarily activated by endotoxin?
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Which bacteria is most commonly associated with endotoxic (septic) shock?
Which bacteria is most commonly associated with endotoxic (septic) shock?
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What systemic effect is NOT caused by high doses of endotoxin?
What systemic effect is NOT caused by high doses of endotoxin?
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How does endotoxin primarily induce its effects?
How does endotoxin primarily induce its effects?
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What effect does tetanospasmin have on skeletal muscles?
What effect does tetanospasmin have on skeletal muscles?
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What neurotransmitter is primarily affected by botulinum toxin?
What neurotransmitter is primarily affected by botulinum toxin?
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Which of the following describes the action of botulinum toxin?
Which of the following describes the action of botulinum toxin?
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Inhibitory neurotransmitters include which of the following?
Inhibitory neurotransmitters include which of the following?
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What type of paralysis is associated with botulism?
What type of paralysis is associated with botulism?
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Which structure is primarily responsible for the production of botulinum toxin?
Which structure is primarily responsible for the production of botulinum toxin?
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What is the main physiological effect of tetanospasmin on the body?
What is the main physiological effect of tetanospasmin on the body?
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What type of toxin is botulinum toxin classified as?
What type of toxin is botulinum toxin classified as?
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What type of appearance do capsules give to bacterial colonies?
What type of appearance do capsules give to bacterial colonies?
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Which stain is used to demonstrate bacterial capsules under a light microscope?
Which stain is used to demonstrate bacterial capsules under a light microscope?
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Which enzyme is responsible for breaking down the connective tissue component hyaluronic acid?
Which enzyme is responsible for breaking down the connective tissue component hyaluronic acid?
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What type of bacteria are endotoxins characteristic of?
What type of bacteria are endotoxins characteristic of?
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What do exotoxins typically consist of?
What do exotoxins typically consist of?
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Which enzyme produced by Staphylococcus aureus helps in creating a fibrin barrier?
Which enzyme produced by Staphylococcus aureus helps in creating a fibrin barrier?
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What is the main function of urease produced by Proteus and H. pylori?
What is the main function of urease produced by Proteus and H. pylori?
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Which of the following enzymes breaks down red blood cells?
Which of the following enzymes breaks down red blood cells?
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Study Notes
Bacterial Pathogenesis
- Bacterial pathogenesis is the process of disease production by bacteria.
- Pathogenicity refers to the ability of a microbial species to produce disease.
- Virulence is the relative degree of pathogenesis, which can vary between strains of the same organism based on virulence factor expression.
- Virulence factors influence how bacteria cause disease and how they overcome host defenses.
Types of Infection
- Primary infection: Initial infection with a new pathogen.
- Reinfection: Subsequent infection with the same pathogen.
- Secondary infection: New infection due to immunodeficiency caused by a primary infection.
- Focal infection: Localized infection in organs or tissues (e.g., tonsils, appendix, dental abscess). Can spread systemically.
- Cross-infection: New infection in a patient already suffering from a disease, often seen in hospitals.
- Latent infection: Some pathogens remain dormant in tissues after primary infection and multiply when host resistance is lowered.
- Co-infection: Simultaneous infection by multiple pathogens (e.g., HBV and HDV).
- Bacteremia: Bacteria circulating in the bloodstream.
- Septicemia: Bacteria circulating and multiplying in the bloodstream, leading to toxic products and a high fever.
- Iatrogenic infection: Infection induced by a physician's procedure.
- Exogenous infection: Infection from external sources.
- Endogenous infection: Infection from the host's own body.
- Inapparent infection: Infection without clinical symptoms.
- Atypical infection: Infection with atypical or non-classical clinical features.
- Nosocomial Infection: Hospital-acquired infection.
Medical Terms
- Minimum Infective Dose (MID): Minimum inoculum size or number of bacteria to initiate infection.
- Minimum Lethal Dose (MLD): Minimum number of bacteria needed to cause host death.
- Normal Flora: Microorganisms that continuously inhabit the human body (without harm).
Chain of Infection
- Infectious Agent: The causative microorganism
- Reservoir: Location where the microbe thrives
- Entry: Portal of entry into the host
- Transmission: Method of spreading the microbe
- Exit: Portal of exit from the host
- Susceptible Host: Host susceptible to contracting the disease
Bacterial Disease Mechanisms
- Transmission from sources or infected individuals (epidemiological triad).
- Entry into human body.
- Overcome host defenses.
- Multiply and disseminate within the body (adhere to host surfaces, invade cells, cause damage).
- Spread to other members of the population.
Virulence Factors
- Adhesins: (pili/fimbriae/adhesins) mediate attachment to host cells.
- Capsules/Slime: protect Bacteria, evade immunity and enhance adherence.
-
Toxins: (endotoxins or exotoxins) cause damage by damaging cells or disrupting cellular metabolism.
- Endotoxins: integral component of the cell wall, released when the cell dies, usually lipopolysaccharides unique to gram-negative bacteria.
- Exotoxins: heat-labile protein secreted by bacteria.
Examples of Important Bacterial Virulence Factors
- Pili/fimbriae: Appendages aiding attachment to host cells (e.g., Neisseria gonorrhoeae, Escherichia coli).
- Non-fimbrial adhesins: (e.g., Bordetella pertussis - filamentous haemagglutinin (FHA)).
- Capsules: Polysaccharide/protein coat, evade immunity (e.g., Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis).
- Toxins: Clostridium perfringens (alpha toxin/Lecithinase, perfringolysin 0), Corynebacterium diphtheriae (diphtheria toxin), Vibrio cholerae (cholera toxin), Clostridium tetani (tetanospasmin), Clostridium botulinum (botulinum toxin)) causing damage from modifying intracellular targets and/or acting on nerve-muscle transmission.
Host Factors in preventing infection:
- Physical and chemical barriers (e.g., skin, acid in stomach, mucous).
- Innate immune responses (e.g., complement, phagocytosis).
- Adaptive immune responses (e.g., antibodies, cell-mediated immunity).
Systemic Effects of High Doses of Endotoxin:
- Fever.
- Hypotension.
- Shock.
- Weakness.
- Blood coagulation (DIC).
- Inflammation.
- Intestinal hemorrhage.
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Description
Explore the mechanisms of bacterial pathogenesis and the various types of infections they cause. This quiz covers concepts like pathogenicity, virulence, and different infection types such as primary, secondary, and latent infections. Understand how bacteria interact with hosts and the implications for health.
