Microbial Virulence Flashcards
(50 cards)
What is microbial virulence?
Measure of pathogenicity in a susceptible host
Virulence is a critical factor in the ability of a microbe to cause disease.
What is host susceptibility?
Person lacking immunity or resistance to a pathogen
Increased risk of infection due to various factors.
What is the relationship between virulence and infection?
Virulent microbe + susceptible host = infection
This equation highlights the necessity of both factors for infection to occur.
List the barriers to infection.
- Intact skin and mucous membranes
- Mucous
- Antibacterial secretions
- Presence of the microbiome
- Innate/adaptive immunity
Disruptions to these barriers can increase host susceptibility.
What are virulence factors?
Gene products that enable colonization of a susceptible host
These factors play a crucial role in the ability of pathogens to cause disease.
Identify some factors that contribute to host susceptibility.
- Age
- Comorbidities
- Lifestyle
- Genetics
- Immunization
- Medical interventions
- Medications
- Trauma
- Socioeconomic factors
These factors can significantly increase the risk of infection.
What role do biofilms play in infections?
Bacteria embedded in a sticky matrix, more resistant to removal by host immunity and antimicrobials
50-80% of infections are associated with biofilms.
True or False: All pathogens require a susceptible host for infection.
False
Obligate pathogens have specialized virulence factors that allow them to infect without a susceptible host.
What is the significance of antimicrobial resistance in Pseudomonas aeruginosa infections?
Complicates treatment and often requires combinations of antimicrobials
This resistance is a major concern in clinical settings.
Fill in the blank: The immune response against pathogens can cause _______.
[damage to host tissues]
Both the pathogen and the immune response contribute to pathology.
What are some microbial factors that contribute to pathogenesis?
- Toxins
- Enzymes
- Biofilms
- Immune evasion
These factors can directly damage host cells.
Define pathogenicity.
Ability of a microbe to cause infection
It reflects the potential of a microbe to lead to disease.
What is the role of antigenic variation in viral infections?
Ensures previous immune memory functions less well
This can lead to more severe infections as the immune system may not recognize the new epitopes.
What are the two types of host-mediated pathogenesis?
- Prolonged inflammatory responses
- Delayed immune responses
Both can contribute to increased pathology.
How do microbes cause disease in susceptible hosts?
By attaching, resisting host defenses, and multiplying
This process is essential for establishing an infection.
List key virulence factors of Pseudomonas aeruginosa.
- Biofilms
- Capsules
- Immune evasion
- Motility
- Adhesins
- Enzymes
- Toxins
These factors enable the pathogen to survive and cause disease.
Fill in the blank: _______ are important for controlling the spread of antimicrobial resistance.
[Antimicrobial stewardship]
Proper use of antimicrobials is essential in healthcare.
What is the impact of medical interventions on host defenses?
They can disrupt defenses, increasing host susceptibility to infection
Examples include surgeries, use of catheters, and immunosuppressive treatments.
What are the two main types of immune responses?
- Innate (non-specific)
- Adaptive (specific)
Both types play critical roles in defense against infections.
True or False: Virulence factors are static and do not evolve.
False
Virulence factors are always evolving, which poses challenges for treatment and prevention.
What is the equation that represents infection?
VIRULENT MICROBE + SUSCEPTIBLE HOST = INFECTION
Define microbial virulence.
Measure of pathogenicity in a susceptible host.
What is a pathogen?
Microbe that can cause infection.
What does pathogenicity refer to?
Ability of a microbe to cause infection.
