Microbial Methods of Pathogenicity (Lecture 11) Flashcards
What is the human microbiome?
The sum total of all microbes found in and on a normal human
Intimate contact between microbes and humans; humans have 21k proteins while microbes have 8 million
Define colonization in the context of microbiology.
Microbes living on us
What occurs during an infection?
Microbe gets past host defenses, enters tissues, and multiplies
What is a disease?
Any deviation from healthy (e.g., age) that damages or disrupts tissues and organs with microbes
Differentiate between pathogenicity and virulence.
Pathogenicity is an organism’s potential to cause disease; virulence is the relative severity of the disease
What are true pathogens?
Organisms that cause disease in healthy people
What are opportunistic pathogens?
Organisms that cause disease when defenses are compromised
What is a virulence factor?
Virulence is how strong or harmful a germ (like a bacteria, virus, or parasite) is at making you sick.
What are polymicrobial infections?
Infections that have multiple contributions from different microorganisms
List the portals of entry for pathogens.
- Skin
- Mucous membranes
- Gastrointestinal tract
- Respiratory tract
- Urogenital tract
What is a localized infection?
Microbes enter the body and remain confined to a specific tissue
What is a systemic infection?
Infection spreads to several sites and tissue fluids, usually via the bloodstream
What is a focal infection?
Infectious agent spreads from a local site to other tissues
What is a mixed infection?
Several agents establish themselves simultaneously at the infection site
What is a primary infection?
The initial infection
What is a secondary infection?
A second infection caused by a different microbe, complicating a primary infection
What is the difference between acute and chronic infections?
- Acute: Rapid onset with severe but short-lived effects
- Chronic: Progresses and persists over a long period
How do microbes damage tissue?
- Directly through enzymes or toxins
- Indirectly by causing excessive host defense responses
- Through epigenetic changes
What are exotoxins?
Proteins with high specificity to target cells that can damage cell membranes
Think of them as poisons made and released by certain bacteria that can cause damage to your body—even if the bacteria itself isn’t inside you anymore.
What is an endotoxin?
A lipopolysaccharide (toxin) found in the outer layer of certain bacteria (specifically Gram-negative ones).
They stay inside the bacteria until it dies—then they get released and can cause things like fever or inflammation in your body.
Define sign in the context of disease.
Objective evidence of a disease observed by an observer
Define symptom in the context of disease.
Subjective evidence of disease as sensed by a patient
What is a syndrome?
Disease identification by signs and symptoms
What are the stages of an infection?
- Incubation
- Prodromal
- Acute phase
- Convalescence
- Continuation phase
