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Questions and Answers
Which of the following are examples of virulence factors that can help a pathogen escape detection or removal by the immune system?
Which of the following are examples of virulence factors that can help a pathogen escape detection or removal by the immune system?
What is the term for a disease that is constantly present in a population or in a certain geographical region?
What is the term for a disease that is constantly present in a population or in a certain geographical region?
The term "syndrome" refers to a single, isolated symptom.
The term "syndrome" refers to a single, isolated symptom.
False
A ______ is an individual who harbors pathogens and spreads them to others, even if they don't show symptoms.
A ______ is an individual who harbors pathogens and spreads them to others, even if they don't show symptoms.
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What is the name of the toxin produced by Corynebacterium diphtheriae that interferes with protein synthesis by blocking an elongation factor?
What is the name of the toxin produced by Corynebacterium diphtheriae that interferes with protein synthesis by blocking an elongation factor?
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Which of the following is a common symptom of Staphylococcus aureus food poisoning?
Which of the following is a common symptom of Staphylococcus aureus food poisoning?
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What are the two main clinical manifestations of the plague, caused by Yersinia pestis?
What are the two main clinical manifestations of the plague, caused by Yersinia pestis?
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What is the name of the rash often seen in patients with Lyme disease, caused by Borrelia burgdorferi?
What is the name of the rash often seen in patients with Lyme disease, caused by Borrelia burgdorferi?
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Malaria is a bacterial infection transmitted by mosquitoes.
Malaria is a bacterial infection transmitted by mosquitoes.
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What are the two forms of vectors in the transmission of diseases?
What are the two forms of vectors in the transmission of diseases?
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Which of the following are portals of exit for pathogens from the human body?
Which of the following are portals of exit for pathogens from the human body?
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What are the two types of infections acquired in healthcare facilities?
What are the two types of infections acquired in healthcare facilities?
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Study Notes
Microbe/Host Relationships
-
Terminology:
- Symbiosis: Living together
- Mutualism: Both benefit
- Commensalism: One benefits, the other is unaffected
- Parasitism: One benefits, the other is harmed
- Pathogen: Organism that causes disease
-
Normal Microbiota (Normal Flora):
- Indigenous microorganisms
- Can become harmful in unusual circumstances
- Factors: Introduction into abnormal sites, immune suppression, elimination of microbial antagonism
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Opportunistic Pathogens:
- Normal flora that cause harm in certain situations
- Require a chance or opportunity to cause disease
Infectious/Disease Processes
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Infection:
- Growth of microorganisms in host
- Does not always lead to disease
-
Disease:
- Significant injury to body, hindering regular functioning
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Reservoirs of Infection:
- Animal Reservoirs: Animals carry pathogens
- Human Carriers: Individuals harboring pathogens
- Nonliving Reservoirs: Environments that harbor pathogens.
-
Stages of Infection:
- Entry
- Adhesion (binding to surface)
- Colonization and Growth (survive and spread)
Manifestations of Disease
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Symptoms:
- Subjective characteristics (felt by patient)
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Signs:
- Objective characteristics (observed by others)
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Syndromes:
- Combination of symptoms and signs characterizing a disease
Virulence Factors of Infectious Agents
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Extracellular Enzymes:
- Breakdown tissues
- Examples: Collagenase, Hyaluronidase, Coagulase, Kinases
Folliculitis
- Usually caused by Staphylococcus aureus (gram-positive coccus)
- Highly resistant to drying
- Spread by contact with infected individuals or fomites.
- Infection of hair follicle.
Toxins
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Exotoxins:
- Proteins released by some bacteria
- Highly toxic
- Specific target cells (e.g., neurotoxins, enterotoxins, nephrotoxins)
- Can be inactivated into toxoids for immunization
Staphylococcal Diseases
-
Scalded Skin Syndrome:
- Exfoliative toxin causes skin to peel off
-
Food Poisoning:
- Heat-stable enterotoxin causes nausea, vomiting, diarrhea
-
Toxic Shock Syndrome:
- Toxin release causing fever, low blood pressure
Scarlet Fever
- Caused by lysogenized strains of Streptococcus pyogenes
- Gram positive, catalase negative coccus
Diphtheria
- Caused by lysogenized strains of Corynebacterium diphtheriae
- Gram positive pleomorphic rods
- Diphtheria toxin interferes with protein synthesis
Pertussis/Whooping Cough
- Caused by Bordetella pertussis
- Gram-negative coccobacillus
- Initial symptoms resemble common cold
- Recurrent, violent coughing
Cholera
- Caused by Vibrio cholerae
- Gram-negative, curved rod
- Endemic in areas with poor sanitation
- "Rice-water stool" - major symptom
Rocky Mountain Spotted Fever
- Caused by Rickettsia rickettsii
- Gram-negative rod-shaped intracellular parasite
- Transmitted by various species of ticks
- Fever, chills, headache, and muscular pain followed by rash.
Plague
- Caused by Yersinia pestis
- Gram negative rod
- Endemic in rodents, spread to humans by flea bite
- Bubonic Plague and Pneumonic Plague
Lyme Disease
- Caused by Borellia burgdorferi
- Gram negative spirochete
- Most prevalent tick-borne disease in the U.S.
- "Bull's-eye" rash, may progress to chronic symptoms
Malaria
- Caused by Plasmodium protozoa
- Endemic in areas with mosquito breeding sites
- Characterized by recurrent fever, chills, and other symptoms
Epidemiology
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Study of incidence, frequency and transmission of disease
-
Definitions:
- Incidence: Number of new cases
- Prevalence: Total number of cases
- Endemic: Constantly present disease
- Sporadic: Occurs infrequently
- Epidemic: Outbreak in a particular population
- Pandemic: Worldwide outbreak
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Healthcare-Associated Infections (Noscomial Infections):
- Exogenous: Acquired from environment
- Endogenous: Normal flora
- Iatrogenic: Resulting from treatment
- Superinfections: Result of antimicrobial treatment
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Description
Test your knowledge on microbe/host relationships, including terminologies such as symbiosis, mutualism, and pathogenicity. This quiz covers the roles of normal microbiota and opportunistic pathogens in infectious diseases. Enhance your understanding of infection and disease processes through these concepts.
