Questions and Answers
Which of the following assumptions about infection is false?
Identify the sterile (microbe-free) anatomical site from the list below.
Place the following occurrences in the proper sequence or order.
Microbial antagonism means that
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Resident biota (normal flora) of human beings include members of the
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Infants are typically first exposed to disease
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Host defenses are NOT compromised by
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Endogenous infections are caused by
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Bacteria colonizing the body are necessary for proper development. A germ-free animal displays
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A virulence factor is one which
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Which of the following is NOT an adhesion mechanism that bacteria use to attach to a host?
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Antiphagocytic factors produced by microorganisms include all of the following EXCEPT
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Microbial infection damages hosts by
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Exotoxins differ from endotoxins in that exotoxins
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A focal infection is where the infectious agent
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Objective evidence of disease as noted by an observer is called
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Identify which is a symptom from the list of signs below.
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After initial infection, some infectious agents go into a dormancy, or ________, but may re-emerge to produce a recurrent disease state.
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When cases are concentrated in one area at a relatively stable rate, then the disease is
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_______________ transmission means the disease is spread through a population from one infected individual to another.
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______ are individuals who inconspicuously shelter a pathogen and spread it to others.
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A fomite is _________ that can transmit disease.
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An infection which is indigenous to animals but can be transmitted to humans is a _________ infection.
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Koch's Postulates for identifying a pathogen require all of the following EXCEPT
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Universal (Blood and Body Fluid) Precautions include
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As the infectious dose of the microorganism increases, the virulence of the microorganism increases.
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Most pathogens have one preferred portal of entry.
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Exotoxins and endotoxins differ in their site of effect.
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-itis means 'inflammation,' for example, gastritis is an inflamed intestine.
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Most colonization events result in infection and disease.
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Infections which come on quickly with severe symptoms are termed 'chronic' infections.
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Mortality rate measures the number of people with infections. Morbidity rate measures the number of deaths in a population.
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Epidemiology is the study of disease in individuals.
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Nosocomial infections are acquired in a hospital from surgical procedures, equipment, personnel, and often involve drug-resistant microorganisms.
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There are no microorganisms that can cross the transplacental barrier, so fetuses are protected until birth.
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Study Notes
Infection and Host Interaction
- Infection requires pathogens to penetrate host defenses, enter tissues, and multiply; they do not have to be opportunistic.
- Sterile anatomical sites in the body include the bladder, which is free from microbes.
Sequence of Infection
- Infection typically follows the order: contact → infection → disease.
Microbial Antagonism
- Microbial antagonism occurs when beneficial microbes prevent pathogenic invasion.
Normal Flora
- Human resident biota (normal flora) includes bacteria, fungi, and potentially harmful arthropods.
Infant Exposure
- Infants are first exposed to diseases during the birth process.
Host Defenses
- Host defenses can be compromised by diseases, chemotherapy, and surgery, but not by simply being middle-aged.
Endogenous Infections
- These infections occur when normal biota enter unusual body sites.
Germ-Free Animals
- Germ-free animals demonstrate heightened sensitivity to pathogens due to lack of microbial colonization.
Virulence Factors
- Virulence factors assist pathogens in invading and establishing infection within the host.
Bacterial Adhesion Mechanisms
- Common adhesion mechanisms include fimbriae, glycocalyx, and dextran slime; however, envelope spikes are not an adhesion mechanism.
Antiphagocytic Factors
- Antiphagocytic components include leukocidins and capsules, but erythrocytes do not serve this purpose.
Infection Damage Mechanisms
- Bacterial infections damage hosts through toxins, exoenzymes, and immune response induction.
Toxin Variations
- Exotoxins are secreted from living cells, unlike endotoxins, which are composed of lipopolysaccharides and are less stable.
Focal Infections
- A focal infection involves the infectious agent spreading from an initial site to other tissues.
Disease Indicators
- Signs are objective evidence of disease, while symptoms are subjective experiences reported by the patient.
Dormant Infectious Agents
- Some pathogens can remain dormant (latency) after initial infection and may later cause disease.
Disease Epidemiology
- A disease is considered endemic when its cases are stable in a specific area.
Disease Transmission
- Horizontal transmission refers to the spread of disease from one infected individual to another.
Carriers
- Carriers are individuals who harbor pathogens without exhibiting symptoms but can spread the disease.
Fomites
- Fomites are inanimate objects that can transmit diseases.
Zoonotic Infections
- Zoonotic infections originate from animals and can be transmitted to humans.
Koch's Postulates
- To identify a pathogen, Koch's Postulates require re-inoculation and isolation; DNA sequencing is not a necessity.
Infection Control
- Universal precautions involve using barriers, safely disposing of sharps, and immediate decontamination of soiled items.
Pathogen Virulence and Infection Rates
- Increased infectious doses do not necessarily correlate with increased virulence; most pathogens often have a preferred entry point.
Toxin Sites of Effect
- Exotoxins and endotoxins differ in their sites of action within the host.
Inflammation Terminology
- The suffix "-itis" indicates inflammation, such as in gastritis for inflamed stomach lining.
Colonization and Disease
- Not all colonization leads to infection or disease; hence most events do not result in illness.
Infection Characteristics
- Acute infections manifest rapidly with severe symptoms; chronic infections develop gradually.
Measuring Disease Impact
- Mortality rate indicates deaths in a population; morbidity rate tracks the number of infected individuals.
- Epidemiology focuses on disease patterns in populations, not individuals.
Nosocomial Infections
- Nosocomial infections are acquired in healthcare settings and are often caused by drug-resistant pathogens.
Placental Barrier
- Microorganisms can cross the transplacental barrier; fetuses are not completely protected from infection.
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Test your knowledge with these flashcards from Microbiology Chapter 11. Each card presents key concepts and questions related to the conditions for infection and sterile anatomical sites. Perfect for review and exam preparation on microbiological principles.