Unit5: Ch 10 (Porth's 5th Ed) - Mechanisms of Infectious Disease

Question 1

1. Staphylococcus aureus commonly found in the skin, nares, and other body sites of
   patients without any signs and symptoms of infection is known as which of the
   following conditions listed below?
   A) An opportunistic infection
   B) A parasitic infestation
   C) Bacterial colonization
   D) A saprophytic infection

Answer 1

Ans: C
Feedback:
The ongoing presence of bacteria in the body that do not cause infection is called
colonization. Opportunistic infection by ordinarily nonpathogenic organisms can occur
in immunosuppressed hosts. Parasitism is a condition in which the organism exists at the
expense of, and without benefiting, the host. Saprophytes do not cause infection.

Question 2

2. Which of the following statements is an accurate descriptor of the role of viruses in
   human infections?
   A) Viruses have no genetic material of their own.
   B) Some viruses are capable of transforming normal host cells into malignant cells.
   C) Viruses are often implicated in cases of transmissible neurodegenerative diseases.
   D) Viruses require stimulation after a latent period before they are able to produce
   symptoms.

Answer 2

Ans: B
Feedback:
Viruses that are categorized as oncogenic are able to induce malignancy in host cells.
Viruses have limited genetic material (either RNA or DNA), but no virus lacks genetic
material. Transmissible neurodegenerative disease is associated with prions. Not all
viruses include a latent period.

Question 3

3. Which of the following types of pneumonia listed below is best characterized by an
   infective agent that produces sputum samples with a peptidoglycan cell wall, expresses
   endotoxins, replicates readily in broth and on agar, grows in clusters, has pili, and does
   not stain when exposed to crystal violet?
   A) Chlamydial
   B) Viral
   C) Mycoplasmal
   D) Bacterial

Answer 3

Ans: D
Feedback:
Although chlamydiae, viruses, and mycoplasmas all can cause pneumonia, only bacteria
have all of these characteristics. Chlamydiae and viruses are obligate intracellular
organisms and therefore would grow only in cell culture, and mycoplasmas lack the
peptidoglycan cell wall typical of bacteria.

Question 4

4. The nurse will most likely assess which of the following clinical manifestations in a
   client who was diagnosed with Creutzfeldt-Jakob disease?
   A) Change in behavior and memory and loss of coordination leading to
   encephalopathy
   B) Gastrointestinal problems like vomiting and diarrhea
   C) Muscle inflammation and edema, making movements very painful
   D) Projectile vomiting, hypertension, and drowsiness caused by elevated ICP

Answer 4

Ans: A
Feedback:
Creutzfeldt-Jakob disease is collectively called transmissible neurodegenerative disease
that is characterized by a slowly progressive, noninflammatory neuronal degeneration
and leads to a loss of coordination, dementia, and death. With this disease,
encephalopathy is the primary presenting factor. GI problems, muscle inflammation,
and ICP are not clinical manifestations associated with this prion.

Question 5

5. The spirochete leptospires is primarily transmitted to farmers by
   A) an airborne mechanism.
   B) exposure to spores in the environment.
   C) direct contact with infected animals.
   D) a mosquito bite.

Answer 5

Ans: C
Feedback:
The pathogenic leptospires inNfeUctRaSwIiNdeGvTaBri.etCyOofMwild and domestic animals. Infected
animals shed the organisms into the environment through the urinary tract. Transmission
to humans occurs by contact with infected animals or urine-contaminated surroundings.
This spirochete is not transmitted by air, spores, or a fomite.

Question 6

6. The nurse knows which of the following statements best describes the characteristic trait
   of risckettsiae related to Rocky Mountain spotted fever? Rickettsiae
   A) are eukaryotic.
   B) have both RNA and DNA.
   C) have a distinct spiral-shaped morphology.
   D) are neither gram negative nor gram positive.

Answer 6

Ans: B
Feedback:
Rickettsiae combine characteristics of bacteria and viruses. Rickettsiae are prokaryotic
but not spiral shaped. Rickettsiae are able to be classified by Gram stain like other
microorganisms

Question 7

7. An 81-year-old female patient in a subacute medical unit of a hospital has developed an
   oral Candida albicans infection. Which of the following phenomena would the patient’s
   nurse suspect as a key contributing factor to her infection?
   A) The moist and temperature-suited oral environment of the client’s mouth
   B) The ability of fungi to remain latent until the host reaches an
   immunocompromised state
   C) Antibiotic therapy that eliminated normal bacterial flora
   D) The airborne communicability of yeast and molds and subsequent inhalation

Answer 7

Ans: C
Feedback:
Elimination of bacterial flora that normally keeps colonizing fungi in check can induce
the proliferation of fungi. The environment of the client’s mouth provides a conducive
environment but with an intact immune system is rarely a direct contributor to
colonization. Latency is not a common trait of Candida albicans, and airborne
transmission is not likely to be a causative factor.

Question 8

8. The nurse knows which of the following statements below is appropriate to be included
   in an education session for a 21-year-old male with a diagnosis of malaria?
   A) “Your infection likely began with the introduction of fertilized protozoal ova from
   a mosquito.”
   B) “The protozoa responsible have hijacked the genetic material of your cells in
   order to reproduce.”
   C) “You are very tired the pathogens are utilizing the ATP that your own
   cells need.”
   D) “The infectious organisms are considered tiny, single-celled animals, given their
   complete eukaryotic machinery.”

Answer 8

Ans: D
Feedback:
Protozoa possess full eukaryotic machinery including organelles and a nucleus. Ova are
associated with helminthes, and protozoa do not utilize the host’s genetic material for
reproduction. Appropriation of ATP is associated with chlamydiae.

Question 9

9. The physician knows the client G1P0 has correctly understood the prenatal education
   regarding sexually transmitted infection as evidenced by which of the following
   statements listed below?
   A) “Gonorrhea and chlamydia out of the various infectious agents pose the greatest
   risks of transmission from mother to child.”
   B) “I know that my baby will need observation for HIV signs and symptoms in the
   weeks following my delivery.”
   C) “My baby could become infected either across the placenta or during the birth
   itself.”
   D) “If I receive prophylactic immunization, I will reduce my baby’s chance of being
   born with an illness.”

Answer 9

Ans: C
Feedback:
Vertical transmission may occur across the placenta in utero or during the birth event
itself. Cytomegalovirus and HIV infections are the most common congenital infections.
HIV signs and symptoms are not immediately apparent in the infant. Prophylactic
immunization is not noted as a proven intervention for preventing vertical transmission

Question 10

10. Which of the following procedures reduces the potential for infection primarily by
    addressing the portal of entry?
    A) Wiping down common areas with buffered bleach on a regular basis
    B) Wearing gloves when contact with blood or body fluids is anticipated
    C) Disposing of soiled clothing and bed linens in a dedicated receptacle
    D) Isolating patients who have antibiotic-resistant infections

Answer 10

Ans: B
Feedback:
Wearing gloves specifically blocks the portal of entry to the health care worker through
the use of a physical barrier. Bleaching and cleaning, as well as disposing of soiled
linen, eliminate the source of infection by killing microorganisms, and isolating patients
similarly addresses a source by minimizing contact with uninfected persons.

Question 11

11. A school-age child with a history of asthma has brought a note home from school
    stating that there has been one case of meningitis (Neisseria meningitides) in the school.
    Since the mother is a nurse, she is very concerned since she knows the portal of entry of
    this pathogen is
    A) by inhalation via the respiratory tract such as through breathing or yawning.
    B) by direct contact with a contaminated object such as a pencil.
    C) by ingestion such as when children share their drink with their friends.
    D) through a cut or abrasion that may occur on the playground.

Answer 11

Ans: A
Feedback:
Neisseria meningitides is one of a number of pathogens that invade the body through the
respiratory tract.

Question 12

12. Which of the following scenarios best describes an example of infection originating
    with a fomite?
    A) A client who contracted hepatitis C through sharing a contaminated syringe with
    an infected person
    B) A nurse with a positive tuberculin screening test (PPD) after admitting a patient
    diagnosed with tuberculosis (TB)
    C) A woman who contracted Lyme disease after a tick bite
    D) A man who has been diagnosed with trichinosis after eating undercooked pork

Answer 12

Ans: A
Feedback:
An object that carries an infectious organism, such as a dirty syringe, is known as a
fomite. Airborne contact with TB does not utilize a fomite. An infection via contact with
an infected arthropod constitutes zoonosis. A person who consumes ova in undercooked
meat acquires an infection by ingestion.

Question 13

13. The nurse knows which of the following statements listed below best matches the phase
    of the infectious process of food poisoning with a client with sudden, violent diarrhea
    and vomiting after consuming chicken and potato salad 8 hours ago at the beach on a
    hot day?
    A) Maximum impact of infectious process
    B) Insidious prodromal phase
    C) Sudden incubation of of active replication
    D) Subacute prodromal phase

Answer 13

Ans: A
Feedback:
The lack of prodrome and intense symptom onset typify a fulminant illness. The onset
described does not characterize a prodromal phase or incubation.

Question 14

14. Which of the following infectious agents listed below would be a site-specific pathogen
    and not spread throughout the body via the circulatory system? A patient diagnosed with
    A) B. burgdorferi caused by a tick bite.
    B) Salmonella typhi related to ingestion of contaminated food or water.
    C) Helicobacter pylori diagnosed after an endoscopic procedure.
    D) N. meningitidis infection in a child in a daycare setting.

Answer 14

Feedback:
H. pylori is an extreme example of a site-specific pathogen (localized infectious
disease). The other three pathogens are called systemic pathogens because they can
disseminate throughout the body via the circulatory system.

Question 15

15. A family consumed some undercooked hamburger at a picnic and has since developed
    bloody diarrhea. The nurse knows which of the following statements listed below is
    correct regarding the infectious process?
    A) Evasive factors that become more virulent by evading parts of the host’s immune
    system
    B) Exotoxins that damage vascular endothelium causing bleeding and low platelet
    counts
    C) Adhesion factors that can anchor a pathogen firmly to the host tissue surfaces
    D) Invasive factors capable of destroying the cell membrane by utilization of
    enzymes

Answer 15

Ans: B
Feedback:
Exotoxins can allow organisms to produce hemorrhagic colitis, which can be fatal. It is
characterized by vascular endothelial damage, acute RF, and thrombocytopenia (low
platelet counts). Toxic cell walls are classified as endotoxins. The ability to survive
immune responses characterizes evasive factors. Adhesion factors and invasive factors
are not involved in this situation.

Question 16

16. A patient diagnosed with H pylori asks the nurse, “How an infection can occur in the
    stomach since it is an acid environment?” The nurse responds,
    A) “We have many infectious agents that can live in an acidic environment with a pH
    more than 8.0.”
    B) “H. pylori is a virus and is still being researched as to how it is able to survive in
    the stomach acids.”
    C) “H. pylori produces an enzyme called urease that converts gastric juices into
    ammonia, which neutralizes the acidic stomach environment.”
    D) “This parasite secretes an enzyme called coagulase, which protects the pathogen
    from the antibodies.”

Answer 16

Ans: C
Feedback:
H. pylori, the infectious cause of gastritis and gastric ulcers, produces the urease enzyme
on the outer cell wall. The urease converts gastric urea into ammonia, thus neutralizing
the acidic environment of the stomach and allowing the organism to survive in this
hostile environment.

Question 17

17. A client has a suspected infection by a particular microorganism in question that cannot
    be cultured. Which of the following processes listed below is most likely to result in an
    accurate diagnosis for the client?
    A) Observe directly for the presence or absence of specific antigens in the client’s
    blood serum sample.
    B) Introduce cultured, marked antibodies to the client, and observe for a reaction
    with antigens in the client.
    C) Observe for a cytopathic effect on biopsy tissue samples from the client’s mucosa.
    D) Release purified antigens into the client’s circulation to observe whether the client
    has produced the relevant antibodies

Answer 17

Ans: B
Feedback:
The process described is direct antigen detection, which can indirectly implicate a
microorganism that is unable to be cultured. Answer D describes the same process in
reverse, while answers A and C do not describe existing diagnostic processes.

Question 18

18. A client has been diagnosed with herpes simplex virus. The client states that, “modern
    medicine produces more and more antivirals every year, and so the treatment should be
    simple.”Which of the following statements listed below is the best response?
    A) “The recent rise of drug resistance has significantly hampered the elimination of
    viruses.”
    B) “The cell coat of viruses is particularly resilient to the available synthetic
    antivirals.”
    C) “The use of antivirals is severely limited by the unwanted adverse effects that they
    cause.”
    D) “Treatment options for viruses are often limited because what destroys viruses
    often damages your own body cells.”

Answer 18

Ans: D
Feedback:
Viruses are difficult to treat because interference with their replication often requires
interference with the body’s cell replication processes. Although they do exist with
antiviral treatments, drug resistance and side effects are phenomena more closely
associated with antibacterials. Antivirals act upon DNA or RNA synthesis, not the cell
wall.

Question 19

19. A client with a diagnosis of sepsis has received intravenous immune globulin (IVIG) as
    a partial treatment. The nurse knows which of the following client responses listed
    below would best suggest an accurate understanding of IVIG treatment?
    A) “These antibodies in the solution have been collected from individuals who have
    successfully fought off the same infection.”
    B) “The IVIG should help stimulate fever, inflammation, and tissue repair in the fight
    against the infection.”
    C) “A big part of my IVIG treatment is actually stimulating and supplementing my
    immune system to do the work itself.”
    D) “The main effect of IVIG is to cause my body to produce more white blood cells
    to fight infection.”

Answer 19

Ans: C
Feedback:
IVIG involves infusion of pooled antibodies that supplement and stimulate the client’s
immune system to respond above and beyond its own capacities. It is not collected from
individuals who have had similar infections. The primary effect of IVIG is not white
blood cell production. Stimulation of fever, inflammation, and tissue repair are more
closely associated with cytokine therapy.

Question 20

20. The nurse in the emergency department knows that clients exposed to Clostridium
    botulinum, an agent of bioterrorism, would likely be exhibiting which of the following
    clinical manifestations listed below?
    A) Blindness and respiratory distress
    B) Hemorrhage from all orifices resulting in signs of shock and coma
    C) Frothy, odiferous diarrhea and dehydration
    D) Muscle weakness in extremities eventually leading to paralysis of respiratory
    muscles

Answer 20

Ans: D
Feedback:
Clostridium botulinum causes neuromuscular paralysis and is listed as a category A
agent.

Question 21

21. Health care team members know recently that an increased incidence of infections such
    as West Nile virus and SARS does not match with previously established patterns.
    Which of the following phenomena constitutes the most significant contributor to the
    spread of new diseases in the United States?
    A) Drug resistance by bacterial and protozoal infections
    B) Increased ease and frequency of individual and group international travel
    C) Genetic variation and mutation by microorganisms
    D) Decreased living standards and public health standards in urban areas

Answer 21

Ans: B
Feedback:
While drug resistance, lapses in public health, and genetic variation are all contributing
factors in incidents of infection, the increase in new and global diseases is primarily
attributed to the ease and frequency of individual and group international travel.