EW Microb 3 – Flashcards
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A patient acquires an infection by touching a contaminated door handle. Which mode of transmission best describes this scenario?
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indirect contact transmission
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A dog develops a diarrheal disease after drinking water from a creek during a hike with his owner. Which of the following best describes this method of disease transmission?
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vehicle transmission
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Plague is transmitted through the bite of an infected flea. Which of the following best describes this mode of transmission?
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vector transmission
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According to the animation, surgical infections account for what percentage of nosocomial infections?
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20%
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What type of nosocomial infection is likely to arise from intravenous catheterizations?
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Bacteremia
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How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?
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Antibiotics can be used in aerosols, thereby entering the environment.
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Why are invasive procedures likely to increase the risk of nosocomial infections?
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These procedures allow microbes from the skin to enter the bloodstream of the patient.
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How can health care workers reduce the occurrence of nosocomial infections?
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Practice more stringent aseptic techniques
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The health of the patient
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should be the primary concern of the healthcare worker.
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How can surgeons help to limit nosocomial infections?
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They should perform surgeries and invasive procedures only when absolutely necessary.
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If a patient notices a healthcare worker not following suggested precautions,
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they should immediately bring it to the attention of the healthcare worker.
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Which of the following characteristics of a catheter should be considered, to help minimize the spread of nosocomial infections?
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Single-use
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Which of the following statements is true regarding hand washing?
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Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction
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Expected prevalence of a disease is
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the expected occurrence of a disease based on past observations
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In the sixth segment of the animation, why is the disease epidemic in North America?
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The disease occurs at a higher rate than what would normally be expected in this region.
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In the last segment of the animation, how many regions of the world experience the pandemic during April of year four? Hint 1. A pandemic occurs when a disease is epidemic on more than one continent at the same time.
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Five
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In the last segment of the animation, when does the first epidemic occur?
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January of year three
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If a disease occurs at a fairly stable rate, it is said to be
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endemic
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Epidemiology is defined as the study of
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where and when a disease occurs, and how it is transmitted.
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What is the role of epidemiology?
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To learn how to treat and prevent various diseases.
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The major significance of Robert Koch's work is that
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microorganisms cause disease.
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Which of the following is NOT a verified exception in the use of Kochs postulates?
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Some diseases are noncommunicable.
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Which of the following diseases is NOT spread by droplet infection?
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botulism
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Biological transmission differs from mechanical transmission in that biological transmission
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involves specific diseases.
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Which of the following definitions is INCORRECT?
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epidemic: a disease that is endemic across the world
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Focal infections initially start out as
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local infections.
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The rise in herd immunity amongst a population can directly attributed to
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vaccinations
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Which of the following is NOT a reservoir of infection?
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None of the answers is correct; all of these can be reservoirs of infection.
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Which of the following is NOT a communicable diseases?
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tetanus
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Which of the following is a fomite?
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a hypodermic needle
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Symptoms of disease differ from signs of disease in that symptoms
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are changes felt by the patient.
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hich of the following definitions is INCORRECT?
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secondary infection: a long-lasting illness
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Which of the following pairs is mismatched?
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None of the pairs is mismatched.
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Which of the following can contribute to postoperative infections?
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All of the answers are correct.
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The CDC is located in
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Atlanta, GA.
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In which of the following diseases can gender be considered a viable predisposing factor?
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urinary tract infections
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In which of the following patterns of disease does the patient experience no signs or symptoms?
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incubation and convalescence
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During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.
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a zoonosis.
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Compromised hosts are always suffering from suppressed immune systems.
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False
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Urinary tract infections are the most common forms of nosocomial infections.
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True
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What do hyaluronidase and kinase have in common?
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They are both enzymes involved in evading host defense.
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According to your Concept Map, which of the following organisms exhibits antigenic variation?
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N. gonorrheae
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Which of the following virulence factors could directly prevent phagocytosis and/or phagocytic degradation?
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all of the above
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Endotoxins are also known as
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Lipid A
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When would endotoxins be released from a bacterial cell?
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When the cell dies
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Which of the following would be the first sign of an infection that resulted in the release of endotoxin?
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Fever
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Why is a release of endotoxin into the bloodstream potentially deadly?
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It can lower blood pressure and cause the patient to go into shock.
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An exotoxin that has the ability to kill or damage host cells is referred to as a(n)
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cytotoxin
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Which domain of the A-B toxin binds to cell surface receptors on the host cell?
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B domain
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How are superantigens different from other types of exotoxins?
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Superantigens cause an overstimulation of the host immune system.
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A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n)
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superantigen
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A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n)
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neurotoxin
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How are immune cells able to detect foreign pathogens?
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They are able to detect structures on the surfaces of foreign cells that are not found in the host.
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How does a capsule help certain bacteria evade detection by the immune system?
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The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.
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Which of the following microorganisms actually grows inside the macrophage?
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Tuberculosis bacterium
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How does the protozoan Trypanosoma evade detection by the immune system?
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It can change the surface antigens frequently, preventing the immune system from tracking it.
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Certain traits that allow pathogens to create infection and cause disease are termed
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virulence factors.
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Which of the following enzymes breaks down the "glue" that holds cells together?
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Hyaluronidase
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Which of the following virulence factors would be found in Staphylococcus aureus?
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Staphylokinase
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How do fibrinolysins enhance a pathogen's virulence?
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They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.
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The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the hosts antibodies is called
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antigenic variation.
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The ID50 is
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the dose that will cause an infection in 50 percent of the test population.
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Which of the following statements is FALSE?
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Coagulase destroys blood clots.
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Which of the following is NOT a membrane-disrupting toxin?
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A-B toxin
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Which of the following does NOT contribute to the symptoms of a fungal disease?
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cell walls
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All of the following are used by bacteria to attach to host cells EXCEPT
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A-B toxins.
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Twenty-five people developed symptoms of nausea, vomiting, and diarrhea three to six hours after attending a church picnic where they ate a ham and green bean casserole with cream sauce. The most likely cause of this case of food intoxication is
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erythrogenic toxin.
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Which of the following statements about M protein is FALSE?
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It is readily digested by phagocytes.
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Bacteria such as E. coli and Salmonella produce invasins that bind host cells, thus causing the cells to
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engulf the bacteria.
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Endotoxins in sterile injectable drugs could cause
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septic shock symptoms.
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Which of the following is NOT a cytopathic effect of viruses?
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toxin production
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the table shows the ID50 for Staphylococcus aureus in wounds with and without the administration of ampicillin before surgery. Based on the data, the administration of ampicillin before surgery
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decreases the risk of staphylococcal infection.
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Biofilms provide pathogens with an adhesion mechanism and aid in resistance to antimicrobial agents.
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True
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Many pathogens use the same portal for entry and exit from the body.
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True
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Gram positive Cocci
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Streptococci, II) Staphylococcus
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1) Strings of round cells 2) Characterized by how the cells grow on blood agar
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Streptococci
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cause a green opaque color change
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hemolytic streptococci
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-lyse RBC's to form clear areas.
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Beta hemolytic streptococci
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are subdivided into strains based on cell wall polysaccharide antigens.
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Beta hemolytic streptococci
