Microbial Mechanisms Of Pathogenicity Chapter.15 Exam Prep

Chapter 15: Microbial Mechanisms of Pathogenicity

= Correct answer

Multiple Choice

1. Which of the following would be considered a symptom?

A. blood pressure reading of 150/90 mm Hg

B. body ache and chills

C. fever of 39 °C

D. heart rate of 120 bpm

Difficulty: Easy

ASM Standard: N/A

1. Which of the following would be considered a sign?

A. blurry vision

B. body ache and chills

C. burning sensation during urination

D. gross hematuria (visible presence of blood in urine)

Difficulty: Easy

ASM Standard: N/A

1. Which of the following is an example of a nosocomial disease?

A. acquiring Giardia while drinking from a stream during a camping trip

B. acquiring Listeria after eating at a public restaurant

C. acquiring MRSA after touching a locker door handle after an already infected individual did so

D. obtaining a Pseudomonas respiratory infection during a recent visit to the hospital

Difficulty: Easy

ASM Standard: 23

1. Sickle cell anemia can be classified as which type of disease?

A. idiopathic

B. infectious, communicable

C. infectious, noncommunicable

D. noninfectious

Difficulty: Easy

ASM Standard: N/A

1. Which of the following is not a zoonotic disease?

A. rabies

B. Rocky Mountain spotted fever

C. typhoid

D. yellow fever

Difficulty: Easy

ASM Standard: 23

1. What period of disease describes when the patient begins to feel general signs and symptoms?

A. incubation period

B. period of convalescence

C. period of illness

D. prodromal period

Difficulty: Easy

ASM Standard: 23

1. During which period of disease is a patient most susceptible to developing a secondary infection?

A. incubation period

B. period of convalescence

C. period of decline

D. prodromal period

Difficulty: Moderate

ASM Standard: 23

Examine the graph shown below and then answer questions 8 and 9.

1. Examine the graph and determine the approximate ID₅₀ of the virus.

A. 10 particles

B. 5000 particles

C. 13,000 particles

D. cannot be determined from the data collected

Difficulty: Moderate

ASM Standard: 10, 23, 28b, 29, 36

1. Examine the graph and determine the LD₅₀ of the virus.

A. 10 particles

B. 5000 particles

C. 13,000 particles

D. cannot be determined from the data collected

Difficulty: Moderate

ASM Standard: 23, 28b, 29, 36

1. Identify which pathogen is the least virulent on the basis of ID₅₀.

A. pathogen A with an ID₅₀ of 1000 cells

B. pathogen B with an ID₅₀ of 50 cells

C. pathogen C with an ID₅₀ of 1 cell

D. pathogenicity cannot be determined from ID₅₀ values

Difficulty: Moderate

ASM Standard: 23

1. Which of the following is the definition of pathogenicity?

A. the ability of a microbial agent to cause disease

B. the ability of a microbial agent to cause infection

C. the ability of a microbial agent to prevent disease

D. the ability of a microbial agent to produce an antimicrobial compound

Difficulty: Easy

ASM Standard: 23

1. Which pathogen cannot pass the blood–placenta barrier and infect a fetus?

A. Herpes simplex virus 1

B. Listeria monocytogenes

C. Salmonella typhi

D. Toxoplasma gondii

Difficulty: Moderate

ASM Standard: 23

1. Which of the following is a common secondary fungal disease?

A. giardiasis

B. histoplasmosis

C. oral thrush

D. syphilis

Difficulty: Moderate

ASM Standard: 23

1. Which statement properly describes how Salmonella typhi enters host cells?

A. S. typhi binds to receptors on host cells that cause endocytosis.

B. S. typhi is not an intracellular pathogen.

C. S. typhi secretes effector proteins that cause membrane ruffling.

D. S. typhi specifically invades phagocytic host cells.

Difficulty: Difficult

ASM Standard: 8, 13, 22, 23

1. Why are Pseudomonas aeruginosa infections difficult to treat?

A. Because they are gram-positive bacteria, which are harder to treat.

B. Because they form biofilms, which are difficult for antibiotics to penetrate.

C. Because they have a special endotoxin that degrades many antibiotics.

D. Because we do not have any antibiotics that target P. aeruginosa.

Difficulty: Easy

ASM Standard: 13, 21, 22, 23

1. Which describes the condition in which blood contains actively dividing bacteria?

A. bacteremia

B. septicemia

C. toxemia

D. viremia

Difficulty: Easy

ASM Standard: 13, 23

1. Molecular Koch’s postulates are used to identify which characteristic of pathogens?

A. an effective treatment

B. the ID₅₀

C. the LD₅₀

D. virulence factor genes

Difficulty: Moderate

ASM Standard: 8, 23, 36

1. Hyaluronidase is which type of exoenzyme?

A. glycohydrolase

B. nuclease

C. phospholipase

D. protease

Difficulty: Easy

ASM Standard: 22, 23

1. Intracellular pathogens, like Listeria and Rickettsia, produce which type of exoenzyme to aid in escaping the phagosome?

A. glycohydrolases

B. nucleases

C. phospholipases

D. proteases

Difficulty: Moderate

ASM Standard: 13, 22, 23

1. Which virulence factor, produced by Staphylococcus aureus, allows the bacterium to be coated in fibrin that protects it from phagocytes?

A. catalase

B. coagulase

C. collagenase

D. oxidase

Difficulty: Moderate

ASM Standard: 13, 22, 23

1. What is the toxic component of endotoxin?

A. lipid A

B. the core oligosaccharide

C. the O-antigen

D. the peptidoglycan subunits

Difficulty: Easy

ASM Standard: 8

1. You are working in a hospital and have been asked to perform the LAL test (Limulus amebocyte lysate). After adding the amebocytes from the horseshoe crab to the serum, coagulation is not observed. What conclusion can you draw from this?

A. The patient’s serum contains endotoxin.

B. The patient’s serum contains exotoxin.

C. The patient’s serum does not contain endotoxin.

D. No conclusion can be reached because the LAL test is not used for detection of toxins.

Difficulty: Difficult

ASM Standard: 28b, 36, 38

1. In the A-B toxin, which subunit is necessary for making the initial attachment to the host cell?

A. the A subunit

B. the B subunit

C. Depending on the toxin, it could be either the A or B subunit.

D. Neither, because A-B toxins do not function this way.

Difficulty: Easy

ASM Standard: 23

1. An enterotoxin targets which type of cell?

A. cardiac cells

B. hepatic cells

C. intestinal cells

D. respiratory cells

Difficulty: Easy

ASM Standard: 23

1. Which toxin inhibits the release of glycine and GABA at the neuromuscular junction, thus preventing the relaxation of muscles?

A. anthrax

B. botulinum

C. diphtheria

D. tetanus

Difficulty: Moderate

ASM Standard: 23

1. Which is the target for the diphtheria toxin?

A. charged tRNA molecules

B. elongation factor 2

C. mRNA molecules

D. the eukaryotic ribosome

Difficulty: Difficult

ASM Standard: 23

1. Which are the attachment sites for hemagglutinin spike proteins of influenza virus?

A. CD4 receptors

B. CD8 receptors

C. heparan sulfate

D. sialic acid

Difficulty: Easy

ASM Standard: 10, 23

1. Which is the name of the toxin produced by species of Aspergillus that can cause liver cancer?

A. aflatoxin

B. citrinin

C. ochratoxin

D. patulin

Difficulty: Moderate

ASM Standard: 9, 23

1. The Panton-Valentine leukocidin from Staphylococcus aureus targets which cell type?

A. intestinal epithelial cells

B. neurons

C. red blood cells

D. white blood cells

Difficulty: Easy

ASM Standard: 13, 22, 23

1. Which surface molecules do helminths commonly express that protect them from the host immune system?

A. fibrins

B. glycans

C. hemagglutinins

D. proteases

Difficulty: Easy

ASM Standard: 9, 13, 23

True/False

1. The prodromal period is when the maximum number of pathogen particles or organisms are present in an infected host.

Difficulty: Easy

ASM Standard: 23

1. All pathogens satisfy Koch’s postulates.

Difficulty: Moderate

ASM Standard: 23

1. Facultative intracellular pathogens can reproduce both inside and outside host cells.

Difficulty: Easy

ASM Standard: 13, 22, 23

1. The severity of disease depends only on the activity of the pathogen.

Difficulty: Easy

ASM Standard: 23

1. The normal flora and microbiota of an individual can cause disease.

Difficulty: Moderate

ASM Standard: 23

1. All contacts with a pathogen will result in infection.

Difficulty: Difficult

ASM Standard: 22, 23

1. Extracellular DNA from lysed host cells can function as a means of preventing the spread of a pathogen in a host.

Difficulty: Moderate

ASM Standard: N/A

1. Endotoxin is produced only by gram-negative bacteria.

Difficulty: Easy

ASM Standard: 8

1. Giardia lamblia invades the intestinal mucosa, causing them to shrink and limiting their absorption of nutrients.

Difficulty: Moderate

ASM Standard: 9, 23

1. Bacteria, fungi, and protozoa often use similar virulence factors and mechanisms of pathogenicity.

Difficulty: Moderate

ASM Standard: 8, 9, 23

Matching

1. Match the disease nomenclature to its meaning.

Answers: A. ii., B. v., C. iv., D. i., E. iii.

Difficulty: Easy

ASM Standard: N/A

1. Match the type of infection to its proper description.

Answers: A. i., B. iv., C. v., D. ii., E. iii.

Difficulty: Easy

ASM Standard: 23

1. Match the bacterial toxin to its mechanism of action.

Answers: A. iv., B. ii., C. i., D. iii.

Difficulty: Moderate

ASM Standard: 23

1. Match the bacterial toxin to its mechanism of action.

Answers: A. iv., B. iii., C. i., D. ii.

Difficulty: Difficult

ASM Standard: 23

Fill in the Blank

1. ________ pathogens always cause disease.

Difficulty: Easy

ASM Standard: 23

1. ________ pathogens can cause disease when the host is immunocompromised.

Difficulty: Easy

ASM Standard: 23

1. ________ permit pathogens to cause disease.

Difficulty: Easy

ASM Standard: 8, 22, 23

1. ________ are molecules, receptors, or surface structures necessary for attachment to a host cell.

Difficulty: Moderate

ASM Standard: 8, 23

1. ________ are anatomic locations where pathogens can pass into host tissue.

Difficulty: Easy

ASM Standard: 23

1. A(n) ________ is a biological poison produced by certain pathogens.

Difficulty: Easy

ASM Standard: 23

1. ________ are exotoxins that can trigger a cytokine storm.

Difficulty: Easy

ASM Standard: 23

1. ________ is a yellowing of the skin and eyes due to the lysis of erythrocytes resulting from infection with either hepatitis B virus or Plasmodium falciparum.

Difficulty: Easy

ASM Standard: 23

1. ________ are extracellular structures in bacteria that are involved in conjugation and can be used as adhesins.

Difficulty: Easy

ASM Standard: 8, 23

1. A(n) ________ is when an influenza virus acquires a new hemagglutinin neuraminidase spike protein from another influenza virus coinfecting the same host cell.

Difficulty: Moderate

ASM Standard: 10, 18, 23

Short Answer

1. Explain the similarity and difference between iatrogenic and nosocomial diseases.

Sample

Difficulty: Easy

ASM Standard: 23

1. Why are not all communicable diseases contagious?

Sample

Difficulty: Moderate

ASM Standard: 23

1. Name three different types or classes of noninfectious diseases.

Sample

Difficulty: Moderate

ASM Standard: 23

1. On the axes below, sketch and identify the five periods of disease progression, and show the severity of symptoms at each stage.

Sample

Difficulty: Moderate

ASM Standard: 23

1. (a) Which part of the body does Helicobacter pylori colonize?

(b) What is the virulence factor produced by H. pylori that allows it to survive in that location?

Sample

Difficulty: Moderate

ASM Standard: 13, 22, 23

1. Explain the similarity and difference between chronic and latent infections.

Sample

Difficulty: Moderate

ASM Standard: 23

1. What is the parenteral route?

Sample

Difficulty: Moderate

ASM Standard: 23

1. (a) Explain what a capsule is and how it functions as a virulence factor.

(b) Besides bacteria, do any pathogenic eukaryotic microorganisms produce a capsule?

Sample

Difficulty: Difficult

ASM Standard: 8, 9, 13, 23

1. What are the four steps of pathogenesis?

Sample

Difficulty: Easy

ASM Standard: 23

1. Describe two ways bacterial pathogens can initiate endocytosis into a nonphagocytic host cell.

Sample

Difficulty: Moderate

ASM Standard: 8, 22, 23

1. How do hyaluronidase and collagenase promote invasion?

Sample

Difficulty: Easy

ASM Standard: 22, 23

1. In A-B toxins, how does the A subunit separate from the B subunit inside the host cell?

Sample

Difficulty: Moderate

ASM Standard: 23

1. Explain the similarities and differences between the mechanisms of the botulinum and tetanus toxins.

Sample

Difficulty: Moderate

ASM Standard: 23

1. Why must the flu vaccine (flu shot) be given every year?

Sample

Difficulty: Moderate

ASM Standard: 10, 23

1. What are four ways that helminths protect themselves from the host immune system?

Sample

Difficulty: Moderate

ASM Standard: 9, 23

Brief Essay

Essay Question Rubric

Assume rating/grading scale for the question ranges from 0 to 3 points.

Questions 70 and 71 involve the following scenario:

You are working in a hospital and have discovered what you believe to be a new bacterial pathogen that infects both humans and mice. The pathogen causes a nosocomial disease of conjunctivitis. You now wish to characterize this pathogen.

1. You take a conjunctival swab of an infected patient and culture it for any bacteria. You isolate a bacterial pathogen and grow it in pure culture. Using microscopy and a negative stain, you observe the following:

(credit: American Society for Microbiology)

(a) What shape do these cells have?

(b) What is the structure surrounding these cells?

(c) How could you use Koch’s postulates to determine if this bacterium is the causative agent of the conjunctivitis?

(d) How could you use molecular Koch’s postulates to see if the structure surrounding each cell is necessary for the pathogen’s virulence?

Difficulty: Moderate

ASM Standard: 6, 8, 23, 32, 36, 38

1. You take various amounts of the pathogen and infect a group of mice. After a week, you record the number of mice that are alive and dead. The data are shown below.

(a) Prepare a graph of percent mortality versus concentration of pathogen.

(b) Using the graph, calculate the LD₅₀.

(c) You wish to compare the LD₅₀ of this pathogen to Pseudomonas aeruginosa, another known bacterial pathogen that causes nosocomial diseases. If the LD₅₀ of P. aeruginosa for mice is 10⁴, would you say that your new pathogen is more or less virulent than P. aeruginosa? Be sure to explain your answer.

Difficulty: Difficult

ASM Standard: 23, 28b, 29, 36, 38

1. Compare and contrast endotoxins and exotoxins. Specifically address their source, composition, effect on the host, and heat stability. Also, compare their LD₅₀s.

Difficulty: Moderate

ASM Standard: 23

1. Answer the following questions regarding the cholera toxin:

(a) What organism produces this toxin? Briefly identify the shape and cell envelope of this organism.

(b) In which class of toxin is the cholera toxin?

(c) What results from ingestion of the cholera toxin? Be sure to describe in detail the mechanism of action.

Difficulty: Moderate

ASM Standard: 12, 13, 22, 23

1. Explain how Candida albicans, a fungus that is part of the normal flora/microbiota, is an opportunistic pathogen and can cause disease. What diseases can it cause?

Difficulty: Moderate

ASM Standard: 12, 13, 22, 23

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