Deck 5: Requirements for Infection

Question 1

Which of the following made by bacteria destroys red blood cells in the host?

A)Coagulase
B)Hyaluronidase
C)Leukocidin
D)Collagenase
E)Hemolysin

Answer 1

Hemolysin

Question 2

To increase phagocytosis of encapsulated bacteria,the host produces

A)Antibiotics
B)Antibodies
C)Pseudopodia
D)Defensins
E)Adhesins

Answer 2

Antibodies

Question 3

Which is a portal of entry?

A)Mucous membrane
B)Skin surface
C)Gums
D)Skin cut
E)All of the choices

Answer 3

All of the choices

Question 4

What are produced by many pathogens to anchor them to host tissue?

A)Adhesions
B)Pellicles
C)Leucocidins
D)Hyaluronidase
E)Invasins

Question 5

Which of the following common pathogens is mismatched with the disease it causes?

A)Bordetella pertussis; whooping cough
B)Clostridium perfringens; tetanus
C)Vibrio cholera; cholera
D)Plasmodium falciparum; malaria
E)Treponema pallidum; syphilis

Question 6

The fecal-oral route of contamination refers to the situation where infectious pathogens exit from the host through the _____ and enter another host through the _____.

A)anus; skin
B)Respiratory tract; gastrointestinal tract
C)Anus; mouth
D)Genitourinary tract; gastrointestinal tract
E)Gastrointestinal tract; genitourinary tract

Question 7

Both M protein and mycolic acid are

A)The same thing with different names
B)Made by Mycobacterium tuberculosis
C)Produced by the host as defensive molecules
D)Part of the cell wall
E)Inducers of phagocytosis

Question 8

Which of the following diseases is not likely to have been acquired through a mucous membrane-associated portal of entry?

A)Tuberculosis
B)Tetanus
C)Gonorrhea
D)Chickenpox
E)Cholera

Question 9

A(n)_____ is a thick film of protein secreted by mucous membranes in the mouth that coats teeth and provides a substrate for Staphylococcus mutans to adhere and begin the formation of a slime layer.

A)Biofilm
B)Pellicle
C)Extracellular matrix
D)Adhesion

Question 10

Which of the following pathogens are virulent only if encapsulated?

A)Klebsiella pneumoniae
B)Bacillus anthracis
C)Yersinia pestis
D)Streptococcus pneumoniae
E)All of the choices

Question 11

Which of the following is the process by which phagocytic cells adhere to and ingest antibody-coated or complement-coated bacteria?

A)Resolution
B)Pinocytosis
C)Phagocytosis
D)Binary fission
E)Opsonization

Question 12

Connective tissue in the host is compromised by the production of _____ by bacteria.

A)Hyaluronidase
B)Capsules
C)Streptokinase
D)M protein
E)Leukocidins

Question 13

An infection in an abrasion affecting only the epidermis of the skin is unlikely to spread systemically to other sites because

A)The micro environment of the epidermis is unfavorable for microbial growth
B)The dermis beneath secretes antimicrobial substances that contain the infection
C)There is availability of blood in this layer of the skin
D)There is no availability of blood in this layer of the skin

Question 14

The respiratory tract is the main portal of entry for which of the following infectious agents?

A) C. perfringens
B) HIV
C) Influenza virus
D) S. typhi
E) V. cholera

Question 15

Which of the following is not a location where mucous membranes are found?

A)Lungs
B)Esophagus
C)Urinary bladder
D)Vagina
E)Pancreas

Question 16

A dose of 1000 bacteria can kill 50% of the animals and a dose of 2400 can kill 70% of the animals.What is the approximate LD₅₀?

A)1000
B)2400
C)150
D)1700

Question 17

What is the general term for components of a pathogen that help it to be infectious?

A)Portals of entry
B)Parenteral characteristic
C)Transmissible factors
D)Virulence factors
E)Adhesion factors

Question 18

Which of the following is not associated with the parenteral route?

A)Contaminated needles used by drug users
B)Transmission of malaria by mosquitoes
C)Contaminated food
D)Tick-derived Lyme disease
E)Blood products used by hemophiliacs

Question 19

Which of the following is incorrect regarding M proteins of Streptococcus pyogenes?

A)Induce dynamic changes in vascular permeability in the host
B)Cause a rapid loss of fluids from the body
C)Cause difficulty in ventilating the lungs
D)Produce granulomas
E)All the choices are incorrect

Question 20

Urinary tract infections are more prevalent in women than in men because

A)Women use tampons
B)Women prefer bathing to showering
C)Of the closer proximity of the anus to the urethra
D)The resident bacteria of women are different from those of men

Question 21

Disseminated intravascular clotting (DIC)is caused by

A)High levels of exotoxins
B)Low levels of exotoxins
C)High levels of endotoxins
D)Low levels of endotoxins
E)Gram-positive organisms

Question 22

The portion of the lipopolysaccharide that is toxic to the host is the

A) β subunit
B)The snare protein
C)Lipid A
D)α subunit

Question 23

Which of the following toxins inhibits the release of acetylcholine from neuromuscular junctions?

A)Botulinum toxin
B)Diphtheria toxin
C)Anthrax toxin
D)Tetanus toxin
E)Endotoxin

Question 24

The anthrax toxin is made up of

A)Cell binding protective antigen
B)Edema and lethal factors
C)Lethal factor
D)Hyaluronidase
E)Edema factor, lethal factor, and protective antigen

Question 25

"Lockjaw" is a symptom of infection with

A)Clostridium perfringens
B)Clostridium botulinum
C)Bacillus anthracis
D)Clostridium tetani
E)Yersinia pestis

Question 26

_____ enhances fibrin blood clots,whereas _____ breaks them down.

A)hemolysin; leukocidin
B)hyaluronidase; collagenase
C)coagulase; streptokinase
D)coagulase; collagenase
E)endotoxin; exotoxin

Question 27

The reason for converting toxins to toxoids for vaccine use is

A)To reduce their antigenicity
B)To increase their toxicity
C)To stimulate better immune responses
D)To retain their antigenicity but destroy their toxicity

Question 28

Explain how the bacterium Helicobacter pylori can survive the acidic environment of the stomach.What is the consequence of a Helicobacter infection?

Question 29

An autopsy report of a recently deceased person reveals Negri bodies in infected tissues.The person was probably infected by

A)Respiratory syncytial virus
B)Mycobacterium tuberculosis
C)Bacillus anthracis
D)Rabies virus
E)Yersinia pestis

Question 30

How does tooth brushing protect teeth from cavity formation?

Question 31

Many A-B toxins consist of two subunits,α and β .Which has specificity for a target cell receptor?

A)α
B)The binding site is dependent on both subunits.
C)β
D)Neither α nor β bind specifically to the target cell; the exotoxin is taken up by pinocytosis.

Question 32

Which of the following exotoxins produces an effect that is the opposite of tetanus toxin?

A)Botulinum toxin
B)Diphtheria toxin
C)Anthrax toxin
D)Tetanus toxin
E)Endotoxin toxin

Question 33

Virulence factors fall into two main classes; defensive (protecting the pathogen from destruction by the host)and offensive (destructive to host cells or triggering dangerous host responses.)Give three examples of each type and explain how each is defensive or offensive.Can you think of a virulence factor that is both defensive and offensive?

Question 34

Which of the following is not a characteristic of exotoxins?

A)Highly antigenic
B)Cause disseminated intravascular clotting (DIC)
C)Converted to toxoids for vaccine use
D)Lethal in small quantities
E)Unstable at high temperatures

Question 35

"Rice-water stool" is related to _____,which results in the release of large quantities of _____.

A)Staphylococcal diarrhea; hemolysin
B)Bacillary dysentery; protein synthesis inhibitors
C)Cholera; electrolytes
D)Salmonella food poisoning; lipopolysaccharide
E)Tetanus; snare protein proteases

Question 36

Which of the following statements is true?

A)Botulinum toxin kill neurons
B)Exotoxins are often synthesized in an inactive form
C)Exotoxins make up part of the cell wall of Gram-positive bacteria
D)Exotoxins are encoded on plasmids can be transmitted to other bacteria
E)Only one molecule of diphtheria toxin is needed to kill a host cell

Question 37

Identify three types of exotoxin and indicate their effect in the host.Provide two specific examples of each type of exotoxin and the name of the organisms that produce it.

Question 38

Which of the following is the most virulent?

A)Bordetella pertussis (whooping cough)
B)Yersinia pestis (plague)
C)Pseudomonas aeruginosa (infections of burns)
D)Clostridium difficile (antibiotic-induced colitis)
E)Candida albicans (vaginitis, thrush)

Question 39

A case of cholera appears in a village that has poor sanitation and is socio-economically depressed.The physician recommends electrolyte infusion,antibiotic treatment of those affected,and widespread sanitation of faucets,handles,and cooking utensils because

A)The endotoxin accumulates on these surfaces from contaminated water supplies
B)Vibrio cholera is transmitted via the fecal-oral route
C)The toxoids produced by Vibrio cholera are stable for long periods on the hands of people with the infection
D)If the village is not decontaminated, there will be a very high death rate due to toxic shock

Question 40

Which of the following is not a characteristic of endotoxins?

A)Stable for hours at 60°C
B)Induce fever in the host
C)Poor antigenicity
D)Located in the cell wall of Gram-negative bacteria
E)Lethal in small quantities

Question 41

How does Bacillus anthracis ensure that the activity of the anthrax toxin is exerted only inside the host cell?

Question 42

Botulinum toxin is used as a partial or cosmetic treatment for strabismus (crosseye or walleye).What is the mechanism of its action?

Question 43

What is the test used to detect the presence of endotoxins on clinical instrumentation? Explain how the test is performed.