Deck 27: Microbial Interactions With Humans

Question 1

Attenuation occurs in a laboratory, because

A) non virulent or weakly virulent mutants grow faster in vitro in laboratory media.
B) patients are generally treated with drugs that induce attenuation.
C) pathogens lose virulence with age.
D) none of the above are true.

Answer 1

A

Question 2

Which of the following is more likely to cause urinary tract infections?

A) non- fimbriated strains of Escherichia coli
B) fimbriated strains of Escherichia coli
C) both fimbriated and non- fimbriated strains of Escherichia coli
D) none of the above

Answer 2

B

Question 3

The following compounds are all produced by intestinal microflora EXCEPT

A) vitamin K.
B) vitamin B12.
C) vitamin C.
D) flatus.

Answer 3

C

Question 4

Influenza virus targets

A) oral cavity cells.
B) lung mucosal cells.
C) gastrointestinal cells.
D) none of the above.

Question 5

Capsules are particularly important for

A) protecting bacteria from host defense mechanisms.
B) making bacteria less pathogenic.
C) making bacteria more vulnerable to host defense mechanisms.
D) all of the above.

Question 6

The decrease or loss of virulence of a pathogen is referred to as

A) attenuation.
B) lethal dose.
C) aging.
D) disinfectivity.

Question 7

Decalcification of the tooth enamel due to the production of high concentrations of organic acids in the mouth is known as

A) dental caries.
B) dental plaque.
C) microbial enamel decalcification.
D) degenerative plaque.

Question 8

The following bacteria are all implicated in dental caries EXCEPT

A) Streptococcus mutans.
B) Escherichia coli.
C) Streptococcus sobrinus.
D) all of the above.

Question 9

Which of the following are NOT found in the gastrointestinal tract of healthy humans?

A) Bacteroides
B) Clostridium
C) Protists
D) Escherichia coli

Question 10

Only particles smaller than _ µm in diameter reach the lungs.

A) 10
B) 20
C) 30
D) 40

Question 11

Pathogenic strains of Escherichia coli usually express

A) plaques.
B) colonization factor antigens (CFA).
C) slime layers.
D) capsules.

Question 12

In the absence of the full complement of normal flora, due to orally taken antibiotics, opportunistic microorganisms such as can become established.

A) Clostridium difficile
B) Staphylococcus
C) Proteus
D) all of the above

Question 13

Gingivitis is cause by all of the following organisms EXCEPT

A) Rothia.
B) Methanobrevibacter.
C) Capnocytophaga.
D) Escherichia coli.

Question 14

Which of these microorganisms is most likely to be found in the gut?

A) Roseobacter denitrificans
B) Streptococcus sobrinus
C) Helicobacter pylori
D) Streptococcus mutans

Question 15

Which of the following is NOT important for the adherence of bacteria to other bacteria as well as to host tissue?

A) gycocalyx
B) slime layer
C) adherence polymers
D) capsule

Question 16

Which of the following affect(s) pathogen growth?

A) availability of microbial nutrients
B) temperature
C) pH
D) all of the above

Question 17

Streptocoocus pyogens utilizes M protein and _ to form microfibrils that facilitate attachment to host cells.

A) mucus
B) lipoteichoic acid
C) plaque
D) none of the above

Question 18

Pathogenicity is

A) the ability of the host to resist damage by the pathogen.
B) the ability of the pathogen to inflict damage on the host.
C) the ability of the host to inflict damage on the pathogen.
D) all of the above.

Question 19

A polymer coat consisting of a dense, well- defined polymer layer surrounding a cell is called a

A) slime mold.
B) capsule.
C) lipopolysaccharide.
D) gycocalyx.

Question 20

Mucous membranes are frequently coated with a protective liquid called

A) mucus.
B) membrane fluid.
C) epithelial fluid.
D) none of the above.

Question 21

The spread of pathogens through the blood and lymph systems that results in a bloodborne systemic infection is called

A) cancer.
B) septicemia.
C) bacteremia.
D) pathogenesis.

Question 22

Siderophores from some pathogens remove iron from the host protein(s)

A) lactoferrin
B) transferrin
C) both lactoferrin and transferrin
D) none of the above

Question 23

The relative ability of a bacterium to harm its host is known as _ .

Question 24

The first microorganisms to colonize the gut of a baby born in the developed world are
and in the developing world are .

Question 25

The process by which white blood cells ingest and kill bacteria is called .

Question 26

Cytolytic toxins

A) cause cell lysis and death.
B) damage host cytoplasmic membrane.
C) are extracellular proteins.
D) are all of the above.

Question 27

Before teething, bacteria in the mouth are anaerobes and .

Question 28

The vagina of adult female is

A) weakly alkaline.
B) highly alkaline.
C) weakly acidic.
D) highly acidic.

Question 29

Which of the following bacterial cell surface protein structures function in the attachment process?

A) fimbriae
B) pili
C) both fimbriae and pili
D) none of the above

Question 30

Extensive growth of the streptococci in a thick bacterial layer on acidic glycoproteins on the teeth is called .

Question 31

Virulence is the relative ability of a to cause disease.

Question 32

The collective term for the organisms living on or in the human body is .

Question 33

Neisseria gonorrhoeae adheres to mucosal epithelial cells in the

A) genitourinary tract.
B) eye.
C) rectum.
D) all of the above.

Question 34

To control tooth decay in developed countries, salts are commonly added to municipal drinking water and toothpastes.

A) lead
B) fluoride
C) iron
D) sodium

Question 35

Which genus does NOT produce hyaluronidase?

A) Procholorococcus
B) Clostridia
C) Streptococcus
D) Staphylococcus

Question 36

Which disease CANNOT be prevented via the use of a vaccine generated from an attenuated pathogen?

A) tuberculosis
B) mumps
C) measles
D) malaria

Question 37

The dose of an antigen that kills 50% of animals in a test group and is used to estimate the virulence of a pathogen is known as .

Question 38

Normal flora in the duodenum are

A) tolerant to acidic environments.
B) similar to the microflora in the stomach.
C) tolerant to alkaline environments.
D) both A and B.

Question 39

in saliva cleaves glycosidic linkages in peptidoglycan present in bacterial cell walls, weakening the wall, and causing cell lysis.

Question 40

The ability of an organism to cause disease by means of a preformed toxin that inhibits host cell function or kills host cells is called .

Question 41

Endotoxins are released in large amounts only when cells lyse.

Question 42

To speed the establishment of competitive flora, recolonization of the gut by desired species can be accomplished by the administration of .

Question 43

Toxic proteins released from pathogen cells as they grow are called .

Question 44

Hormones that are produced under stress boost normal immune responses and play a role in stress- mediated disease resistance.

Question 45

The environment in which an individual is born determines the kinds of microorganisms that would colonize his or her body.

Question 46

The number of Vibrio cholera cells necessary to produce cholera in an exposed individual is drastically reduced if the individual is malnourished.

Question 47

A loose network of polymers extending outward from a cell is called a(n) .

Question 48

The macromolecules responsible for bacterial adherence that are not covalently attached to bacteria are collectively called _ _.

Question 49

All microorganisms that live in the human body are harmful.

Question 50

microorganisms colonize, invade, and damage the human body through indirect means.

Question 51

The upper respiratory tract usually has a considerable amount of resident microflora in a healthy adult.

Question 52

Environmental and host factors that influence the composition of resident microflora on the skin include the , and .

Question 53

A _ is a damage or injury to a host organism that impairs its function.

Question 54

Streptococcus mutans can produce dextran when sucrose is present in the absence of the enzyme dextransucrase.

Question 55

Clostridium botulinum cannot produce toxins in improperly preserved foods.

Question 56

The process by which microorganisms cause diseases is known as .

Question 57

Bacteria make up about one- third the weight of fecal matter.

Question 58

are microbial infections acquired by hospital patients with noninfectious diseases because they are compromised hosts.

Question 59

The condition that results when some organisms are shed in the bloodstream and distributed to distant parts of the body during bacterial growth in tissues is called
.

Question 60

Animals that lack CXCR4 and CCR5 proteins are immune to HIV infection.

Question 61

Diphtheria toxin inactivates elongation factor 2 by catalyzing the attachment of adenosine diphosphate ribose from NAD+.

Question 62

The acidic pH (about pH 2) of the mouth makes it a virtually sterile environment.

Question 63

Diets high in sucrose promote dental caries.

Question 64

Gram- positive bacteria produce endotoxins.

Question 65

Malassezia spp. are the most common fungi present on the skin of humans.

Question 66

In AIDS patients, the body's normal microflora causes diseases because the host's resistance is compromised.

Question 67

The toxic lipopolysaccharides produced by most gram- negative bacteria are called exotoxins.

Question 68

Brucella abortus grows very rapidly in the placenta of cattle, because the placenta is the only tissue with the right nutrient needed for its growth.

Question 69

When does an infection become a disease?

Question 70

Why are some microorganisms specialized to only certain parts of the body?

Question 71

Diseases of warm- blooded animals are rarely transferred to cold- blooded animals.

Question 72

How do anaerobic microflora survive in the mouth although humans have a high intake of oxygen through the mouth.

Question 73

Normal microflora are usually found in the blood, lymph, and nervous systems of the body.

Question 74

Invasion is the ability of a pathogen to enter into host cells or tissues, spread, and cause disease.

Question 75

The Limulus amebocyte lysate assay is used to detect endotoxin in clinical samples such as serum or cerebrospinal fluid.

Question 76

Why does the influenza virus that occurs in nature as an avian pathogen infect humans?

Question 77

Vaginal acidity in the adult female is due to acid production by Lactobacillus acidophilus.

Question 78

An opportunistic pathogen causes disease only in the presence of normal host resistance.

Question 79

Explain how Clostridium tetani cells that rarely leave their initial site of infection can cause death in their hosts.

Question 80

There is a high occurrence of dental caries and high amounts of S. mutans present in the plaque of Tanzanian children.