LAB UNIT TWO TEST BANK

CH. 25 Questions

Pasteur and others observed that infecting an animal with ______protected the animal against______.

  1. Pseudomonas aeruginosa; Bacillus anthracis
  2. Bacillus anthracis; Pseudomonas aeruginosa
  3. Staphylococcus aureus; Bacillus anthracis
  4. Bacillus anthracis; Pseudomonas aeruginosa
  5. Bacillus anthracis; Bacillus anthracis

In 1928, Alexander Fleming found that culture filtrates of Penicillium inhibited the growth of many ______of staphylococci.

  1. gram-negative
  2. gram-positive

Actinomycetes remain an important source of antibiotics.

  1. True
  2. False

Chemicals absorbed or used internally to fight infection are called what?

  1. Antibiotic drugs
  2. Synthetic drugs
  3. Antimicrobial drugs
  4. Natural drugs

A pathogen is a disease-inhibiting organism.

  1. True
  2. False

What is a Petri plate containing nutrient agar with antibiotic discs, inoculated uniformly over its entire surfacecalled?

  1. Agar-diffusion method
  2. Complete-diffusion method
  3. Disk-diffusion method
  4. Petri-diffusion method

An effective antimicrobial agent will inhibit bacterial growth, and measurements can be made of the size of the zones of inhibition around the disks.

  1. True
  2. False

The size of inhibition is affected by what factors?

  1. diffusion rate of the antimicrobial agent
  2. growth rate of organism
  3. diffusion rate of bacteria
  4. All of the above
  5. A and B

What standardized test for agar diffusion is performed in clinical laboratories with strict quality controls?

  1. Fleming-Kirby test
  2. James-Kirby test
  3. Kirby-David test
  4. Kirby- Bauer test

The minimum inhibitory concentration (MIC) of an antibiotic is determined by testing for bacterial growth in dilutions of the ______in ______.

  1. pathogen in nutrient agar
  2. pathogen in blood agar
  3. antibiotic in blood agar
  4. antibiotic in nutrient agar

Who observed antibiosis around a Penicillium mold growth on a culture of staphylococci?

  1. Louis Pasteur
  2. Alexander Fleming
  3. Paul Ehrlich
  4. Robert Hook

In 1940, ______isolated the antibiotic streptomycin, produced by Actinomycetes.

  1. Alexander Fleming
  2. Louis Pasteur
  3. Selman A.Waksman
  4. Paul Ehrlich

Kirby-Bauer test uses Mueller-Hinton agar. T

Mueller-Hinton agar allows the antimicrobial agent to diffuse freely. T

The observation that some microbes inhibited the growth of others was made as early as

  1. 1800
  2. 1940
  3. 1874
  4. 1600

Chapter 45

What is secreted by the skin’s oil glands that inhibit bacterial growth?

A. water

B. sebum

C. salt

D. sugar

What contributes to creating the skin’s hypertonic environment?

A. water

B. sebum

C. salt

D. sugar

What are the normal microbes of the skin resistant to?

a. Drying

b. High salt concentrations

c. water

d. A and B

Where are transient microbes generally most present on the body?

A. Toes

B. Hands

C. Arms

D. All of the above

E. B and C only

What does Propionibacterium produce that maintains the pH of the skin?

A. ammonium

B. propionic acid

C. water

D. weak acids and bases

What pH level does the skin generally stay between?

a. 1 and 2

b. 3 and 4

c. 3 and 5

d. 4 and 6

What is the most common type of bacteria found on the skin?

a. Gram negative

b. Gram positive

c. Salt tolerant

d. B and C

True or False.

Staphylococcus aureus is normally found on the skin and is considered an opportunistic pathogen.True

The skin is generally an inhospitable environment for most microorganisms. TRUE

Salts in perspiration create a hypotonic environment.FALSE (hypertonic)

Perspiration and sebum from the skin contribute to the environment of the normal microbiota of the skin.TRUE

Propionibacterium live in hair follicles. True

The epidermis is composed of what type of cells?

A)Keratin

B)Collagen

C)Elastic

D)A and B

Choose from the following microbes that are part of the normal microbiota of the skin.

A)Streptococcus

B)Staph. aureus

C)Propionibacterium

D)All of the above

E)A and B only

F)B and C only

Which agar is selective for salt-tolerant organisms?

A)Nutrient agar

B)EMB agar

C)Mannitol salt agar

How is mannitol salt agar differential?

A)Organisms that ferment mannitol will produce acid

B)Indicator will turn medium yellow.

C)Indicator will turn purple.

D)A and B

E)A and C

What enzyme(s) does S. aureus produce?

A)Catalase

B)Coagulase

C)Collagenase

D)Oxidase

E)All of the above

F)A and B only

G)A, B, and C only

What is the purpose of testing for the presence of coagulase?

A)Distinguish S. aureus from other species of Staphylococcus.

B)Distinguish S. aureus from proprionibacterium.

C)Distinguish Gram positive from Gram negative organisms.

D)All of the above.

What is an indicator of the presence of coagulase?

A)Clumping

B)No clumping

CHAPTER 46

Alpha-hemolysis is ______.

  1. No hemolysis, and no change in the blood agar around the colony
  2. Green, cloudy zone around the colony. Partial destruction of RBC's
  3. Complete hemolysis, giving a clear zone with a clean edge around the colony
  4. All of the above

Beta-hemolysis is complete hemolysis, giving a clear zone with a clean edge around the colony.

True False

Gamma-hemolysis is no hemolysis and no change in the blood agar around the colony.

True False

The upper respiratory tract consists of the larynx and trachea.

True False

The lower respiratory tract consists of the nose and throat.

True False

Over 90% of streptococcal infections are caused by ______.

  1. Streptococcus
  2. Neisseria
  3. Beta-hemolytic group A streptococci
  4. Haemophilus

What does the lower respiratory tract consist of?

A. bronchial tubes and alveoli

B. trachea, bronchial tubes, and alveoli

C. larynx, trachea, bronchial tubes, and alveoli

B. throat, larynx, trachea, bronchial tubes, and alveoli

C. nose, throat, larynx, trachea, bronchial tubes, and alveoli

Is the upper respiratory tract normally sterile?

A. Yes

B. No

Is the lower respiratory tract normally sterile?

A. Yes

B. No

C. Depends on how polluted the air is

Is it normal to find Staphylococcus, Streptococcus, Neisseria, and Haemophilus living in the throat?

A. Yes

B. No

What are the predominant organisms in the throat cultures?

A. Staphylococcus

B.Streptococcus

What are hemolysins produced by?

A. Staphylococcus

B.Streptococcus

C. Both A and B

CHAPTER 51

What does IMViC stand for?

I indole production from breaking down tryptophan

M methyl red test for acid production from breaking down glucose

V Voges-Proskauer test for production of acetoin from breaking down glucose in the butanediol pathway

C for the use of citrate as a sole carbon source

What method(s) have been developed that provide a large number of results from one inoculation?

A: Rapid identification methods.

Why are systems developed to identify Enterobacteriaceae?

A: To differentiateamong the species contained within the two major groups of gram-negative organisms, known as the enterics(lactose fermenters) and the non-fermenters of lactose. Both groups are common causes of bacterial infections in humans.

Why is an oxidase test performed on a culture before using either an API 20E test strip or an Enterotube to identify the culture?

A: API 20E and Enterotube II are for the identification of oxidase- negative bacteria. If the oxidase test is positive, these two methods of identification would be useless.

Which of the following is TRUE regarding the BENEFITS of using the Enterotube?

  1. You find out everything you need to know about your unknown
  2. It provides quick results for a large number of tests from one inoculation
  3. Motility results are provided and are visible with the tube

Which of the following results are NOT provided from the Enterotube?

  1. Indole
  2. Methyl red
  3. Voges-Proskauer (VP)
  4. Motility
  5. citrate

The IMViC tests were developed as a means of ______members of the Enterobacteriaceae, particularly the ______, to determine if drinking water is contaminated with sewage.

  1. Separating, coliforms
  2. Combining; coliforms
  3. Separating, pathogens
  4. Combining; pathogens

Comparisons between rapid identification methods and conventional culture methods show that they are as accurate as ______.

  1. Conventional beaker methods
  2. Conventional test-tube methods
  3. Conventional agar methods
  4. Conventional petri-dish methods

ANTIMICROBIALS

True or False.

The antibiotic with the largest zone of inhibition is the most effective one.

False

Just because one zone is the largest, does NOT mean that is the most effective antibiotic

True

What types of organisms do narrow spectrum antibiotics kill?

  1. Either Gram positive or Gram negative, but not both
  2. Always Gram negative only
  3. Always Gram positive only
  4. Both gram positive and gram negative
  5. Neither Gram positive or Gram negative

What types of organisms do broad spectrum antibiotics kill?

a. Either Gram positive or Gram negative, but not both

b. Always Gram negative only

c. Always Gram positive only

d. Both gram positive and gram negative

e. Neither Gram positive or Gram negative

Why is it always good to be careful with broad spectrum antimicrobials?

a. if there are a lot of gram negative bacteria, and you kill them, their endotoxins will be released in to the bloodstream and it could be fatal for the patient

b. if there are a lot of gram positive bacteria, and you kill them, their endotoxins will be released in to the bloodstream and it could be fatal for the patient

c. Both A and B are true

What is intermediate sensitivity of an antimicrobial drug?

  1. it implies clinical efficacy only in body sites where the drugs are physiologically concentrated
  2. it implies clinical efficacy only when higher than normal dose is used
  3. it implies clinical efficacy if given two drugs at a lower dosage
  4. it implies clinical efficacy if the patient is given drugs they are only slightly allergic to
  5. Both A and B

If a patient is allergic to the medication that needs to be prescribed for them, what is the next best option for their care?

  1. choosing two antibiotics in the intermediate sensitivity category
  2. choosing two antibiotics in the sensitive category
  3. choosing two antibiotics in the resistant category
  4. choosing one antibiotic in the intermediate category

What is the zone of inhibition?

  1. the zone on the inner part of the disc with little bacterial growth
  2. the zone that is clear around the disc, with no bacterial growth.
  3. the zone that is covered with bacterial growth

What does the zone of inhibition measure?

a. the effectiveness of the antimicrobials only when checked against the Kirby-Bauer chart

b. the effectiveness of the antimicrobials only pertaining to intermediate level antibiotics

c. the effectiveness of the antimicrobials only pertaining to sensitive level antibiotics

d. the effectiveness of the antimicrobials only pertaining to resistant level antibiotics

ENTERIC UNKNOWNS

The goal when dealing with enteric unknown is to determine the genus of the organism you have

  1. True
  2. False

Characteristics of all Enterobacteriaceae include

  1. Gram negative rods
  2. Oxidase negative
  3. Catalase positive
  4. Facultative anaerobes
  5. If they are motile, they have peritrichous flagella, so they can run and tumble.
  6. Only A, B, and C
  7. All of the above

Coliforms are found in

  1. The soil
  2. Warm blooded animals
  3. Gastrointestinal tract
  4. Both B and C

Methyl Red (MR) is a pH indicator that starts out yellow and becomes red if acid is present

  1. True
  2. False

If an organism has the ability to ferment sugars, the end products of the fermentation process are

  1. Acids
  2. Oxidase negative
  3. Catalase positive

If the MR tube turns red, the organism was able to ferment sugars

  1. False
  2. True

What is an enzyme that breaks down milk sugar (lactose) into glucose and galactose?

A. Lactase
B. Hydrolase
C. Arginine dehydrogenase
D. None of the above

Arginine, lysine & ornithine are all examples of what?

A. Enzymes
B. Proteins
C. Sugars
D. Amino Acids

When Arginine dehydrogenase breaks down argentine (an amino acid), it becomes ornithine (another amino acid), which is more basic.

  1. True
  2. False

If an organism has the enzyme ornithine decarboxylase, what is ornithine broken down into?

  1. Cadaverine
  2. Putrescine

C. Lysine

D. Ornithine dioxide

Phenol red, in the presence of ornithine, gets less red, although in the first 48 hours it may still be just orange.

A. True

  1. False

When an animal dies, the smell of “death” is usually attributed to what?

A. Putrefaction
B. There is breakdown of a lot of protein

C. If an organism has the enzyme lysine decarboxylase; it will take lysine and break off a carboxyl group to create cadaverine, which produces the cadaver smell.
D. All of the Above

Ornithine decarboxylase turns the media more _____1____, so phenol red turns ____2___.

A. 1-Basic, 2-Pink
B. 1-Acidic, 2-Red
C. 1-Basic, 2-Red
D. 1-Acidic, 2-Pink

If an organism can use citrate as its only carbon source, the medium will become ______because acid is breaking down.

  1. Acidic (blue)
  2. Acidic (green)
  3. Basic (blue)
  4. Basic (green)

What is citrate?
A. A salt of citric acid
B. A part of the Krebs’s cycle
C. Orange food coloring
D. All of the above

E. Both A and B

When a medium contains iron and it turns black after inoculation with an organism

  1. Hydrogen sulfide has formed.
  2. Thiosulfate (the substrate) is reduced.
  3. The organism must be using sulfur as its terminal electron acceptor in the electron transport chain.
  4. All of the above

Urease is an enzyme that breaks down

  1. Particular sugars
  2. Particular proteins

Urease breaks urea down into

  1. Ammonia
  2. CO2
  3. Urine
  4. All of the above
  5. Both A and B only

Which of the following are true in terms of Urea test?

  1. The indicator is phenol red.
  2. Positive is pink, negative is yellow.
  3. Urea is made when proteins are broken down.
  4. The smell of OLD urine is from ammonia.
  5. All of the above

Tryptophan deaminase (TDA) tests for the presence of ______.

  1. fat
  2. turkey
  3. pyruvic acid
  4. blood

In an Indole test, a red ring is positive.TRUE:

To test for indole, add Kovac’s reagent.TRUE:

A positive Voges-Proskauer test means the organism uses the butanediol fermentation pathway.TRUE:

Voges-Proskauer test checks for the production of

  1. acetoin
  2. acetone
  3. acid

The gel test is to determine the presence of an enzyme that breaks down gelatin

A. False

B. True

What happens if the gelatinase enzyme is present?

A. Makes the gelatin solid

B. it breaks the gelatin down and liquefies it

If a sugar tubes turn yellow, what does this indicate?

A. The tube has acid, so the sugars were used (broken down) by the bacteria

B. The tube has no acid, so the sugars were used (broken down) by the bacteria

C. The tube has acid, so the sugars were not used (broken down) by the bacteria

D. The tube has no acid, so the sugars were not used (broken down) by the bacteria

What is fermentation?

A. Aerobic respiration

B. Anaerobic respiration

TSI medium contains .

  1. Three sugars
  2. Iron (Fe ++)
  3. Thiosulfate (oxidized sulfur)
  4. Phenol red (indicator where acids is yellow and basic is red)
  5. All of the above

When protein is digested, the pH becomes .

  1. Acid
  2. Base
  3. Amino acids
  4. Glucose

When sugar is fermented, the pH becomes .

  1. Acidic
  2. Basic
  3. Amino acid
  4. Glucose

A TSI slant that is all yellow is recorded as A/A. TRUE

A TSI slant that is red at the top and yellow at the butt is recorded as K/A. TRUE

A positive MRVP broth will be what color?

  1. Red
  2. Yellow
  3. Blue
  4. Green

A negative MRVP broth will be what color?

  1. Red
  2. Yellow
  3. Blue
  4. Green

True or false. In a litmus milk test, one must shake the tubes to mix the contents.

False

When does litmus change color?

a. When oxidized

b. It doesn’t

c. When deoxidized

d. All the time

What will be the color of litmus milk if the solution is acidic?

a. Pink

b. Purple

c. Blue

d. White

What will be the color of litmus milk if the solution is basic?

a. Bluish

b. Reddish

c. Yellowish

d. white

What color is a positive nitrate test?

a. After adding the first two reagents, it turns red

b. If there is no color change after adding the first two reagents, add zinc powder and it still does not turn red

c. If there is no color change after adding the first two reagents, add zinc powder and it turns red

d. Both A and B

e. Both A and C

What is the enzyme that breaks down H2O2 into H20 and O2?

a. Coagulase

b. Oxidase

c. Catalase

d. Both A and B

e. Both B and C

True or False.

If hydrogen peroxide is added and it bubbles the test is negative for catalase. False

Methyl Red starts out yellow and becomes red when acid is present True

Phenol Red starts out red and becomes yellow when acid is present True

Phenol Red is used for media with a lower pH than Methyl RedTrue

What color would urea broth be if it produced ammonia (positive test)?

  1. Pink
  2. Clear
  3. Black

What color would urea broth be if it produced acid (negative test)?

  1. Yellow
  2. Clear
  3. Black

GRAM NEGATIVE ORGANISMS

When the color white is present in the Litmus milk test, what does it mean?

  1. Curds formed
  2. It fermented lactose and is acidic
  3. Litmus was reduced and became clear
  4. The casein protein in the milk was broken down.

When the color pink is present in the Litmus milk test, what does it mean?

  1. Curds formed
  2. It fermented lactose and is acidic
  3. Litmus was reduced and became clear
  4. the casein protein in the milk was broken down.

When the color blue is present in the Litmus milk test, what does it mean?

  1. Curds formed
  2. it fermented lactose and is acidic
  3. Litmus was reduced and became clear
  4. The pH is basic, so lactose was not fermented

What does the brown ring around the tube in the Litmus milk test mean?

  1. Gas in the curd
  2. Curds formed
  3. the pH is basic, so lactose was not fermented
  4. the casein protein in the milk was broken down(proteolysis)

Match the letter designations to their color results in the litmus milk test

White R

Pink A

Bluish K

Curds formed C

Gas formed G

Brown ring P

Motility Test: Which one is positive?

  1. Tube 1
  2. Tube 2
  3. Tube 3
  4. None of them