A substance that can inactivate all living organisms except spores is called a(n)... Question 24 options:
Sterilant
Disinfectant
Antiseptic
Surfactant
Question 25

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Both the Kirby-Bauer disk test and the E-test are used to measure the sensitivity of bacteria to different agents. All the statements below are true EXCEPT
Question 25 options:
In both test a clear zone of inhibition is observed when the bacterium is sensitive to the agent tested.
In the disk test the zone is tear-shaped while in the E-test is circular.
For the disk-test, the size of the zone of inhibition is compared to that of a standard.
The E-test can be read directly, providing a minimum inhibitory concentration.
Larger zones of inhibition reflect higher sensitivity.
Question 26

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Autoclaving is the most effective method of moist heat sterilization.
Question 26 options:
True
False
Question 27

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Which of the following is a limitation of the autoclave?
Question 27 options:
It cannot be used with heat-labile materials.
It requires an excessively long time to achieve sterilization.
It cannot kill endospores.
It cannot be used with glassware.
It cannot inactivate viruses.
Question 28

Which of the following chemical agents is used for sterilization?
Question 28 options:
ethylene oxide
alcohol
chlorine
phenolics
soap
Question 29
Ethylene oxide
Question 29 options:
requires high heat to be effective.
is a good antiseptic.
is not sporicidal.
is a sterilizing agent.
is the active chemical in household bleach.
Question 30

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An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)
Question 30 options:
disinfectant.
virucide.
fungicide.
aseptic.
antiseptic.
Question 31
Antibiotics are natural antibacterials
Question 31 options:
True
False
Question 32

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You streak an unknown bacterium on a blood agar plate. After incubation you notice a distinct zone around the colonies that is clear. What does that mean?
Question 32 options:
The bacteria excrete acid
The bacteria excrete an enzyme that degrades protein
The bacteria are alpha-hemolytic
The bacteria are beta-hemolytic
The bacteria are gamma-hemolytic.
Question 33

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Name three factors that inhibit bacterial growth on the skin.
Question 33 options:
Sebum
Salt
Dryness
Catalase
Coagulase
Question 34

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S. pneumoniae is distinguished from other Strep by
Question 34 options:
Catalase
Coagulase
Bile solubility
Alpha hemolysis
Colony color
Question 35

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Streptococci are gram and catalase
Question 35 options:
Positive; negative
Negative; positive
Negative; negative
Positive; positive
Question 36
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A sample of urine (less than 1 ml) from a patient is spread on a MacConkey agar plate. There are 101 red colonies on the plate. This indicates the patient has a urinary tract infection.
Question 36 options:
True
False
Question 37

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Most bacteria on the skin can survive there because they are able to grow in the presence of
Question 37 options:
Sebum
Salt
Light
Soap
antiseptic
Question 38
Bacitracin was added to the Mitis Salivarius medium to
Question 38 options:
kill Strep mutans
kill all bacteria except those that are Strep
kill all Strep species except Strep mutans
kill bacteria that aren't oral bacteria
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What is (are) the criterion(criteria) for a urinary tract infection (UTI)?
Question 39 options:
A) Presence of any bacteria in the urine.

B) More than 105 CFU/ml in urine.

C) 100 coliforms or more per ml urine

D) B & C

E) A, B, & C

Question 40

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The antibiotic that distinguishes Strep. pyogenes from Strep. pneumoniae is
Question 40 options:
Bacitracin
Optochin
Streptomycin
Erythromycin
Question 41

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The Enterotube is useful to distinguish between Gram positives and Gram negative bacteria.
Question 41 options:
True
False