Unknown Bacterial Identification quiz - Micro. Crider
This image shows an unknown bacterium after 24-hour incubation on a blood agar plate. What hemolytic result is seen here?
Alpha hemolysis
An unknown bacterium was streaked on the top half of a blood agar plate and a bacitracin disc was placed on it. A vertical streak with the unknown bacterium was made, along with an intersecting horizontal streak with S. aureus. After 24 hours, your plate looked like this image. What can you determine from this result?
Bacitracin resistant / CAMP negative
An unknown bacterium was streaked on the top half of a blood agar plate and a bacitracin disc was placed on it. A vertical streak with the unknown bacterium was made, along with an intersecting horizontal streak with S. aureus. After 24 hours, your plate looked like this image. What can you determine from this result?
Bacitracin resistant / CAMP positive
The most reliable source of information regarding the tests that can be used to identify a particular bacterial isolate and the expected results is ____________________ Manual.
Bergey's
What is the internationally recognized reference for bacterial classification and identification?
Bergey's Manual
This image shows an unknown bacterium after 24 hours incubation on a blood agar plate. What hemolytic result is seen here?
Beta hemolysis
What type of medium is enriched with a complex organic substance, allowing for growth of fastidious organisms from the human body?
Blood agar
What biochemical test is most useful in differentiating Staphylococcus species from Streptococcus species?
Catalase test
Which of the following is an example of a morphological characteristic that could be used in the bacterial identification process?
Cell shape
Which of the following biochemical tests requires growth of the microorganism on an agar slant prepared from a specific medium? -Oxidase test -gram stain -Methyl red test -Citrate test -SIM
Citrate test
What cultural characteristics can be described by color and shape?
Colony morphology
Which would be the main reason for trying to identify which antibiotics would be the best to treat a particular patient?
Diagnosis and treatment of infections
Which of the following types of media might be particularly helpful in the isolation of a bacterial species from a mixed bacterial culture? -Nutrient -Differential -Selective -Enriched
Differential Selective
(T/F) Bergey's Manual is an excellent resource for the identification of fungi and viruses as well as bacteria
False
(T/F) The most important approach to identifying unknowns is the phenotypic method.
False
This image shows an unknown bacterium after 24 hour incubation on a blood agar plate. What hemolytic result is seen here?
Gamma hemolysis
Which methods used in bacterial identification usually work best in organisms that cannot be cultured?
Genotypic methods
__________________ identification methods examine the DNA sequence of an organism, whereas __________________ identification methods use antibody-antigen reactions to identify microorganisms.
Genotypic; immunologic
This is how the KIA test looks after 24 hours of incubation. Is the unknown bacterium positive or negative for glucose fermentation, lactose fermentation, and H2S production?
Glucose fermentation = Positive Lactose fermentation = Negative H2S = Positive
This is how the KIA test looks after 24 hours of incubation. Is the unknown bacterium positive or negative for glucose fermentation, lactose fermentation, and H2S production?
Glucose fermentation = Positive Lactose fermentation = Positive H2S =Negative
This is how the KIA test looks after 24 hours of incubation. Is the unknown bacterium positive or negative for glucose fermentation, lactose fermentation, and H2S production?
Glucose fermentation = positive Lactose fermentation = Positive H2S = Positive
This is how the KIA test looks after 24 hours of incubation. Is the unknown bacterium positive or negative for glucose fermentation, lactose fermentation, and H2S production?
Glucose fermentation = positive lactose fermentation = negative H2S = negative
This is how the SIM medium looks after 24 hours and the addition of indole reagent. Is the unknown bacterium positive or negative for H2S production, indole production, and motility?
H2S = Negative Indole = Positive Motility = Positive
This is how the SIM medium looks after 24 hours and the addition of indole reagent. Is the unknown bacterium positive or negative for H2S production, indole production, and motility?
H2S = Positive Indole = Negative Motility = Positive
Which of the following is an example of biochemical testing?
Hemolysis patterns on blood agar
Which of the following would be most valuable to confirm the identification of microorganisms isolated during a food poisoning outbreak?
Identification of microorganisms using microscopic, cultural, and physiological characteristics.
The ninth edition of Bergey's Manual of Determinative Bacteriology was designed solely for
Identifying bacteria that have already been cultured and phenotypically examined.
Which methods used to identify a microorganism causing an infection rely on the response of the host, rather than observation of the microorganism's properties?
Immunologic methods
Which of the following media tests can provide information on more than one biochemical characteristic? -Kilgler's iron-agar (KIA) -gram staining -oxidase test -SIM tubes
Kilgler's iron-agar (KIA) SIM tubes
Which of the following is an agar plate that can indicate whether an organism ferments lactose?
MacConkey medium
After adding reagents A and B (from a nitrate kit), you see this result in image 1-a yellow color. After adding zinc, the color changes from yellow to red seen in image 2. Is the unknown bacterium positive or negative for nitrate reductase?
Negative
Is this bacterial isolate positive or negative for catalase acitvity?
Negative
Is this bacterial strain positive or negative for mannitol fermentation?
Negative
This is how the Durham tube looks after 24h. Is this bacterium positive or negative for glucose fermentation?
Negative
Twelve hours after adding a sample of bacteria to rabbit serum, your tube looks like this. Are the unknown bacteria positive or negative for coagulase activity?
Negative
You conducted a methyl red test. Is the result positive or negative?
Negative
You conducted an oxidase test to detect the production of an oxidase enzyme. Is the result positive or negative?
Negative
You evaluate a bile esculin agar slant 24 hours after you inoculated it with your unknown bacterium. Is this bacterium positive or negative for esculin hydrolysis?
Negative
Which biochemical test would be most useful for differentiating Streptococcus pneumonia and viridans streptococci?
Optochin susceptibility
According to this flowchart, what test is most useful for distinguishing between Escherichia coli and Vibrio cholerae?
Oxidase test
Which method used in bacterial identification usually require culturing of the unknown bacteria?
Phenotypic
An organism has been shown to produce hydrogen sulfide and indole in its metabolism. These are examples of _________________ characteristics that can be helpful in identifying the microorganism.
Physiological
After adding reagents A and B (from a nitrate test kit), you see this result. Is the unknown bacterium positive or negative for nitrate reductase?
Positive
This is how the Durham tube looks after 24 h. Is this bacterium positive or negative for glucose fermentation?
Positive
This is how the MacConkey agar plate looks after 24 hours of incubation. Are these bacteria positive or negative for lactose fermentation?
Positive
Twelve hours after adding a sample of bacteria to rabbit plasma, your tube looks like this. Are the unknown bacteria positive or negative for coagulase activity?
Positive
You conducted a citrate test. Is this result positive or negative?
Positive
You conducted a urease test. Is this result positive or negative for urease activity?
Positive
is this bacterial strain positive or negative for mannitol fermentation?
Positive
you evaluate a bile esculin agar slant 24 hours after you inoculated it with your unknown bacterium. is the bacterium positive or negative for esculin hydrolysis?
Positive
Which of the following is a characteristic of members of the resident microbiota?
Resident microbiota can compete with and limit the growth of harmful bacteria.
You streak your unknown bacterium onto a blood agar plate and place a novobiocin disc onto the surface of the plate. After 24 hours your plate looks like this with a zone of 18 mm. Is the unknown bacterium sensitive or resistant to novobiocin?
Sensitive
You streak your unknown bacterium onto a blood agar plate and place an optochin disc on the surface of the plate. After 24 hours your plate looks like this. Is the unknown bacterium sensitive or resistant to optochin?
Sensitive
What causes the color change in a positive urease test?
The production of ammonia from urea
Which would be the main reason for identifying which organism is causing infections from contaminated peanut butter?
Tracking of infectious diseases in populations
(T/F) Multiple bacterial species can have similar staining reactions and microscopic morphology.
True
How do you determine the strain of an unknown bacterium?
You use multiple biochemical tests and pre-existing knowledge to classify the bacteria.
How do you determine the species of an unknown bacterium?
You use standard tests and pre-existing knowledge to classify the bacterium
The complete clearing or hemolysis that a bacterial isolate may produce on blood agar is called _______________ hemolysis, while partial hemolysis which produces a greenish discoloration is referred to as __________________ hemolysis.
beta; alpha
Bile esculin medium is made selective by the incorporation of _____________, and differential by the incorporation of _______________ and ferric citrate.
bile; salts
A specific example of a medium that can be used to isolate organisms from the human body because it is enriched with compounds that support the growth of fastidious organisms is _________________________ agar.
blood
What do common biochemical tests look for? -cell shape -temperature preferences -colony shape -breakdown of nutrients -specific enzyme reactions -fermentation products
breakdown of nutrients, specific enzyme reactions, fermentation products
Bergey's Manual of Determinative Bacteriology first categorizes bacteria based upon which of the following characteristics? -presence of certain enzymes -fermentation abilities -cell shape -gram stain reaction
cell shape gram stain reaction
A particular microorganism can be distinguished from several closely related microorganisms by the determination of its preferred growth temperature. This is an example of a _____________________ characteristic that can be used for identification.
cultural
the impact of microbes on public health
epidemiology
What do common biochemical tests look for? -Fermentation products -Breakdown of nutrients -Temperature preferences -Cell shape -Colony shape -Specific enzymatic reactions
fermentation products breakdown of nutrients specific enzymatic reactions
The first choice in this dichotomous key is based on the organism's
gram reaction
Which of the following microbial characteristics can be determined by growing the bacteria on blood agar? -presence of catalase -presence of coagulase enzyme -motility -hemolysis -mannitol fermentation
hemolysis
human defenses used to fight off microbial agents
immunology
Identification of bacterium cannot be made on microscopic morphology alone because
many microorganisms have similar microscopic morphology
The field of study in which medicine and microbiology intersect is known as ______________.
medical microbiology
The microorganisms that live in and on our body, generally without causing harm, are known as normal ____________________.
microbiota
The Gram stain is an example of a test that can be used to determine the _______________ characteristics of a bacterium.
morphological
the specific pathological effects of microbes on the human body
pathology
If an organism produces stable acids as an end-product of glucose fermentation, the methyl red test will be -positive -negative
positve
Before attempting to identify an unknown bacterial species, the organism must be isolated in a ____________________ culture.
pure
Which of the following are advantages of using multitest media or systems? -improved accuracy -reduction in media usage -improved efficiency -reduction in time required for identification
reduction in media usage, improved efficiency, reduction in time required for identification
When a large zone of no growth is found around an antibiotic disc being used for identification purposes, this means that the microbe is __________________ to the antibiotic.
sensitive
Which of the following body sites normally have large numbers of resident microbiota? -blood -throat -large intestine -liver -vagina -skin -brain -nose
throat, large intestine, vagina, skin, nose
