Deck 7: Traditional Cultivation and Identification

Question 1

What name is given to the type of hemolysis that produces complete hemolysis and a clearing of the medium?

A)b
B)g
C)a
D)k

Answer 1

A
The type of hemolysis described is b.Complete lysis of erythrocytes causes clearing of the agar.

Question 2

Which medium can be described as containing crystal violet dye to inhibit the growth of gram-positive bacteria and fungi and allows many types of gram-negative bacilli to grow?

A)Thayer-Martin agar
B)MacConkey agar
C)PEA
D)Hektoen enteric agar

Answer 2

B
MacConkey agar contains crystal violet dye to inhibit the growth of gram-positive bacteria and fungi and allows many types of gram-negative bacilli to grow.

Question 3

A bacterial colony can be described as:

A)sufficiently large numbers of a bacterium that can be observable with the unaided eye.
B)derived from many different types of bacterial cells.
C)belonging to different genera and species.
D)having different genetic and phenotypic characteristics.

Answer 3

A
The multiplication of a single bacterial cell into a heap of cells large enough to be observed with the naked eye results in a colony.

Question 4

Which group of bacteria uses oxygen as a terminal electron acceptor and grows well in ambient air?

A)Aerobes
B)Anaerobes
C)Capnophiles
D)Microaerophiles

Question 5

Which medium can be described as containing hemoglobin,hemin (X factor),and the co-enzyme nicotinamide adenine dinucleotide (NAD)(V factor)?

A)Chocolate
B)CNA blood
C)BHI
D)Thioglycollate broth

Question 6

To read the hemolytic reaction accurately on a blood agar plate,the technologist must:

A)hold the plate up to the light,and observe the plate with the light coming from behind.
B)hold the plate under the light,and observe the plate with the light coming from the top.
C)hold the plate over a white background.
D)examine the plate using reflected and transmitted light.

Question 7

Which medium can be described as suppressing the growth of most gram-negative organisms while allowing gram-positive bacteria to grow?

A)Chocolate
B)CNA blood
C)BHI
D)Thioglycollate broth

Question 8

In which category of media would MacConkey agar best fit?

A)Selective
B)Differential
C)Selective and differential
D)Supportive only

Question 9

Which category of media can be described as containing specific nutrients required for the growth of particular bacterial pathogens in a patient specimen?

A)Enrichment
B)Supportive
C)Selective
D)Differential

Question 10

Which category of media can be described as containing one or more agents that are inhibitory to all organisms except those being sought?

A)Enrichment
B)Supportive
C)Selective
D)Differential

Question 11

Increased concentrations of carbon dioxide (CO₂)(5% to 10%)and approximately 15% oxygen (O₂)produce an environmental condition that best suits which type of organism?

A)Aerobes
B)Anaerobes
C)Capnophiles
D)Microaerophiles

Question 12

In which category of media would blood agar best fit?

A)Selective
B)Differential
C)Selective and differential
D)Supportive only

Question 13

The role of the agar ingredient in culture medium is to:

A)provide a nutritional base for bacterial metabolism.
B)solidify the medium and provide a stable culture surface.
C)sterilize the medium and prevent contamination.
D)support the growth of only pathogenic organisms.

Question 14

Which medium can be described as containing bile salts and dyes (e.g. ,bromothymol blue and acid fuchsin)to slow selectively the growth of most nonpathogenic gram-negative bacilli found in the gastrointestinal tract and allow Salmonella spp.and Shigella spp.to grow?

A)Thayer-Martin agar
B)MacConkey agar
C)Phenylethyl alcohol (PEA)
D)Hektoen enteric agar

Question 15

What name is given to the type of hemolysis that produces incomplete hemolysis and a greening discoloration of the medium?

A)b
B)g
C)a
D)k

Question 16

Which medium can be described as a nutritionally rich medium used to grow various microorganisms,either as a broth or as an agar,with or without added blood?

A)Chocolate
B)Colistin,nalidixic acid (CNA)blood
C)Brain-heart infusion (BHI)
D)Thioglycollate broth

Question 17

Reduced O₂ (5% to 10%)and increased CO₂ (8% to 10%)produce an environmental condition that best suits which type of organism?

A)Aerobes
B)Anaerobes
C)Capnophiles
D)Microaerophiles

Question 18

Which category of media can be described as containing some factor or factors that allow colonies of one bacterial species or type to exhibit certain metabolic or culture characteristics that can be used to distinguish them from other bacteria growing on the same agar plate?

A)Enrichment
B)Supportive
C)Selective
D)Differential

Question 19

Organisms that have nutritional needs that are relatively complex and require extra media components to be used for growth are called:

A)fastidious.
B)capnophiles.
C)neutrophils.
D)halophiles.

Question 20

Which category of media can be described as containing nutrients that support the growth of the most nonfastidious organisms without giving any particular organism a growth advantage?

A)Enrichment
B)Supportive
C)Selective
D)Differential

Question 21

A catalase test was performed from a sheep blood agar plate on a colony of streptococci,and bubbling was observed.Which of the following statements explains this discrepancy?

A)Catalase is the inappropriate test to use on colonies of streptococci;therefore the results are invalid.
B)The colony may have been contaminated with sheep red blood cells,causing a false-positive result.
C)The colony was most likely enterococci,not streptococci.
D)No discrepancy is present.Streptococcus is a catalase-positive colony.

Question 22

Oxidative or fermentative media were set up on an organism suspected of being P.aeruginosa.What results would be expected?

A)Yellow in both tubes
B)Green in both tubes
C)Yellow in the open tube and green in the closed tube
D)Green in the open tube and yellow in the closed tube

Question 23

Escherichia coli,a member of the family Enterobacteriaceae,was resistant to the antibiotic vancomycin.Which of the following statements explains this discrepancy?

A)The vancomycin disk has most likely expired.
B)Vancomycin should only be used in viral infections,not bacterial infections.
C)The plate is most likely contaminated with another organism.
D)No discrepancy is present.E.coli is resistant to vancomycin.

Question 24

Characteristic colonial morphology should include all of the following except:

A)glistening.
B)fermenter.
C)pinpoint.
D)entire.

Question 25

Colonial morphology that appears as a "checker" or dipped in the middle with raised edges is termed:

A)flat.
B)convex.
C)umbilicate.
D)variable.

Question 26

Media function testing should include all of the following except:

A)check test organism viability for expected growth.
B)confirm identity of organism using Gram stain.
C)compare performance to previous lot number of media.
D)reincubate for additional time period if no growth is evident.

Question 27

Media function testing should be performed on commercially prepared media when:

A)organisms expected to grow on the media demonstrate growth.
B)daily as required.
C)on all new lots of media.
D)only when the identity and growth characteristics appear abnormal.

Question 28

The limit of detection in the microbiology laboratory is termed:

A)specificity.
B)sensitivity.
C)precision.
D)variation.

Question 29

Quality control from commercially prepared media includes all of the following except:

A)receipt and verification of storage or transportation conditions.
B)visual inspection for discoloration or contamination.
C)pH the media using litmus paper.
D)verification of lot numbers and expiration dates.

Question 30

The most medically important bacteria sought in the medical laboratory are cultivated using incubators with temperatures maintained in what range?

A)35°C to 37°C
B)30°C to 35°C
C)37°C to 39°C
D)25°C to 35°C

Question 31

Primary cultivation of most medically relevant organisms and colonial morphologic interpretations are completed at:

A)6 to 8 hours post inoculation.
B)16 to 18 hours post inoculation.
C)18 to 24 hours post inoculation.
D)16 to 24 hours post inoculation.

Question 32

Generation time can be defined as the:

A)time required for a bacterial population to double.
B)time required for a bacterial population to triple.
C)time required for a bacterial population to quadruple.
D)half-life of bacteria.

Question 33

Interpretation of biochemical tests requires that the microbiologist:

A)correlate the biochemical results with the suspect organism identification.
B)correlate the biochemical results with the preliminary direct smear and staining characteristics.
C)utilize quality control organisms during interpretation to insure proper functioning of the test protocol.
D)all of the above are required.

Question 34

A candle jar is used to cultivate which type of bacteria?

A)Aerobes
B)Anaerobes
C)Capnophiles
D)Microaerophiles

Question 35

Clinical sensitivity in the microbiology laboratory refers to:

A)positive results from patients known to have an infection or disease.
B)percentage of positive results from all patients tested.
C)percentage of patient's that test negative known to have an infection or disease.
D)none of the above answers are correct.

Question 36

A positive pyrrolidonyl arylamidase (PYR)test was observed on a species of Enterococcus.What color should be observed for this reaction?

A)Purple
B)Red
C)Green
D)Pink

Question 37

Media prepared in the laboratory should be tested for quality using all of the following except:

A)check test organism viability for expected growth.
B)confirm identify of organism using Gram stain.
C)check the pH of the media.
D)record lot number.

Question 38

An oxidase test was performed on two organisms for quality control purposes.Pseudomonas aeruginosa and Stenotrophomonas maltophilia tested positive and negative,respectively.Which of the following statements explains this discrepancy?

A)The oxidase reagent is most likely expired.
B)The organisms are most likely old and therefore are not properly reacting.
C)These organisms are poor choices for quality control purposes;both are oxidase-negative organisms.
D)No discrepancy is present.The correct results are obtained.

Question 39

Which of the following organisms grows best at 42°C?

A)Streptococcus pneumonia
B)Haemophilus influenza
C)Neisseria gonorrhoeae
D)Campylobacter jejuni

Question 40

When streaking for isolation and utilizing semi-quantitative methods,the numbers of colonial growth in successive quadrants correlates directly with:

A)the microbiologist's streaking technique.
B)the relative amount of organism present in the original specimen.
C)the ability of the organism to grow on the media.
D)the type of incubation conditions.

Question 41

Colonies that appear white and shinny are also considered:

A)translucent.
B)transparent.
C)mucoid.
D)opaque.