Lab 10

A patient has been diagnosed with a wart, a type of primary lesion known as a papule. Describe the appearance of a papule.

 

closed fluid-filled sac positioned deeper in the skin

 

raised lesion containing pus

 

raised solid lesion that isn’t fluid filled

 

small elevated lesion filled with clear fluid

 

raised solid lesion that isn’t fluid filled

A patient has been diagnosed with psoriasis. Psoriasis body lesions are caused by the shedding of the outer layers of the skin, so that the skin surface appears flaky. What is the name of the secondary lesion that the patient is exhibiting?

 

crust

 

purpura

 

petechiae

 

scale

scale

Fred has developed a large blister on his foot. What is the name of the primary lesion that he is exhibiting?

 

bulla

 

macule

 

ulcer

 

pustule

bulla

Jamie gave birth to her first child after 15 hours of labor. The next day, she looked in the mirror and noticed small, red pinpoint-sized spots on her face. Jamie asked the nurse about the spots and he told her that capillaries had burst under her skin during the strenuous delivery. What is the name of the secondary lesions on Jamie’s face?

 

purpura

 

macule

 

maculopapular rash

 

petechiae

petechiae

Rubeola is also known as ___________ and the etiological agent is ____________.

 

roseola/roseola virus

 

German measles/varicella-zoster virus

 

fifth disease/papillomavirus

 

measles/measles virus

measles/measles virus

What type of pathogen causes rubella and rubeola?

 

fungus

 

virus

 

bacteria

 

parasite

 

virus

Rubella is also known as _____________ and the etiological agent is ____________.

 

hand-foot-and-mouth disease/ human parvovirus B19

 

roseola/roseola virus

 

fifth disease/papillomavirus

 

German measles/rubella virus

German measles/rubella virus

Fifth disease is sometimes called _______________ syndrome, because of the appearance of the rash.

 

slapped cheek

 

ulcerative

 

necrotizing

 

scalded skin

slapped cheek

Which maculopapular rash-producing disease is caused by human parvovirus B19

 

impetigo

 

scalded skin syndrome

 

hand-foot-and-mouth

 

fifth disease

fifth disease

What etiological agent causes roseola?

 

human herpes virus 6 and 7

 

Pseudomonas aeruginosa

 

Staphylococcus aureus

 

Candida albicans

human herpes virus 6 and 7

Coxsackievirus 16 and enterovirus 71 are the main viruses that cause ______________ disease.

 

hand, foot, and mouth

 

fifth

 

roseola

 

CRS

hand, foot, and mouth

Which is the etiological agent of smallpox?

 

variola virus

 

herpes simplex

 

human parvovirus B19

 

herpes-zoster

 

variola virus

Which is the etiological agent of chickenpox?

 

enterovirus

 

varicella-zoster virus

 

variola virus

 

parvovirus

 

 

varicella-zoster virus

Reactivation of latent (dormant) viruses cause shingles and reoccurring cold sores. Name these two viruses.

 

varicella and HSV-1

 

enterovirus 71 and herpes-zoster

 

papillomavirus and HSV-2

 

parvovirus B19 and enterovirus 71

 

varicella and HSV-1

Fever blisters are vesicular/pustular rashes that usually occur around the mouth area. What is the etiological agent of fever blisters?

 

HSV-1

 

parvovirus

 

enterovirus

 

papillomavirus

 

HSV-1

What is the etiological agent of necrotizing fasciitis?

 

Staphylococcus epidermidis

 

Streptococcus pyogenes

 

Streptococcus fasciitis

 

Pseudomonas aeruginosa

 

 

Streptococcus pyogenes

What is the etiological agent of scalded skin syndrome and impetigo?

 

Pseudomonas aeruginosa

 

Streptococcus pyogenes

 

Bacillus anthracis

 

Staphylococcus aureus

 

Staphylococcus aureus

You diagnose your patient with cellulitis but do not know if the causative agent is Staphylococcus aureus and Streptococcus pyogenes. You run the following tests and obtain these results:

Blood agar: beta hemolytic
Gram stain: Gram-positive cocci
Catalase: positive
Coagulase: positive

Which is the likely organism that is causing your patient's cellulitis?

 

Staphylococcus aureus

 

Streptococcus pyogenes

 

both organisms would give these results; additional tests are needed

 

neither organism would give these results; additional testing is needed

 

Staphylococcus aureus

Clostridium perfringens is the etiological agent of __________.

 

gas gangrene

 

necrotizing fasciitis

 

toxic shock

 

streptococcal toxic syndrome

 

gas gangrene

MRSA and VRSA are antibiotic resistant forms of which bacteria?

 

Pseudomonas aeruginosa

 

Streptococcus aeruginosa

 

Streptococcus pyogenes

 

Staphylococcus aureus

 

 

Staphylococcus aureus

Cutaneous anthrax is caused by what type of microbe?

 

parasite

 

bacteria

 

virus

 

fungus

bacteria

Otitis externa is caused when the ear is infected with ______________.

 

Clostridium

 

Staphylococcus

 

Streptococcus

 

Pseudomonas

Pseudomonas

The genus of the etiological agent of acne is ______________.

 

Propionibacterium

 

Staphylococcus

 

Pseudomonas

 

Clostridium

Propionibacterium

Tinea corporis means ringworm of the __________.

 

groin

 

head

 

body

 

nails

body

What type of microbe causes cutaneous candidiasis?

 

yeast

 

bacteria

 

parasite

 

virus

yeast

Tinea infections are cause by what type of microbe?

 

bacteria

 

parasite

 

fungus

 

virus

fungus

Conjunctivitis can be caused by bacterial and viral pathogens. What microbe is the main cause of viral conjunctivitis?

 

human papillomavirus

 

HBV

 

adenovirus

 

HIV

adenovirus

What is the etiological agent of ophthalmia neonatorum?

 

Haemophilus influenzae

 

Pseudomonas aeruginosa

 

Chlamydia trachomonas

 

Neisseria gonorrhoeae

 

Neisseria gonorrhoeae

What microbe is the etiological agent of the eye disease, trachoma?

 

Pseudomonas aeruginosa

 

Neisseria gonorrhoeae

 

Haemophilus influenzae

 

Chlamydia trachomatis

 

 

Chlamydia trachomatis

What eye disease is the leading cause of preventable microbial blindness?

 

Acanthamoeba

 

ophthalmia neonatorum

 

Werner’s disease

 

trachoma

trachoma

What genus of bacteria likely caused this greenish-colored lesion?

 

Streptococcus

 

Staphylococcus

 

Pseudomonas

 

Propionibacterium

Pseudomonas

Which picture likely represents viral conjunctivitis?

 

right hand side image

 

left hand side image

 

both images likely represent viral conjunctivitis

 

neither image represents viral conjunctivitis

left hand side image

What disease does this vesicular/pustular rash depict?

 

chickenpox

 

measles

 

smallpox

 

fifth disease

 

smallpox

This image depicts an individual who has cold sores. Whay type of of microbe causes cold sores?

 

fungus

 

virus

 

bacteria

 

protozoa

virus

The image is of a child who has the chickenpox. What type of rash does chickenpox present with?

 

vesicular/pustular rash

 

macular scaling rash

 

maculopapular rash

 

petechial rash

vesicular/pustular rash

What bacterial eye infection that can cause irreversible blindness is depicted in this image ?

 

trachoma

 

herpetic keratitis

 

ophthalmia neonatorum

 

conjunctivitis

trachoma

This greenish lesion is caused by a bacterial virulence factor called ___________.

 

pyocyanin

 

verdechromatinin

 

biliverdin

 

verdoxin

 

pyocyanin

What is the name of the infection caused by Staphylococcus aureus that is depicted in the image?

 

erysipelas

 

scalded skin syndrome

 

necrotizing fasciitis

 

impetigo

 

scalded skin syndrome

What is the name of the infection caused by Streptococcus pyogenes that is depicted in the image?

 

herpetic keratitis

 

cellulitis

 

folliculitis

 

necrotizing fasciitis

 

necrotizing fasciitis

What is the microbe that mainly causes cutaneous candidiasis?

 

Campylobacter jejuni

 

Candida albicans

 

Chlamydia trachomatis

 

Clostridium perfringens

 

Candida albicans

You want to selectively grow bacteria that are part of the skin microbiome in humans. What could you add to the agar that would select for skin inhabitants such as Staphylococcus?

 

a high concentration of citrate

 

a high concentration of sodium chloride

 

a high concentration of lactose

 

a high concentration of bile

 

a high concentration of sodium chloride

MacConkey agar (MAC) is selective and differential. What does the media select for?

 

selects for nonhalotolerant bacteria

 

selects for Gram-positive bacteria

 

selects for Gram-negative bacteria

 

selects for halotolerant bacteria

 

selects for Gram-negative bacteria

MacConkey agar (MAC) is selective and differential. What does the media differentiate?

 

the ability to ferment citrate

 

the ability to ferment lactose

 

the ability to ferment mannitol

 

the ability to ferment urea

 

the ability to ferment lactose

These are the results of three bacterial species inoculated on MacConkey agar. What do the results of sample A indicate?

 

the bacteria are Gram-positive and ferment lactose

 

the bacteria are Gram-negative and cannot ferment lactose

 

the bacteria are Gram-positive and cannot ferment lactose

 

the bacteria are Gram-negative and ferment lactose

 

the bacteria are Gram-negative and cannot ferment lactose

These are the results of three bacterial species inoculated on MacConkey agar. What do the results of sample B indicate?

 

the bacteria are Gram-positive and cannot ferment lactose

 

the bacteria are Gram-negative and ferment lactose

 

the bacteria are Gram-positive and ferment lactose

 

the bacteria are Gram-negative and cannot ferment lactose

the bacteria are Gram-negative and ferment lactose

These are the results of three bacterial species inoculated on MacConkey agar. What do the results of sample C indicate?

 

the bacteria are Gram-positive and ferment lactose

 

the bacteria are Gram-negative and ferment lactose

 

the bacteria are Gram-positive and their ability to ferment lactose cannot be determined from this test

 

the bacteria are Gram-negative and cannot ferment lactose

the bacteria are Gram-positive and their ability to ferment lactose cannot be determined from this test

Citrate agar is a selective medium. What does it select for?

 

selects for bacteria that ferment lactose

 

selects for bacteria that are halotolerant

 

selects for bacteria that can use citrate as a carbon source

 

selects for bacteria that can use citrate as an indicator

selects for bacteria that can use citrate as a carbon source

What enzyme converts citrate into acetic and oxaloacetic acids which are further modified to an alkaline byproduct?

 

lipase

 

citrase

 

convertase

 

acetase

citrase

These are the results of three bacterial species inoculated on citrate agar. Which tube(s) is/are positive?

 

Tube C only

 

Tube A and Tube C

 

Tube B and Tube C

 

Tube A only

Tube A and Tube C

These are the results of three bacterial species inoculated on citrate agar. Which tube(s) is/are negative?

 

Tube B only

 

Tube A only

 

Tube A and Tube C

 

Tube B and Tube C

Tube B only

Methyl red Vogues-Proskauer (MRVP) broth is a differential test. What does it differentiate?

 

methyl red hydrolysis

 

VP hydrolysis

 

glucose fermentation

 

lactose fermentation

glucose fermentation

You are performing a Methyl red Vogues-Proskauer (MRVP) test. After inoculation and incubation, methyl red is added to the tube and the media turns from yellow to red. What does the result indicate?

 

the bacteria ferment glucose to form alkaline byproducts

 

the bacteria ferment glucose to produce a single acid

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria cannot ferment glucose

the bacteria ferment glucose to produce a mix of strong acids

Methyl red Vogues-Proskauer (MRVP). After inoculation and incubation, VP reagents (VPA and VPB) are added to the tube and the media turns from yellow to yellow with a red band on top. What does the result indicate?

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria ferment glucose to produce a single acid

 

the bacteria cannot ferment glucose

 

the bacteria ferment glucose to form alkaline byproducts

the bacteria ferment glucose to form alkaline byproducts

True or False? When performing a Methyl red Vogues-Proskauer (MRVP) test, a bacterial species cannot be positive for both methyl red and Vogues-Proskauer 

 

True

 

False

 

True

You perform a Methyl red Vogues-Proskauer (MRVP) test. What do the methyl red results in Tube 1 indicate?

 

the bacteria cannot ferment lactose to produce a mix of strong acids

 

the bacteria cannot ferment glucose to produce a mix of strong acids

 

the bacteria ferment lactose to produce a single acid

 

the bacteria ferment glucose to produce a single acid

the bacteria cannot ferment glucose to produce a mix of strong acids

You perform a Methyl red Vogues-Proskauer (MRVP) test. What do the methyl red results in Tube 2 indicate?

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria ferment glucose to produce a single acid

 

the bacteria ferment glucose to form alkaline byproducts

 

the bacteria cannot ferment glucose

the bacteria ferment glucose to produce a mix of strong acids

You perform a Methyl red Vogues-Proskauer (MRVP) test. What do the VP results in Tube 1 indicate?

 

the bacteria ferment lactose to produce a mix of strong acids

 

the bacteria cannot ferment lactose to produce a single acid

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria cannot ferment glucose to produce a single acid

the bacteria cannot ferment glucose to produce a single acid

You perform a Methyl red Vogues-Proskauer (MRVP) test. What do the VP results in Tube 2 indicate?

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria ferment glucose to form alkaline byproducts

 

the bacteria cannot ferment glucose

 

the bacteria ferment glucose to produce a single acid

the bacteria ferment glucose to produce a single acid

What are Durham tubes used for when testing an organism in phenol red carbohydrate broth?

 

to detect color change in the tube

 

to check for bacterial growth in the tube

 

to check for gas production during protein fermentation

 

to check for gas production during carbohydrate fermentation

to check for gas production during carbohydrate fermentation

True or False? Phenol red carbohydrate broth contains a base medium and one specific carbohydrate. Because of this, this medium can be used to test for fermentation of different carbohydrates by adding specific carbohydrates to the base medium.

 

True

 

False

True

You inoculate phenol red carbohydrate broth with an isolate from your patient’s sample. After incubation the tube appears yellow. What does this result indicate?

 

the bacteria produce the enzyme decarboxylase

 

the bacteria fermented the carbohydrate in the media

 

the bacteria are unable to ferment the carbohydrate

 

the bacteria produce the enzyme lipase

the bacteria fermented the carbohydrate in the media

These are the results of three patient samples inoculated in phenol red carbohydrate media. Which tube(s) is/are positive for both carbohydrate fermentation and gas production?

 

Tube 2 only

 

Tube 3 only

 

Tube 1 only

 

Tube 1 and Tube 2

Tube 1 only

These are the results of three patient samples inoculated in phenol red carbohydrate media. Which tube(s) is/are positive for carbohydrate fermentation but no gas production?

 

Tube 2 only

 

Tube 1 and Tube 2

 

Tube 3 only

 

Tube 1 only

 

Tube 2 only

These are the results of three patient samples inoculated in phenol red carbohydrate media. Which tube(s) is/are negative for carbohydrate fermentation?

 

Tube 1 only

 

Tube 1 and Tube 2

 

Tube 2 only

 

Tube 3 only

Tube 3 only

These are the results of three patient samples inoculated in phenol red carbohydrate media. Which tube(s) is/are positive for carbohydrate fermentation?

 

Tube 2 only

 

Tube 3 only

 

Tube 1 and Tube 2

 

Tube 1 only

 

Tube 1 and Tube 2

Urea broth is a differential medium. What does it differentiate?

 

urea hydrolysis

 

urea formation

 

urea release

 

urea fermentation

 

urea hydrolysis

What enzyme hydrolyzes urea into ammonia, carbon dioxide, and water?

 

fermentase

 

protease

 

urease

 

carboxylase

 

urease

These are the results of two patient samples inoculated in urea broth and incubated overnight. Which tube(s) is/are urease positive?

 

neither Tube 1 nor Tube 2

 

both Tube 1 and Tube 2

 

Tube 1 only

 

Tube 2 only

Tube 2 only

These are the results of two patient samples inoculated in urea broth and incubated overnight. Which tube(s) is/are urease negative?

 

Tube 2 only

 

neither Tube 1 nor Tube 2

 

Tube 1 only

 

both Tube 1 and Tube 2

 

Tube 1 only

Nitrate broth is a differential medium. What does it differentiate?

 

nitrate reduction

 

bile fermentation

 

bile reduction

 

nitrate fermentation

nitrate reduction

These are the results of two patient samples inoculated in nitrate broth. After an overnight incubation nitrate reagents A and B were added to the tubes. What interpretations can you make concerning Tube A?

 

the organism can reduce nitrite to ammonia or nitrogen gas

 

the organism can reduce nitrate to nitrite then further reduce nitrite to ammonia or nitrogen gas

 

the organism cannot reduce nitrate

 

the organism can reduce nitrate to nitrite

the organism can reduce nitrate to nitrite

These are the results of two patient samples inoculated in nitrate broth. After an overnight incubation nitrate reagents A and B were added to the tubes. What, if anything, should be done with Tube B

 

methyl red should be added to determine lactose fermentation

 

none of the answers are correct

 

zinc should be added to determine the presence or absence of nitrate

 

the sample is negative for nitrate reduction, so no further testing is required

 

zinc should be added to determine the presence or absence of nitrate

True or False? After the addition of nitrate reagents A and B to an inoculated and incubated sample, the media remains yellow. This should be interpreted as negative for nitrate reduction.

 

True

 

False

False

These are the results of two patient samples tested for nitrate reduction. Both samples remained yellow after the addition of nitrate reagents A and B. Next, zinc was added to both tubes. What do the results of Tube A indicate?

 

the organism reduced nitrite to ammonia and nitrogen gas only

 

the organism reduced nitrate to nitrite, then further reduced nitrite to ammonia or nitrogen gas

 

the organism cannot reduce nitrate

 

the organism reduced nitrate to nitrite only

the organism cannot reduce nitrate

These are the results of two patient samples tested for nitrate reduction. Both samples remained yellow after the addition of nitrate reagents A and B. Next, zinc was added to both tubes. What do the results of Tube B indicate?

 

the organism cannot reduce nitrate

 

the organism reduced nitrate to nitrite only

 

the organism reduced nitrate to nitrite, then further reduced nitrite to ammonia or nitrogen gas

 

the organism reduced nitrite to ammonia and nitrogen gas only

the organism reduced nitrate to nitrite, then further reduced nitrite to ammonia or nitrogen gas

You test two patient samples for nitrate reduction. After inoculation and incubation, you add nitrate reagents A and B to both tubes. Tube A remained yellow and tube B turned red. Next you add zinc to Tube A and it remains yellow. What do the results of these samples indicate?

 

both organisms are positive for nitrate reduction

 

neither organism is positive for nitrate reduction

 

organism B is positive for nitrate reduction, but organism A is negative for nitrate reduction

 

organism A is positive for nitrate reduction, but organism B is negative for nitrate reduction

both organisms are positive for nitrate reduction

Sulfur indole motility (SIM) agar is a differential medium. What does it differentiate? Select all that apply

 

indole production

 

bacterial motility

 

indole hydrolyzation

 

hydrogen sulfide production

 

lactose fermentation

indole production 
bacterial motility
hydrogen sulfide production

These are the results of four organisms inoculated in SIM agar. After an overnight incubation, Kovac's reagent was added to all tubes. Match the tube designated in the left-hand column to their test results from the dropdown menu

A

B

C

D

 

indole negative/hydrogen sulfide negative
indole positive/hydrogen sulfide negative
indole negative/hydrogen sulfide positive
indole positive/hydrogen sulfide positive

 

indole negative/hydrogen sulfide negative
indole positive/hydrogen sulfide negative
indole negative/hydrogen sulfide positive
indole positive/hydrogen sulfide positive

Salmonella typhimurium is indole negative and hydrogen sulfide positive. Which of the SIM agar results reflect these properties?

 

Tube 3

 

Tube 2

 

Tube 1

 

Tube 4

 

Tube 3

Klebsiella pneumoniae is indole negative and hydrogen sulfide negative. Which of the SIM agar results reflect these properties?

 

Tube 4

 

Tube 1

 

Tube 3

 

Tube 2

 

Tube 2

Escherichia coli is indole positive and hydrogen sulfide negative. Which of the SIM agar results reflect these properties?

 

Tube 3

 

Tube 1

 

Tube 4

 

Tube 2

Tube 1

Proteus vulgaris is indole positive and hydrogen sulfide positive. Which of the SIM agar results reflect these properties?

 

Tube 4

 

Tube 1

 

Tube 3

 

Tube 2

Tube 4

Match the microbiological test in the left-hand column to its function from the dropdown menu.

MacConkey agar
citrate agar
urea broth
nitrate broth
phenol red sucrose broth
SIM agar

 selects for Gram-negative bacteria; differentiates lactose fermentation

 selects for citrase-producing bacteria

 differentiates urease production

 detects nitrate reduction

 differntiates sucrose fermentation

 detects the breakdown of tryptophan

MacConkey agar

 selects for Gram-negative bacteria; differentiates lactose fermentation

citrate agar

 selects for citrase-producing bacteria

urea broth

 differentiates urease production

nitrate broth

 detects nitrate reduction

phenol red sucrose broth

 differntiates sucrose fermentation

SIM agar

 detects the breakdown of tryptophan

You inoculate nitrate broth tubes with two patient samples. After incubation, you add nitrate reagents A and B, and both tubes turn red. Interpret these results.

 

both organisms reduce nitrate to nitrite

 

neither organism can reduce nitrate

 

both organisms reduce nitrate to nitrite, and then further reduce nitrite to ammonia or nitrogen gas

both organisms reduce nitrate to nitrite

These are the results of the nitrate test after the addition of nitrate reagent A and B. Which tube(s) should be further tested with zinc?

 

positive control 2 and negative control

 

positive control 2 only

 

zinc should be added to all four tubes

 

positive control 1 and outbreak sample

positive control 2 and negative control

These are the results of a nitrate test after the addition of reagents A and B to all tubes, then adding zinc to only positive control 2 and the negative control. Determine if the each control listed in the left-hand column reacted as expected in this test. Choose yes or no from the dropdown menu.

1. Positive control 1: inoculated with Escherichia coli which reduces nitrate to nitrite.

2. Positive control 2: inoculated with Pseudomonas putida which reduces nitrate to nitrite then further reduces nitrite to ammonia or nitrogen gas.

3. Negative control: inoculated with Alcaligenes faecalis which cannot reduce nitrate. 

positive control 1

positive control 2

negative control

positive control 1

 yes

positive control 2

 yes

negative control

yes

These are the results of a nitrate test after the addition of reagents A and B to all tubes, then adding zinc to only Positive control 2 and the negative control. All three controls reacted as expected. What are the patient’s results?

 

the patient sample contains an organism that reduces nitrate to nitrite, then further reduces nitrite to ammonia or nitrogen gas

 

the patient sample contains an organism that cannot reduce nitrate to nitrite

 

the patient sample contains an organism that reduces nitrate to nitrite

the patient sample contains an organism that reduces nitrate to nitrite

Which detection reagent should be added to SIM tubes after incubation and before interpreting results?

 

nitrate reagents A and B

 

Barritt’s reagents A and B

 

Kovac’s reagent

 

methyl red

Kovac’s reagent

These are the results of an outbreak patient’s sample on SIMs agar. After an overnight incubation, Kovac’s reagent was added. The positive and negative controls reacted as expected. What are the patient’s results?

 

the patient sample contains an organism that doesn’t produce indole or hydrogen sulfide

 

the patient sample contains an organism that produces indole, but doesn’t produce hydrogen sulfide

 

the patient sample contains an organism that doesn’t produce indole, but produces hydrogen sulfide

the patient sample contains an organism that doesn’t produce indole or hydrogen sulfide

These are the results of an outbreak patient’s sample inoculated on MacConkey (MAC) agar and incubated overnight. The positive and negative controls reacted as expected. What can you conclude from the patient’s results?

 

the patient sample contains an organism that cannot grow on MAC

 

the patient sample contains an organism that is positive for growth but doesn’t ferment lactose

 

the patient sample contains an organism that is positive for growth and ferments lactose

the patient sample contains an organism that is positive for growth but doesn’t ferment lactose

These are the results of a patient sample inoculated in methyl red Vogues-Proskauer broth. After an overnight incubation, methyl red was added to the tubes. What can you conclude from the patient’s results

 

the bacteria ferment glucose to form alkaline byproducts

 

the bacteria ferment glucose to produce a single acid

 

the bacteria ferment glucose to produce a mix of strong acids

 

the bacteria cannot ferment glucose

 

the bacteria ferment glucose to produce a mix of strong acids

These are the results of a patient sample inoculated in methyl red Vogues-Proskauer broth. After an overnight incubation, VP reagents were added to the tubes. What can you conclude from the patient’s results

 

the bacteria cannot ferment glucose to produce a mix of strong acids

 

the bacteria cannot ferment glucose to produce a single acid

 

the bacteria cannot ferment glucose

 

the bacteria ferment glucose to form alkaline byproducts

the bacteria cannot ferment glucose to produce a single acid

These are the results of a Methyl red Vogues-Proskauer (MRVP) test. The controls react as expected. Interpret the patient’s results.

 

methyl red positive, Vogues-Proskauer negative

 

methyl red positive, Vogues-Proskauer positive

 

methyl red negative, Vogues-Proskauer positive

 

methyl red negative, Vogues-Proskauer negative

methyl red positive, Vogues-Proskauer negative

These are the results of a urea test. The controls react as expected. Interpret the patient’s results.

 

urease negative, negative for lactose fermentation (urea negative, negative for fermentation)

 

urease negative only (urea test negative)

 

urease positive, positive for lactose fermentation (urea positive, positive for fermentation)

 

urease positive only (urea teat positive)

 

urease negative only (urea test negative)

These are the results of a citrate test. The controls react as expected. Interpret the patient’s results.

 

the organism can utilize citrate as a carbon source (citrate positive)

 

the organism can utilize citrate as a carbon source (citrate negative)

 

the organism cannot utilize citrate as a carbon source (citrate positive)

 

the organism cannot utilize citrate as a carbon source (citrate negative)

the organism cannot utilize citrate as a carbon source (citrate negative)

These are the results of a phenol red carbohydrate test. The carbohydrate added to the media is trehalose. The controls react as expected. Interpret the patient’s results.

 

the organism can ferment trehalose and gas is produced

 

the organism can ferment trehalose and gas is not produced

 

the organism cannot ferment trehalose and gas is produced

 

the organism cannot ferment trehalose and gas is not produced

the organism can ferment trehalose and gas is not produced

These are the results of a phenol red carbohydrate test. The carbohydrate added to the media is sucrose. The controls react as expected. Interpret the patient’s results.

 

the organism can ferment sucrose and gas is not produced

 

the organism cannot ferment sucrose and gas is produced

 

the organism can ferment sucrose and gas is produced

 

the organism cannot ferment sucrose and gas is not produced

the organism cannot ferment sucrose and gas is not produced

Compare Escherichia coli and the outbreak patient sample. Why can't E. coli be the bacteria that was isolated from the patient?

 

E. coli cannot ferment sucrose and the patient’s bacterium can ferment sucrose

 

E. coli can use citrate as carbon source and the patient’s bacterium cannot

 

E. coli can hydrolyze urea and the patient’s bacterium cannot

 

E. coli can ferment lactose and the patient’s bacterium cannot

 

E. coli can ferment lactose and the patient’s bacterium cannot

Compare Salmonella enteritidis and the outbreak patient sample. Why can't S. enteritidis be the bacteria that was isolated from the patient?

 

S. enteritidis reduces nitrate and the patient’s bacterium cannot

 

S. enteritidis cannot produce urease and the patient’s bacterium produces urease

 

S. enteritidis produces hydrogen sulfide and the patient’s bacterium cannot

 

S. enteritidis cannot ferment sucrose and the patient’s bacterium can ferment sucrose

S. enteritidis produces hydrogen sulfide and the patient’s bacterium cannot

The table compares patient test results to test results obtained from known bacteria. Which bacteria is likely the cause of your patient’s illness?

NOTE: You will see similar questions on the upcoming Lab Final Review and Lab Final Exam

 

Escherichia coli

 

Proteus mirabilis

 

Klebsiella pneumoniae

 

Citrobacter freundii

 

Salmonella enteritidis

 

Shigella flexneri

Shigella flexneri