microbio 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.

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?

scale

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

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?

petechiae

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

measles/measles virus

What type of pathogen causes rubella and rubeola?

virus

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

German measles/rubella virus

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

slapped cheek

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

fifth disease

What etiological agent causes roseola?

human herpes virus 6 and 7

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

hand, foot, and mouth

Which is the etiological agent of smallpox?

variola virus

Which is the etiological agent of chickenpox?

varicella-zoster virus

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

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

What is the etiological agent of necrotizing fasciitis?

Streptococcus pyogenes

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

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

Clostridium perfringens is the etiological agent of __________.

gas gangrene

MRSA and VRSA are antibiotic resistant forms of which bacteria?

Staphylococcus aureus

Cutaneous anthrax is caused by what type of microbe?

bacteria

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

Pseudomonas

The genus of the etiological agent of acne is ______________.

Propionibacterium

Tinea corporis means ringworm of the __________.

body

What type of microbe causes cutaneous candidiasis?

yeast

Tinea infections are cause by what type of microbe?

fungus

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

adenovirus

What is the etiological agent of ophthalmia neonatorum?

Neisseria gonorrhoeae

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

Chlamydia trachomatis

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

trachoma

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

Pseudomonas

Which picture likely represents viral conjunctivitis?

left hand side image

What disease does this vesicular/pustular rash depict?

smallpox

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

virus

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

vesicular/pustular rash

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

trachoma`

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

pyocyanin

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

scalded skin syndrome

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

necrotizing fasciitis

What is the microbe that mainly causes cutaneous candidiasis?

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 sodium chloride

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

selects for Gram-negative bacteria

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

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-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-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 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 can use citrate as a carbon source

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

citrase

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

Tube A and Tube C

These are the results of four organisms inoculated in SIM agar. After an overnight incubation, Kovac's reagent was added to all tubes.

what is tube A

indole negative

hydrogen sulfide negative

These are the results of four organisms inoculated in SIM agar. After an overnight incubation, Kovac's reagent was added to all tubes.

what is tube b

indole positive

hydrogen sulfide negative

These are the results of four organisms inoculated in SIM agar. After an overnight incubation, Kovac's reagent was added to all tubes.

what is tube c

indole negative

hydrogen sulfide positive

These are the results of four organisms inoculated in SIM agar. After an overnight incubation, Kovac's reagent was added to all tubes.

what is tube d

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

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

tube 2

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

tube 1

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

tube 4

macconkey agar

selects for gram negative bacteria

differentiate lactose fermentation

citrate agar 

selects for citrase-producing bacteria 

urea broth

differentiates urease production

nitrate broth

detects nitrate reduction

phenol red sucrose broth

differentiates 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

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

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. 

1. yes

2. yes

3. 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

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

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

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 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 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 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

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

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 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 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 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 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 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?

Shigella flexneri

True or False? Bacteria that are oxidase positive are aerobic and can use oxygen as a terminal electron acceptor in aerobic respiration.

true

In which step of aerobic respiration would you find cytochrome c oxidase?

electron transport chain

Which of the bacteria are positive for cytochrome c oxidase?

Neisseria cinerea only

Which of the bacteria are negative for cytochrome c oxidase?

both Serratia marcescens and Shigella flexneri

Proteus vulgaris is oxidase negative. Which swab has results indicative of P. vulgaris?

swab B only

Neisseria gonorrhoeae is oxidase positive. Which swab has results indicative of N. gonorrhoeae?

swab A only

Which of the following could cause an erroneous cytochrome C oxidase test result? Select all that apply

media high in carbohydrates

selective media