LAB PRACTICAL 2

Which bacteria produces the red pigment in Temperature and Pigment Production?

Serratia marcescens

What is the name of the red pigment produced?

Prodigiosin

At what temperature is the pigment produced?

25

At what temperature is the pigment not produced?

37

What is the temperature range for mesophiles?

20–50

What is the temperature range for psychrophiles?

15°C–20°C

What is the temperature range for thermophiles?

45–80

What is the temperature range for hyperthermophiles?

67°C–105°C

Are E. coli and S. marcescens psychrophiles, mesophiles, thermophiles, or hyperthermophiles?

Mesophiles

What is the optimal growth temperature for Escherichia coli?

37°C

What is the optimal growth temperature for Serratia marcescens?

25°C

What genera are commonly found in the upper respiratory tract?

Streptococcus and Staphylococcus

What does alpha hemolysis look like on BAP?

Greenish zone

What does beta hemolysis look like on BAP?

Clear zone

What do we call bacteria that grow in high salt environments?

Halotolerant

How does water move in a hypertonic solution?

Out of the cell

How does water move in a hypotonic solution?

Into the cell

Which species is halotolerant?

Staphylococcus aureus

What solute was used in this experiment?

Sodium chloride

What is the control concentration of salt?

0.5%, rated as +++

Which type of radiation can penetrate surfaces?

Ionizing radiation

What damage does ionizing radiation cause?

Breaks in DNA

What damage does non-ionizing radiation cause?

Thymine dimers in DNA

Is UV light ionizing or non-ionizing?

Non-ionizing

What is the most lethal UV wavelength?

260 nm

Which side of the plate is the control in a UV test?

The side with more growth

Which species was most tolerant to UV radiation?

Bacillus cereus

What structure allows Bacillus cereus to tolerate UV?

Endospore

What type of media is used in the Kirby-Bauer test?

Mueller-Hinton agar

How do you interpret the zone of inhibition?

Measure and compare to a standard chart

Name one broad-spectrum antibiotic from lab.

Ciprofloxacin

Name one narrow-spectrum antibiotic from lab.

Penicillin

What is the selective agent in MSA?

Salt

What is the differential agent in MSA?

Mannitol fermentation

What does yellow media in MSA indicate?

Ferments mannitol

What is the selective agent in MAC?

Bile salts (selects Gram-negatives)

What is the differential agent in MAC?

Lactose fermentation

What do pink colonies on MAC indicate?

Ferments lactose

What is a coliform?

A lactose-fermenting bacteria

Which bacteria causes most UTIs?

Escherichia coli

Which sex is more prone to UTIs and why?

Females – shorter urethra

What is the threshold for UTI colony count?

Use #bacterial/ml divided by 0.01

What bacteria is used as a fecal indicator?

Escherichia coli

Why is E. coli used as a fecal indicator?

Easy to grow and identify

What is the name of the inverted tube in a fermentation tube?

Durham tube

What sugar is used in the presumptive test?

Lactose

What does gas production in the tube mean?

Possible coliform present

What plate is used for confirmatory coliform testing?

EMB agar

What does E. coli look like on EMB agar?

Metallic green sheen

Name one coliform and one non-coliform from lab.

Coliform = E. coli, Non-coliform = Proteus vulgaris

Are bacteria normally found in blood?

No

What indicates a positive catalase test?

Bubbles

Which genus is catalase positive?

Staphylococcus

Which genus is catalase negative?

Streptococcus

Name the kingdom and organism:

Fungi and Penicillium

Name the kingdom and organism:

Fungi and Rhizopus

Name the kingdom and organism:

Protista and Amoeba Proteus

Name the kingdom and organism:

Protista and Trichomonas Vaginalis

Name the kingdom and organisms:

Protista and Trypanosoma brucei

What is the name of the inverted tube used in a fermentation tube test?

Durham tube.

What does a -/- result mean in a fermentation tube test?

No fermentation, no gas production.

What does a +/- result mean in a fermentation tube test?

Fermentation occurred, but no gas produced.

What does a +/+ result mean in a fermentation tube test?

Fermentation and gas production.

How do you recognize a positive nitrate reduction test?

Red color

How do you recognize a negative nitrate reduction test?

clear color

How do you recognize a positive MR test?

Red color

How do you recognize a negative MR test?

Yellow color

What media is used for the Voges-Proskauer test?

MRVP broth.

What reagent is used for the Voges-Proskauer test?

Barritt’s reagents (A and B).

How do you recognize a positive Voges-Proskauer test?

Red color

How do you recognize a negative Voges-Proskauer test?

yellow color

What media is used for the urease test?

Urea broth.

What indicator is used for the urease test?

Phenol red.

How do you recognize a positive urease test?

Bright pink color.

How do you recognize a negative urease test?

Yellow color

What media is used for the H₂S production test?

Kligler’s Iron Agar.

How do you recognize a positive H₂S test?

Black precipitate forms.

How do you recognize a negative H₂S test?

No black color.

What media is used for the indole test?

Tryptone broth.

What reagent is used for the indole test?

Kovac’s reagent.

How do you recognize a positive indole test?

Red layer on top.

How do you recognize a negative indole test?

No red layer (yellowish top).

What media is used for the citrate utilization test?

Simmons citrate agar.

What indicator is used in the citrate utilization test?

Bromothymol blue.

How do you recognize a positive citrate utilization test?

Blue color.

How do you recognize a negative citrate utilization test?

Green color

What media is used for the phenylalanine deamination test?

Phenylalanine agar.

What reagent is used for the phenylalanine deamination test?

Ferric chloride.

How do you recognize a positive phenylalanine deamination test?

Green color

How do you recognize a negative phenylalanine deamination test?

No green color