Lab 3 Flashcards by Jade Ring

Streptococcus ID and Isolation

Blood agar was used

What kind of medium is it?

What technique did we use with the plate?

Enrichment and differential

Quadrant Streak Isolation

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We swabbed our throats looking for Streptococci

What are the possible results

Alpha: Green area. Reduced hemolysis around colonies Pin head sized.
Possibly Streptococcus mitis / Streptococcus pneumonia

Beta: Clear Zones under and around colony RBC Destroyed Pin head.
Possibly: Staph aureus / Streptococcus pyogenes

Gamma: No hemolysis Larger colonies
Possibly: Staphylococcus epidermidis

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Alpha hemolysis: Describe
Possible species

Green area. Reduced hemolysis around colonies Pin head sized.
Possibly Streptococcus mitis / Streptococcus pneumonia

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Beta hemolysis: Describe
Possible species

Clear Zones under and around colony RBC Destroyed Pin head.
Possibly: Staph aureus / Streptococcus pyogenes

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Gamma hemolysis

No hemolysis Larger colonies
Possibly: Staphylococcus epidermidis

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In blood agar why do we stab the agar?

To allow less oxygen to encourage growth of bacteria

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Mannitol contains how much sodium chloride

7.5%

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What are fomites

Inanimate objects that may contain bacteria

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Which species cause Beta lysis ( Clear Zone)
Does this destroy the blood cell

Staphylococcus aurus
Streptococcus pyogenes

Yes

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Which species causes Alpha lysis ( Green or brown)
Is this destruction of the RBC

Streptococcus mitis
Streptococcus pneumonia

Partial

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Which species causes Gamma lysis(No color change)
Does this destroy it?

Staphylococcus epidermidis
No

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What kind of media is Mannitol Salt plate?
How so?
Which type of bacteria were we looking for?

Selective 7.5% NaCl selects for Staphylococcus

Differential: Mannitol when fermented bacteria produce acid which turn pH indicator Phenol red to a Yellow color

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What does a Pink / Yellow color on Mannitol Salt Plate indicate?

Pink no break down of sugar
Yellow break down of sugar

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Type of bacteria we were looking for in the blood agar experiment with the quadrant Streak taken from throat

Streptococci

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Type of bacteria and medium used in the Nose, Formite, and Unknown.

What was the differential process

What was the selective process

Type of medium used

Staphylococci

Breaking down of the sugars (mannitol)

7.5% salt

Mannitol Salt plate

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The Mannitol Salt plate was used for this bacteria

The blood agar was used for this bacteria

In the earlier experiments NOT the unknown

Staphylococci

Streptococci

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Mannitol Salt Plate

Used to ID this type of Bacteria

Yellow = this bacteria
Pink = this bacteria

Staphylococcus

Staphylococcus aureus (Breakdown)

Staphylococcus epidermidis (No Breakdown)

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What does DSLB and SSLB mean and which 2 species, know as what, was it looking for?

DSLB is 10ml “test water sample”
SSLB is 1 & .1 ml “test water sample

Intestinal bacteria “ E. coli & Enterobacter aerogenes” Coliforms

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What is the name of the mechanism in which the CO² was collected in while looking for Coliforms

Durham Tube

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The Presumptive test for fecal contamination has 3 indicators for a positive test, name them

Color change from Pink to Yellow
Cloudy growth
Gas bubble in Durham tube (due to Break down of Lactose)

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10ml pipette is this color
1ml pipette is this color

Green
Blue

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What were the two types of agars we inoculated in the Bacterial Water Exam

What are the positive results for coliforms?

Levine EMB agar: Coliforms produce Large Blue-Black colonies with a green metalic sheen for E coli

Endo agar: Coliform colonies produce Pink to Rose-Red colonies.

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What is the gram status and differential mediums used for coliforms?

Gram-negative
Lactose fermentation Presumptive
Levine EMB & Endo agar Confirmed

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The Presumptive test for Coliforms: is also used to determine this ______ which is the amount of coliforms present per 100ml water

MPN

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Initial dilution of lettuce given to class

1:10

How many mls were transferred from Inital sample to A in lettuce dilution What was As dilution How many mls were transferred from A to B What was its total dilution

. 1ml 1:1000 .1ml 100,000

4 plates were used in the lettuce sample to grow bacteria What is the dilution if .1 ml is platted from 1:1,000 dilution

10,000

How much does 1ml of water weigh

1 gram

Why are EMB and endo agar used as a confirmation test

They select for Gram-negative and don't allow Gram-positive to grow

Citrobacter, Enterobacter, Klebsiella, Escherichia are all this type of microbe

Coliforms

Type of plate / plate count used in bacterial count of a food product

Standard methods agar Heterotrophic plate count

The medium hetrotrophic gives what nutrient to support the growth of bacteria

Organic carbon

EMB agar is selective for gram-negative bacteria. How does it do this? How does it differentiate?

The dye methylene blue inhibits the growth of gram positive Selective Eosin and methylene blue are pH indicator dyes when lactose gets broken down it produces acid Differential

What does EMB stand for in the agar

Eosin methylene blue agar

The selectivity of _____ is due to the sodium sulfite/basic fuchsin combination which results in the suppression of gram-positive microorganisms.

Endo agar

Which metabolic process makes EMB and endo agar differential

Lactose fermentation

The differential ingredient in MSA is... The selective ingredient is... The acidity of the media will cause the pH indicator, ______, to turn yellow.

The sugar Mannitol 7.5 % NaCl Phenol Red

In the lettuce experiment with 4 plates If .1 ml from B (1: 100,000) is plated what will the concentration be

1,000,000

In the unknown Gram Positive Cocci get put on this type of plate Possible outcomes Rods on this type of plate

MSA: Cocci Pink Staphylococcus epidermidis(pink) Yellow Staphylococcus aureus (yellow) Blood agar: Rods Beta hemolysis: Bacillus cereus Gama hemolysis: Bacillus megaterium

Unknown Gram positive Rods got plated on what? What were the 2 possible outcomes and species.

Blood agar Beta hemolysis: Bacillus cereus Gama hemolysis: Bacillus megaterium

Unknown experiment Cocci Gram-positive got this type of plate 2 possible outcomes

MSA plate Mannitol Salt plate Pink: Staphylococcus epidermidis Yellow: Staphylococcus aureus

If 2 plates were done in the Unknown Which type of staining process was done. Which stain was used

Simple Stain Air dry Heat fix Methylene blue 1 minuto

S aureus, S epidermidis, B megaterium, B cereus All have this gram staining property

Gram positive

Alcaligenes faecalis, Escherichia coli, Enterobacter aerogenes, Proteus vulgaris All have this gram staining property

Gram negative

Thioglycolate is used to determine this in the Unknown Gram negative

Oxygen requirements

In the gram negative Thycogyclate which was the: Obligate aerobe Facultative anaerobe

Alcaligenes faecalis ( Obligate Aerobic) Escherichia coli, Enterobacter aerogenes, Proteus vulgaris (Facultative anaerobe)

Gram negative Unknown Citrate agar Which color indicates no citrate utilization Which indicates use of citrate Inoculation instrument

Green = (-) or no use of citrate Blue/Black = (+) break down of citrate Loop

Which gram negative species use citrate turning the medium Blue/Black Which don't use citrate leaving the agar a Green

Enterobacter aerogenes (Blue/ Black) Use citrate E. coli, Proteus vulgaris, Alcaligenes faecalis (Green) Don't use citrate

In the gram negative Unknown Urease Production is measured in the Urea Slant Agar Which type of inoculation instrument was used. What is a Negative/ Positive indicator of Urease Production

Loop Orange / Pink: Negative Flaming Pink: Positive

On the Gram negative Unknown Thioglycolate & Motility Media Both used this instrument to inoculation

Straight needle

Gram negative Unknown Urease Production These bacteria produced Urease with a Flamming Pink Result These bacteria did not produce Urease with a light pink / orange Result

Proteus Vulgaris Produced Urease Flamming Pink Alcaligenes faecalis, E coli, Enterobacter aerogenes. No Urease Production light orange

How were the caps adjusted in the Gram-negative unknown

Loose cap

Motile organisms are able to move about the semi-solid medium resulting in a ______ growth throughout the medium. Non-motile organisms will remain isolated at the inoculation point and will appear as pink or red growth along the stab line. Which bacteria were motile

pink or red diffuse All

Thioglycolate is an enriched non-selective broth T or F

Motility test media is which type of media

Differential

This type of (Streaking) is done on the MSA plate: Blood agar:

MSA: Zig zag Blood agar: Quadrant Isolation Streak

This is the type of plate used in the Handwashing lab is a general purpose plating medium used for the isolation, cultivation, and maintenance of a variety of fastidious and non- fastidious microorganisms.

Tryptic Soy Agar (TSA)

Normal flora from handwashing on Tryptic Soy Agar (TSA) Plate had this appearance Possible pathogens this appearance

Small white dots (Normal flora) Larger Red (Possible Pathogen)

Type of (Streaking) used on Levine EMB & endo agar

Quadrant streak

How were the counts in the Bacterial food count done

CFU

What is the definitive test for S. aureus

Colagulase

Which gram positive bacteria are positive on a TSA (blood agar plate)

Both Staphylococcus Aureus ( Beta hemolysis) (Giant colonies)& Staphylococcus epidermidis (Gamma hemolysis)(small white colonies) Bacillus megaterium ( Gamma hemolysis) & Bacillus cereus (Beta hemolysis)

Which gram positive bacteria are positive on MSA plate. Which are negative

Positive: Staphylococcus aureus (Yellow-breakdown) Staphylococcus epidermidis (Pink-no breakdown but growth) Negative Bacillus megaterium & Bacillus cereus The 7.5 salt kills them

_____ broth is the medium we used as a presumptive test for coliform bacteria / water test

DSLB / SSLB Double/ Single Strength Lactose Broth

Which unknown organisms will grow on PEA (phenyethyl alcohol agar).

Will Grow: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus megaterium, Bacillus cereus Will not grow: Alcaligenes faecalis, Enterobacter aerogenes, Escherichia coli, Proteus vulgaris

Which unknown will grow in EMB agar (Eosin Methylene Blue)

Gram-negative will Grow: Alcaligenes faecalis, Escherichia coli, Enterobacter aerogenes, Proteus vulgaris Gram-positive will not grow: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus megaterium, Bacillus cereus

Which medium grew gram-positive Cocci Bacillus

Cocci: MSA (Mannitol Salt plate) Bacillus: Blood Agar