Microbiology lab practical review 1

1. Microbiology
Practical 1
Ilana Kovach
Live, laugh, love and learn
“There is no threshold limit to the capacity of the
human mind – the girl who made this crazy
powerpoint”

2. Gram Positive Cocci
Staphylococcus aureus(BSL-2)
Staphylococcus xylosus (BSL-1)
Staphylococcus epidermidis(BSL-1)
Streptococcus pyogenes(BSL-2)
Streptococcus mutans (BSL-1)
Streptococcus zooepidemicus (BSL-2)
Enterococcus faecalis (BSL-2)
Micrococcus luteus (BSL-1)
Gram Positive Rods
Bacillus cereus (BSL-2)
Bacillus subtilis (BSL-1)
Bacillus megaterium (BSL-1)
Bacillus stearothermophilus (BSL-1)
Clostridium sporogenes (BSL-1)
Diptheroids
Mycobacterium smegmatis (BSL-1)
Gram Negative Rods
Alcaligenes faecalis (BSL-1)
Enterobacter aerogenes (BSL-1)
Escherichia coli(BSL-1)
Morganella morganii(BSL-2)
Pseudomonas aeruginosa(BSL-2)
Pseudomonas fluorescens(BSL-1)
Serratia Marcescens(BSL-1)
Gram Positive Cocci
Neisseria species (G- negative cocci)
Saccharomyces cerevisiae(BSL-1)

3. Week 1
Microscopy
Gram Stain

4. Aseptic Technique “Pathogen free environment”
Beginning of Lab
1.) Put away Belongings
2.) Clean Tables
3.) wash Hands
4.) Tie back long Hair
BSL-1 (Low risk) Doesn’t cause disease in healthy humans
*Lab Coats
BSL-2 (moderate risk) associated in moderate disease in
humans
*Lab coats & Disposable Gloves
 Googles required when using chemicals (Example Gram
staining)
Opportunistic doesn’t typically cause disease in healthy
adults, but may in immunocompromised adults or children
4 potential routes of Exposure:
1. Absorption Through skin or mucous membranes
2. Inhalation
3. Ingestion
4. Inoculation

5. Bacterial Specimen info:
Name of Microorganism
Your name/Initials
Date
Tape labels are required for media in Test Tubes (White)
Carry Test tubes  Incubator
Test Tube rack (M/W class Yellow)
Tape petri dishes on both ends before carrying them to
incubator
Disposal of contaminated items:
Petri plates  Biohazard waste
Glass pipettes  Pipette discard box
Test tubes  Test tube discard bin
Glass slides SHARPS box
Gloves  Biohazard waste
Plastic ware  Biohazard waste
Broken test tubes  SHARPS box
Regular Trash uncontaminated items & Paper towels
End of Lab disinfect tables & wash your hands

6. Ex. 1 Microscopy
Bacillus
Staphylococcus
Saccharomyces

7. Arrangement of Prokaryotic Cells
Cocci  multiple Planes Bacilli  single Planes
Coccus Diplococci Staphylococci
Streptococci Sarcina
Tetrad
Coccobacillus Bacilli
Diplobacilli Palisades
Streptobacilli

8. 3 main Prokaryotic Cell shapes
Cocci
Spirals
1. Spirochetes  Flexible
2. Spirillum  Inflexible
Rods “Bacillis”
Coccobacillus “Short Rod”
Vibrio “Curved Spiral”
Pleomorphic
“Does not Have a shape”

9. Oculars
Arm
Objective
Lenses
Nose Piece
Body
Base
Fine
Focus
Coarse
focus
Stage
Light Source
(Illuminator)
Condenser & Iris
Diaphragm
(underneath
Microscope Skills
Oil Immersion: Apply between 40x and 100x
Specimen in
Field of View & in Focus: Trick Bring the Edge of the slide into
focus should appear as 3-D
Light Level: light source (Illuminator)switchturns light source at base;
Condenser collects& concentrates light from the illuminator& directs
it to the irisdiaphragm
Clean Up: oil Immersioncleaned from all lenses & Stage
Slide removed, Placed in 4x, Stage Lowered & Centered.
Identify: Gram positive/Negative,Morphology, Total Magnification

10. Ex. 2 Gram Stain
Escherichia Coli “Rod”
 Gram Negative (Pink)
Bacillus subtilis “Rod”
 Gram Positive (Purple)
Staphylococcus Xyolus “Spherical”
 Gram Positive (Purple)

11. Gram Positive Gram Negative
Teichoic Acid
Lipoteichoic Acid
Peptidoglycan Layer
(cell wall)
Cytoplasmic
Membrane
Integral Protein
Peptidoglycan Layer of
(cell wall)
Cytoplasmic
Membrane
Outer
Membrane of
Cell
Porin Periplasmic
Space
Lipopolysaccharide Layer
(LPS) Containing Lipid A

12. Heat fix
 Kills the microbes
 Makes microbes more
permeable to stains
 Fixes microbes to slide
Why dry before Heat fixing?
If heated right after the water would cause the smear to
overheat & denature some features in the stain.
Bacterial Smear
A smear is a small volume (Loopful) of specimen- containing
medium that is spread (smeared) onto microscope slide

13. Week 2
Capsule Stain
Acid Fast Stain
Endospore Stain

14. Ex. 3 Capsule Stain
 Klebsiella Pneumoniae
 Capsule is Halo around the
cell
Heat & water
would dislodge Capsule from
bacteria (polysaccharide,
Polypeptide, Glycoprotein) Need t
Air Dry

15. Ex. 4 Acid-Fast Stain
 Myobacterium smegmatis (Acid Fast
Cells)
 Bacillus Subtilis (Non Acid fast cells)

16. Ex. 5 Endospore Stain(Bacillus & clostridium)
 Bacillus Subtilis as Vegatative Cells
 Bacillus Subtilis Vegetative cells with Endospore inside
 Bacillus Subtilis as a Free Spore

17. Endospores
(Bacillus & Clostridium)
Outer Spore Coat (Exosporium)
Outer Spore Coat
(Exosporium)
Spore Coat
Outer
Membrane
Cortex
Spore Core
Inner
Membrane

18. Week 3
Culture Transfer Technique
Isolation of Pure Cultures
Viable Plate Count
Culture Characteristics

19. Ex. 6 Culture Transfer Technique
 Broth  Deep (Needle Single
Slob)
 Broth  Slant (Loop Zig Zag)
 Slant  Broth (Loop Swish)
All Caps loose but secure
Incubate 25º
SlantSlant Broth BrothBrothDeep

20. Results

21. Ex. 7 Pure Isolation Cultures
Ilana Kovach (09/02/15) Serratia
Marcescens & Escherichia Coli
21
34
 Incubate upside down to prevent
condensation at 25º
 Tape both ends
Warning: Sterilize
after each streak
& DO NOT reapply
more bacteria!!!

22. Results
The purpose of this
method is to isolate pure
colonies of Bacteria

23. Ex. 8 Viable Plate count
10-1 10-2 10-3 10-4 10-5 10-6 10-7
10-810-710-6

24. Results
10-8
10-7
More than 300 =TNTC
Less than 30 = TFTC

25. Ex. 9 Growth Characteristics of Colonies & Broth Cultures
Micrococcus
Luteus
Size: 1.5mm
Pigmentation: Cream
Form: Circular
Elevation: Flat
Margin: entire
Size: 5mm
Pigmentation: Yellow
Form: Circular
Elevation: Umbonate
Margin: Entire
Size: 2mm
Pigmentation: Green
Form: Irregular
Elevation: Pulvinate
Margin: Erose

26. Ex. 9 Growth Characteristics of Colonies & Broth Cultures
Escherichia
Coli
Bacillus
Cereus
Size: 4mm
Pigmentation: Cream
Form: Irregular
Elevation: Convex
Margin: Undulate
Size: 3mm
Pigmentation: Cream
Form: Filamentous
Elevation: Flat
Margin: Erose

27. Form
Elevation
Margin

28. Name of
Specimen in
Broth
Growth Pattern Descriptions
Bacillus Cereus Little Sediment; Mostly Fine
Mycobacterium
Smegmatis
Sediment
Pseudomonas
Aeruginosa
Sediment
Saccromyces
Cerevisiae
Little Sediment; Mostly fine
Serratia
Marscens
Fine

29. Sediment:
Myobacterium Smegmatis
Pseudomonas Aeruginosa
Mostly Fine/little
Sediment:
Bacillus Cereus
Saccharomyces Cerevisiae
Fine Pellicle Sediment
Flocculent
“Flaky”

30. Identify the type of Media
in each tube?
1) Broth
2) Slant
3) Deep
Based on the results of this four way isolation
streak, what do you think this student may
have done incorrectly during his or her four
way streak procedure?
They either did not sterilize the loop between
each quadrant or they reapplied the bacteria
after each Quadrant streak
Observe this Circled colony on this agar
plate. Using this provided diagram as a
guide. Determine the following
characteristics?
Size: 5mm
Margin: Entire
Pigmentation: Cream Color
Elevation: Convex
Form: Circular
Observe this Circled colony
on this agar What type of
Growth pattern is shown in
this test Tube
Fine with a little bit of
sediment at the bottom

31. Week 4
Effects of Temperature on Microbial Growth
Oxygen Requirements
Growth of Anaerobic Organisms

32. Ex. 10
Effects of
Temperature on
Microbial Growth
4 nutrient Agar Plates
Split into 5
Incubators:
4◦C, 25◦C, 37◦C & 45◦C

33. Results
Serratia
Marcescens
Micrococcus
Luteus
Pseudomonas
Fluorescens
Micrococcus
Luteus
Serratia
Marcescens
Escherichia
Coli
Escherichia
Coli
Bacillus
Stearothermophilus
25◦C 37◦C
55◦C
Pseudomonas
Fluorescens
4◦C

34. Psychrophiles
Cold ~ (-5- 20º); optimal: 10º
Mesophiles
Moderate ~ (20º-45º); optimal: 37º
Thermophiles
Hot ~ (Low 45’s – 80’s)
Hyperthermophiles
HOT!! (80’s & some up to 105º))
Escherichia Coli
Micrococcus Luteus
Serratia Marcescens
Saccharomyces Cerevisiae
Bacillus Stearothermophilus

35. Ex. 11
Oxygen
Requirements
Obtain Melted BHI from
water Bath
While BHI tube is still liquefied add 2 drops of the
appropriate inoculum in (brain Heart infusion)
BHI tube using a sterile Pasteur Pipette; Cap
should be loose (but secure)
Roll BHI tube between palms of your hands to disperse the
bacteria throughout the tube, taking care not to create
bubbles or aerate the agar
Place BHI tube in ice bath until solidify 37ºC incubator

36. Results
Bacillus
Subtilis
Obligate Aerobe
Crinkle at top
(Bacteria
Wants O2)
Saccharomyces
Cerevisiae
Microaerophile
Toward
the Top
Concaved
Specks
toward the
Bottom
Clostridium
Sporogenes
Obligate Anaerobe
Serratia
Marcescens
Film at top
Specks
Throughout
the medium

37. Staphylococcus
Xylosus
Enterococcus
Faecalis
Aerotolerant
Micrococcus
Luteus
Obligate
Aerobe
Mycobacterium
Smegmatis
Obligate Aerobe
Toward the Top NO
speck Within the Media
Film at top
Specks
throughout
the medium
When held to light
Speck throughout
Medium No film on
top (Evenly
Distributed)

38. High O2
Low O2
Obligate
Aerobe
Obligate
Anaerobe
Microaerophil
Aerotolerant

39. Obligate (Strict)
Aerobes
Requires O2
 Undergo Aerobic Respiration
 Oxygen finalElectron Acceptor
Microaerophil Require lower O2 levels (2-10%)
 Undergo Aerobic Respiration
 Limited abilityto detoxifyhydrogen peroxide and superoxideRadicals
Facultative
(Facultative
Anaerobes)
Can Live either Presence OR absence of O2 (Prefer Oxygen)
 Aerobic Respiration
 Anaerobic Respiration
 Fermentation
Aerotolerant Can live in either Presence or Absence of Oxygen (Doesn’t Prefer Oxygen)
 Never use Aerobic metabolism
 Have enzymes that neutralizetoxicoxygen
Obligate (Strict)
Anaerobes
O2 is Deadly
 Use anaerobic Metabolism
 Lack Enzymes to neutralizetoxicoxygen
Oxygen Requirements

40. Ex. 12
Growth of Anaerobic
Organisms
Gaspak Jar
The Hydrogen gas combines with free oxygen in the chamber to produce
water. The Reaction is Catalyzed by palladium which is attach to the
underside lid of the Jar . The carbon dioxide replaces the removed
oxygen creating a completely anaerobic environment
2H2 + O2  2H2O
Pseudomonas Aeruginosa
Bacillus Subtilis
Escherichia Coli
Clostridium Sporogenes
Envelope:
Sodium Borohydride  H2 (Hydrogen Gas)
Sodium Bicarbonate  CO2 (Carbon Dioxide)

41. Results
Candle Jar
Growth Should Occur Under Anaerobic Conditions:
Facultative Escherichia Coli
Obligate Anaerobe Clostridium Sporogenes
Clostridium Sporogenes “Obligate Anaerobe”
Escherichia Coli “Facultative”

42. Results
37ºC incubator
Notice Growth Did NOT occur for Obligate
Anaerobe Clostridium Sporogenes
Escherichia Coli Can’t Grow

43. Ex. 12
Growth of Anaerobic
Organisms
4 Thioglycollate Broth Tubes
Pseudomonas Aeruginosa
Bacillus Subtilis
Escherichia Coli
Clostridium Sporogenes
Pink = Oxygen
Yellow = No Oxygen
Resazurin The oxygen concentration at a given level is
indicated by a redox sensitive dye that turns pink in the presence of
oxygen
Sodium Thioglycollate Consumes Oxygen

44. Results
Pseudomonas
Aeruginosa
Obligate
Aerobe
Bacillus
Subtilis
Obligate
Aerobe
(Gravity Pulls Down
Dead Bacteria)
Escherichia
Coli
Clostridium
Sporogenes
Obligate
Anaerobe
Toward
the Top
Bacteria
on Top
Dead
Bacteria
Throughout
(But Prefer O2)
Toward the
Bottom

45. Identify the Oxygen Class & any Example
Genus +Species
1) Aerotolerant Enterococcus Faecalis
2) Obligate Aerobe Bacillus Subtilis
3) Microaerophil Saccharomyces Cerevisiae
4) Facultative Escherichia Coli
5) Obligate Anaerobe Clostridium Sporogenes
Indicate Temperature Class Name the Chemical that is the
reducing agent in the Media?
Sodium Thioglycollate
Name the chemical in this media
that changes color depending on
whether or not oxygen is present
Resazurin
Oxygen Class Tube A Facultative
Oxygen Class Tube B Aerotolerant
Observe this Circled colony Name 2
chemicals in Gas Pak Envelope
1) Sodium Bicarbonate
2) Sodium Borohydride
2 chemicals Produced when chemicals in
Envelope are Activated
CO2 & O2
Write Equation that occurs in GASPAK
Jar that removes O2 and makes chamber
Anaerobic
2H2 + O2 2H2O (Pallidium Catalyst)
4◦C 25◦C 37◦C 55◦C Temperature Class
A - + - - Mesophile
B + + - - Psychrotroph
C - - - + Thermophile
D - + + - Mesophile
E + - - - Psychrophile

46. Week 5
Selective & Differential media
Chemical control of Microorganisms
Chemotherapeutic agents
Additive & synergistic effects on Antibiotics

47. Ex. 13: Use of
Selective, Differential &
Enriched Media
Mannitol Salt Agar
Selective: 7.5% NaCl
Halotolerants
Differential: Carbohydrate Substrate Mannitol &
“phenol Red” (Ability to ferment mannitol)
Red Yellow
fermentation
No fermentation
Staphylococcus xylosus
Enterococcus faecalis
Staphylococcus epidermidis

48. Blood Agar
Differential ONLY: Hemolysis  some bacteria produce exotoxins that cause lysis of RBC
Beta (Burst): Complete Clearing of Blood around colonies
Alpha (almost): Partial lysis Greenish-Yellow Discoloration
Gamma: No lysis
Streptococcus mutans
GammaAlphaBeta
Enterococcus faecalis
Staphylococcus Xylosus
Streptococcus Zooepidmicus

49. Columbia
C-NA agar
Selective: Colistin + Nalidixic Acid
Gram Positive
Differential: Blood agar
Beta, Alpha, Gamma
Alpha
Enterococcus Faecalis
Staphylococcus xylosus
Beta

50. MacConkey
Agar
 Selective: Crystal Violet & Bile Salts
Gram Negative
 Differential: Substrate Lactose & pH
indicator “Neutral Red”
RED  Pink
Escherichia Coli
Enterobacter aerogenes
Morganella Morganii

51. Eosin Methylene Blue Agar
 Selective: Eosin + Methylene Blue
Gram Negative
 Differential: Substrate Lactose
Pink Small amount of acid
Greenish Large amount of acid
Escherichia Coli
Enterobacter aerogenes
Morganella Morganii

52. Ex. 14:
Chemical Control of
Microorganisms
Measuring Zone of Inhibition
Bleach
Lab Cleanerisopropanol
Vinegar

53. Ex. 15:
Chemotherapeutic
Agents
E test
Antibiotic: Trimethoprim & sulfa TS
MIC  .047
Susceptible
S < R >
Ampicillin (AM) 8 8
Daptomycin (DPC) 1 1
Imipenem (IP) 2 8
Tetracycline (TC) 1 2
Trigecycline (TGC) 1 2
Trimethoprim & Sulfa
(TS)
2 4

54. antibiotic Inhibition zone
diameter
Susceptible/
intermediate/
resistant
Nalidixic acid
(NA30)
11mm Resistant
Trimethoprim/Sulfam
ethoxazole (SXT25)
36mm Susceptible
Gentamycin (CN10) 26mm Susceptible
Vancomycin (VA30) 17mm Susceptible
Penicillin (P10) 54mm Susceptible
Cefoxitin (FOX30) 25mm Susceptible
Tetracycline (TE30) 36mm Susceptible
Azithromycin
(AZM15)
25mm Susceptible
Disk diffusion assay

55. Disc Code Resistant
(<mm)
Intermediate
(mm range)
Susceptible
(>mm)
AZM15 13 14-17 18
CN10 12 13-14 15
VA30
Enterococcus
14 15-16 17
VA30
Other
9 10-11 12
P10
Staphylococcus
28 - 29
P10
Enterococcus
14 - 15
P10
Streptococcus
19 20-27 28
P10
Other
19 - 20
TE30 14 15-18 19
FOX30 14 15-17 18
SXT25 10 11-15 16
NA30 13 14-18 19

56. Ex. 16: Additive & Synergistic Effects on Antibiotics
Synergistic
Additive
“Overall no
greater than the
sum of individual
antibiotic.
Uniform”
“Overall effect of
antibiotic combination is
greater than sum of
individual antibiotic.
Merge in the middle”

57. Station 3: MSA plates
1) What does the MSA select for? Halotolerants
2) What are the selective ingredients of MSA? 7.5% sodium chloride
3) What is the carbohydrate in MSA? Mannitol
4) Does the bacteria growing in sector A ferment mannitol? YES
5) Does the bacteria growing on sector B ferment mannitol? NO
6) Give example of a bacterium that ferments mannitol and one that does not ferment mannitol
a. Enterococcus Faecalis
b. Staphylococcus Epidermis
Station 1: EMB and MacConkey Plate
1) What does EMB and MacConkey Plates Select for? Gram –
2) What carbohydrates is in both EMB and MacConkey agar? Lactose
3) What are the selective ingredients in EMB agar? Eosin & Methylene Blue
4) What are the selective ingredients in MacConkey agar?
Crystal Violet & Bile salts
1) What is the pH indicator in MacConkey agar? Neutral Red
2) Does the bacteria growing on sector A ferment Lactose?
EMB (No) & MacConkey (No)
1) Does the bacteria growing on sector B ferment Lactose?
EMB (Yes) & MacConkey Yes
1) Give an example of a bacteria that ferments lactose
and one that does not ferment lactose
a. Escherichia Coli
b. Morganella Morganii

58. Station 3: Mueller-Hinton Plates
1) Measure the zone of Inhibition SXT25 on the disk fusion plate? 23mm
2) Based on your measurement, is the bacteria on this plate susceptible,
resistant or intermediate to this antibiotic. Susceptible
3) Measure the MIC at .032 on the E-test plate. .032
Station 4: CCNA plate
1) What does CCNA select for? Gram -
2) Name the two antibiotics that make CCNA agar selective Colistin & Nalidixic Acid
3) Identify the hemolysis pattern of the bacteria growing on sector A “alpha”
4) Identify the hemolysis pattern of the bacteria growing on sector B “Beta”
5) Give an example of (a) bacterium that is alpha hemolytic (b) Beta Hemolytic (c)
Gamma hemolytic
a. Enterococcus Faecalis (alpha)
b. Staphylococcus xylosus (Beta)
c. Streptococcus Mutans

59. Week 6
Normal microbiota of the mouth
Normal microbiota of the throat & Skin
Cultivation of Urine Specimen

60. Ex. 17: Microbiota of the Mouth
Unbrushed teeth is an accumulation of a biofilm
Cariogenic- Ability to cause dental Carries
*lactobacillus acidophilus, streptococcus mutans (S. Gordonii, S.
salivarius) & actinomyces odontolyticus
Ferment carbohydrates  Lactic Acid
Lowering the pH at the surface of the Enamel which can
decalcify the enamel & lead to cavities
S. Mutans produce enzyme Dextransucrase which
polymerizes sucrose to form a polysaccharide called Glucan
L. Acidophilus produces similar polymer Lexan
Glucan & Lexan are both Glycocalyces

61. Snyder Test
Determine a Persons Susceptibility to dental caries
based on acid production that is assumed to be a result of the
growth of lactobacilli
Ingredients Select: 2% glucose & pH of 4.8
Low pH inhibits growth of most organisms but is ideal for lactobacilli
Indicator Differential: Bromcresol Green (4.84.4)
* Green  Yellow
Green = Slight
Yellow = High
Slight mild Moderate High
Fermenting to Yellow

62. Ex. 18: Microbiota of the Throat & Skin
Blood Agar
Differentiate: Streptococcus
S. Pyogens  Beta Hemolysis (Burst)
S. mutans, S. gordanii, S. salivarius  Alpha Hemolysis (almost)
Chocolate Blood Agar
NOT selective
“lysed Boiled Red blood Cells”
Allows growth of Neisseria & Moraxella
Oxidase Reagent Detects (Cytochrome C)  Turn Purple 30s
Common in young Adults as normal microbiota
Neisseria &
Moraxella
Oxidase Reagent Detects
(Cytochrome C)
Streptococcus
Pyogens
Beta
S. mutans
S. gordanii
S. salivarius
Alpha

63. MSA Plate
Select: Staphylococcus/ Halotolerant “7.5% NaCl”
Differentiate: Mannitol Ferment “pH indicator Phenol Red”
Staphylococcus Epidermidis (drier)  Does not Ferment
Staphylococcus Aureus (moist)  Ferments
M-H Tellurite Plate
Select: Corynebacterium Diptheroids
Present produce gray/Black colonies
Tellurite in the media is reduced intracellularly  Tellurium (grey precipitate)
“Back of ear”“arm… used 0.85% saline swab”
Corynebacterium
Diptheroids
Staphylococcus
Aureus
Staphylococcus
Epidermidis

64. Environmental
Organisms
Sabouraud agar
Fungi (yeast or Mold)
Selects: Acidophiles (acidic Medium pH5.5)
Nutrient Agar Plate
Not Selective or Differential  Acidophils will not grow
Acidophil grows
(Fungi)

65. UTI’s
Urethritis: Infection of the Urethra
Cystitis: Infection of the urinary bladder
Pyelonephritis: Infection involving kidneys
* Caused by … E. Coli, Staphylococcus Aureus,
Enterococcus Faecalis, Proteus mirabilis & P. Vulgaris
Micturition in to a Cup  Midstream *adequate cleaning
of the genitals
HardyCHROM is a Non-selective/ differential
Ingredients: Peptones, Proprietary blend of chromogenic
substrates & indicators that cause different organisms to
produce different colored colonies
# 𝒐𝒇 𝒄𝒐𝒍𝒐𝒏𝒊𝒆𝒔
𝟎.𝟎𝟏𝒎𝒍
=
𝑪𝑭𝑼
𝒎𝒍
Critical threshold = 1*105 bacteria per ml of urine
Early phase of UTI = 1*102 to 1*104
Ex. 19:Cultivation of Urine Specimen

66. Klebsiella
Dark Blue/Indigo
Cirobacter
Dark Blue With pink Halo
E. Coli
Rose/Magenta
Protease Vulgaris
Blue/Green with Orange Halo
Pseudomonas
Colorless
Enterococcus Faecalis
Teal/Turquoise

67. Station 2: Skin Microbiota
1) What genus of the skin microbiota does the MSA select for? Staphylococcus
2) What species of the skin microbiota is growing on sector A? Aureus
3) What species of the skin microbiota is growing on sector B? Epidermidis
4) Give the common name & genus of the bacteria growing on the MHT plate Diphtheria
colonies, Corynebacterium
5) What is the name of the metal in this plate that selects for the bacteria on MHT? Tellurite
Station 1: Microbiota of the Mouth
1) What is the name of the agar we use to test for susceptibility to dental caries? Snyder deep agar
2) What genus of bacteria does this agar test for? Lactobacillus, Streptococcus & acintomyces
3) What makes this agar selective? The pH from 2% glucose
4) What carbohydrate is in this agar? Glucose
5) What is the name of the ph indicator in this agar? Bromersol Green
6) what causes the color of the agar to change from green to yellow? Color change is caused by acid
production
Station 3: Throat Microbiota
1) Name the species of throat microbiota that is growing on this blood plate? Pyogenes (Beta Hemolytic)
2) What is the main ingredient in chocolate agar? Lysed boiled red blood cells
3) What genus of throat microbiota doe we culture on chocolate agar? Neisseria & Moraxella
4) What reagent has to be added to the growth on the plate to detect this genus? Oxidase Reagent

68. Station 4: Urine Cultures
1) Name the pathogen growing on sector A of the HardyCHROM plate? Escherichia Coli
2) Name the pathogen growing on Sector B of the HardyCHROM plate? Cirobacter
3) 0.01ml of a urine specimen is streaked onto a nutrient agar plate, and after incubating the plate
overnight at 3 7 degrees C. 263 colonies are present on the plate. Calculate how many bacteria
were in the patients urine sample. Does the value mean that the patient has a UTI?
263
.01
= 26,300  2.63 * 104 NO UTI less than 105
Snyder: Selective & Differential
MSA: Selective & Differential
MHT: Selective
Blood: Differential
Chocolate: Differential
Sabouraud: Selective
Nutrient: Neither
E. Coli
Rose/Magenta
Cirobacter
Dark Blue With pink Halo