Lab 2 Flashcards
Petroff-hauser chamber is used for which counting technique?
What type of medium is mostly done with this?
Direct Count
Milk
3 types of direct count
Direct microscope
Most probable number
Standard Plate Count
Drinking water safety is determined by this type of cell count?
What bacteria is the indicator
MPN
Coliforms
Coliforms found in the intestine of warm-blooded animals ferments _____ to produce acid and gas
Lactose
Where is 1 ml on the pipette machine
0
Between any two numbers on the pipette machine is how much volume of liquid?
.1ml
Test tube B has a dilution of 10,000 what is the plate dilution rate of
1ml
.1ml
10,000
100,000
Test tube C has a dilution of 1,000,000 what will the plate dilution be from
1ml
.1ml
1,000,000
10,000,000
Test tube A (10ml) 1:100 dilution
.1ml is added to testtube B (9.9ml)
What is B’s dilution?
1:10,000
Test tube B (10ml) at 1:10,000 dilution
.1ml is added to
Testtube C (9.9ml)
What is the total dilution?
1,000,000
Name of machine used in class with the electrode that counts the cells
Quebec colony counter
Dilutions from 4 plates used in the Standard Plate Count
1:10,000
1:100,000
1:1,000,000
1:10,000,000
The bacteria we looked at which was a Mesophile.
Grows in Temps between 25 - 45 C
Serratia marcescens & Escherichia coli & B cereus
Optimum temp 37c
This bacteria grew best at .5% NaCl
Escherichia coli
Which bacteria grew best at a salt range between 5% - 10%
S. epidermidis
E coli has which kind of oxygen requirements
Facultative anaerobe
Pseudomonas aeruginosa has which kind of oxygen requirements
Obligate aerobe
Staphylococcus epidermidis has which kind of oxygen requirements
Faculative anaerobe
What is the purpose of thioglycolate?
To make different oxygen requirements in a broth
Which test did we use the needle to inoculate
Do determine oxygen requirements with thioglycolate tubes
E. Coli best level of salt
This is a good card
.5%
S. Epidermidis grows best at which salt range
7.5 - 10%
Bacillus cereus, E. Coli, and Staphylococcus epidermidis all have this oxygen requirement
Facultative Anaerobe
Pseudomonas aeruginosa has this oxygen requirement?
Obligate aerobic
Temp range
-5 - 15 c
Psychrophile
Temp range
15 - 30 fridge temps
Psychrotroph
Temp range
25 - 45 c Human body temperature
Mesophile
Temp range
45 - 70 c
Thermophile
Temp range
70 c +
Hyperthermophile
Oxygen requirements
Require oxygen
Which species did we look at like this
Obligate aerobe
Pseudomonas aeruginosa
Oxygen requirements
Will die in presence of oxygen
Which species did we look at like this
Anaerobic
None
Oxygen requirements
Does not require oxygen but does best with it
Which species did we look at like this
Facultative anaerobe
E. coli, B. cereus, S. epidermidis
Oxygen requirements
These species require only a small amount of oxygen
Which species did we look at like this
Microaerophile
None
After several days what happens to halobacterium in a 35 % salt
It turns red
What is the red pigment halobacterium produces
Prodigiosin
The availability of water is called…
And the values are 0 -1 the close to 1 the more…
Water activity
More water is available to the cell for metabolism
These types of organisms grow where sugar concentration is high
Osmophiles
2 common methods to obtain pure cultures
Streak plating & pour plate
How are counts on Standard Plate Count reported as
Colony forming units
What numbers of CFU’s are considered statically viable
30 - 300
What is an example of “indirect method “ of counting cells
Turbidity
Spectroscopy
Oxygen requirements
Growth only just below the surface
Microaerophile
Oxygen requirements
Growth only at the bottom
What did we look at like this
Strict anaerobe
None
Oxygen requirements
Uniform growth throughout the entire tube
Aerotolerent anaerobe
Oxygen requirements
Growth throughout but mostly at the top
What did we look at like this
Facultative anaerobe
B cereus, E coli, S epidermidis
Oxygen requirements
Growth only at the top
What species did we look at like this
Obligate aerobe
Pseudomonas aeruginosa
Advantages of the 2 pure culture techniques
- Streak plate method: less equipment needed and quicker
(This is the one we did in class) - Pour plate method: Is easier to get good results than streak plate which can require practice.
Serial dilution
10-⁴, 10-⁵, 10-⁶
1/10,000
1/100,000
1/1,000,000
Standard Plate count Alt method
From Culture to 3 bottles what is the dilution and amount of liquid transferred?
What is the amount of liquid transferred to 4 plates and dilution
Oringal Bottle to A: 1:100, B 1:10,000 C 1:1,000,000 (1ml) for each transfer
From bottle B 1ml 1:10,000 & .1ml 1:100,000
From bottle C 1ml 1,000,000 & .1ml 1:10,000,000
Thymine dimers are
Pair of abnormally chemically bonded adjacent thymine bases in DNA caused by UV light
Which wave length is moat dangerous to bacteria
260 nm. It is the wave length which DNA maximumly absorbs UV light
Which bacteria (Bacillus megaterium or Staphylococcus epidermidis) is more resistant to uv light and why?
Bacillus megaterium due to endospore formation
How do bacteria repair UV damage
- Photoreactivation
In many procaryotic and eucaryotic cells, photoreactivating enzyme mediates light-dependent repair of UV-induced damage: the enzyme binds to a pyrimidine dimer in DNA, and, on absorption of a photon (300-600 nm), specifically monomerizes the dimer, thus repairing the DNA - Nucleotide excision
- SOS repair
Which of the following are “total counts or viable counts”
MPN
MICROSCOPIC COUNT
STANDARD PLATE COUNT
TURBIDITY
Viable
Total
Viable
Total
How would you get a bacterial culture to a 1:10 dilution/ 1:100
From a Pure solution
On a plate count
1:10 plate .1ml liquid culture
1:100 add 1 ml to liquid culture and plate .1ml
Bacterial cell in the following environment, will it (Solution) be Hyper,Hypo,Isotonic
.5%
5%
10%
15%
Iso
Hyper
Hyper
Hyper
How can an anaerobic condition be made in a jar?
Gaspak system.
Water is added forming hydrogen and Carbon Dioxide.
Palladium a Catalyst, catalyzes the formation of Water
Combining Hydrogen & Oxygen
Removing the Oxygen
In a Wrights tube how are anaerobic conditions created?
On the nutrient agar slant
NaOH oxidizes Pyrogalloland removing Oxygen
How does Oxyrase plate work?
It makes an anaerobic environment for the medium itself
Ingredient in Brewers anaerobic agar that removes oxygen
Thioglycolate’s free sulfhydral group reduces any O² present
Which species turned pink in 25C mesophile range
Serratia Marcescens
Shower slime mold
What are Psychrophile Ranges
-5 -15C
What are Psychrotrophe ranges
15 - 30 Fridge temps
What are mesophile ranges
25 - 45C
What are Thermophile ranges
45 - 70
What are hyperthermophile ranges
70+ C
S. aureus is gram positive and is most harmed by Disinfectants or Antibiotics
Disinfectants
Lysol, 1:10 bleach, Isopropyl alcohol are…
Disinfectants
Hydrogen peroxide, listerine, Betadine, 5% aqueos Iodine
Antiseptics
The least effective antibiotic was
Penicillin
Pseudomonas aeruginosa has this gram status
Negative
Streptomycin broad or narrow spectrum
Broad
Betadine is a type of Antiseptic that contains…
Is it effective
Iodine
Very
Polymyxin is this spectrum of antibiotic
Narrow
Sulphadiazine broad or narrow spectrum
Broad
Is penicillin broad or narrow spectrum
Narrow
- is resistant or sensitive to a drug
+ is resistant or sensitive to a drug
Where did the growth go to
- resistant No Destruction of bacterial growth
+ is sensitive Destruction of bacterial growth
- All the
Human body temperature in C
37
At which temperature did all species experience best growth
38 mesophile range
Which type of bacteria best survive high osmotic pressure
Halophiles Halobacterium salinarium
What does pink mean in a thioglycolate broth
Presence of oxygen
Media used for osmotic pressure
Agar plates with varying concentration of salt
List organsimis in order of resistance to osmotic pressure
Halobacterium salinarium Most
Staphylococcus epidermidis 2nd
E coli Least
List species and results of thioglycolate tubes (4)
E coli, Bacillus cereus, Staphylococcus epidermidis (Facultative anaerobe)
Pseudomonas aeruginosa
Obligate aerobe
Water activity and osmotic pressure
Name 3 species and the results
E coli grew best at .5%
S epidermidis grew best at 5-10%
Halobacterium salinarium grew best at 35%
Medium used for temperature sensitivity
Nutrient broth
Technique and medium used for osmotic pressure
Agar plate / single streak
Temps used for growth, which had the best results
5, 25, 38, 55
38
Salt concentration used for osmotic pressure
. 5
5
10
25
Bacteria used for UV light exposure
Which survived better
B. Megaterium (Better)
S. epidermidis
How many times more resistant was B. megaterium than S. epidermidis
5 times
Method used for UV light exposure
Streak each plate with a swab of bacteria broth twice at 90 degree angles & around the outside. Creates a Bacterial lawn
Times for UV light exposure and which time did they grow in
30 seconds
60 seconds
5 minutes
15 minutes
30 minutes
30sec- 5 mins
Technique used for evaluation of Disinfectants and antiseptics
Filter Paper Disc Method
•3 nutrient agar plates for each culture: Sa, Psa, Ec
•1 plate for control for each culture
•Swab 2 of each nutrient agar plate thoroughly for each culture: Sa, Psa, Ec
•Sterilize tweezer in between each disc with Bunsen burner
•Dip each disc into each solution and place disc in appropriate area on plates
•1 of each swabbed culture plate used for Antseptics: Betadine, Listerine, Hydrogen Peroxide
•1 of each swabbed culture plate used for Disinfectants: 1:10 Bleach, 5% Lysol, Isopropyl Alcohol, 5% aqueous iodine
Organsims used for antiseptics & disinfectants
S. aureus & P. aeruginosa
Media used for Antimicrobic Sensitivity Testing: Kirby Bauer Method
5 Mueller-Hinton (MH) Agar plates
The Zone of inhibition is …
circular area around the spot of the antibiotic in which the bacteria colonies do not grow.
The purpose of this test is to test the sensitivity or resistance of aerobic or facultative anaerobes to various microbial compounds
Kirby-bauer
General Zones of inhibition and their significance
<14 Zone is smaller than 14 Resistant
15-17 intermediate
>18 Zone is bigger than 18 Sensitive
