Lab Flashcards
Phenol Red Broth
(+) Yellow broth, bubble in tubeA/G
(+) Yellow broth, no bubbleA/–
(-) Red broth, no bubble* –/–
(-) Pink broth, no bubble *K
Methyl Red & Voges-Proskauer
Red *(+)
No Color Change *(–)
Catalase Test
Bubbles *(+)
No Bubbles *(–)
Oxidase Test
Dark Blue/Purple within 20/s*(+)
No color change to Blue/Purple within 20/s *(–)
Nitrate Reduction Test
- Gas (non-ferm) *(+)
- Gas (ferm, or status unknown)
- Red color (after Reagents A&B) *(+)
- No color change(after Reagents A&B)
- No color change(after zinc dust) *(+)
- Red color(after zinc) *(–)
Citrate Utilization Test
Blue(even small amount) *(+)
No color change; growth *(+)
No color change; no growth *(–)
Malonate Utilization Test
Dark Blue *(+)
No color change; or slightly yellow *(–)
Decarboxylation Test (Ornithine)
Purple ( may be slight) *(+)
No color change *(–)
Yellow *(–)
Phenylalamine Deaminase Test
Green color *(+)
No color change *(–)
Starch Hydrolysis (Amylase Test)
Clearing around growth *(+)
No clearing around growth*(–)
Gelatin Hydrolysis
Gelatin is liquid (control is solid) *(+)
Gelatin is solid *(–)
Urea Hydrolysis
24 hours: 1.All pink *(+) 2.Partially pink *(w+) 3.Orange or yellow *(w+) 4.Orange or yellow*(--) 24h to 6d: 1.Gelatinase is present *(+) 2.All pink or Partially pink *(w+) 3.All pink or partially pink *(w+) 4.Orange or yellow*(--)
Indole Production
Layer on top of media turns Red/Pink *(+)
Reagent color is unchanged *(–)
Kliger Iron Agar (KIA)
- Yellow slant/yellow butt *(A/A)
- Red slant/yellow butt
* (K/A) - Red slant/red butt
* (K/K) - Red slant/ no change in butt
* (K/NC) - No change in slant/no change in butt *(NC/NC)
- Black precipitate in agar *(H2S)
- Cracks in or lifting of agar
Litmus Milk Medium
1.Pink color *(A)
2.Pink and solid (white in the lower portion if litmus is reduced) clot not movable *(AC)
3.Fissures in clot *(G)
4.Clot broken apart *(S)
5.White color (lower part of medium) *(R)
6.Semisolid and not pink;
clear to grey fluid on top *(C)
7.Clarification of medium; loss of body *(D)
8.Blue medium or blue band on top *(K)
9.No change *(NC)
Enterotube II Interpretation
- Add the circled numbers for each groups up and write the sum on the corresponding lines
(e. g. if the enterotube showed a + reaction for glucose and gas then you write a number 2 + 1 = “3” on the first line) - The established ID code identifies the bacterium under investigation with the help of the Coding Manual
Why use Enterotube?
The Enterotube is an example of a rapid, multi test system used in identification of unknown oxidase- negative, gram- negative, rod shaped bacteria of the family Enterobacteriaceae.
Flagella:
Structure that allows bacteria to move
Motility test and its media:
Semisolid media that contains TTC and less agar to make it more gelatinous. TTC is salt that becomes oxidized when exposed to air.
Aerobic/ Anaerobic/ Facultative
Aerobic: require oxygen
Anaerobic: do not require oxygen
Facultative: can grow in both environments but prefer oxygen.
GasPak/ Anaerobic chamber
made of metal and will work as a catalyst. Takes O2 that is floating and takes O2 Hydrogen to catalyze them by making them water.
Spectrophotometry
An apparatus for measuring intensity of light in a part of the spectrum, as transmitted or emitted by particular substances.
What is the plate count method?
The plate count method means diluting bacteria with a diluent solution (e.g. sterile saline) until the bacteria are dilute enough to count accurately when spread on a plate. The assumption is that each viable bacterial cell will develop into a single colony.
Absorbance method:
The reason why we use it
Purpose
Advantages/disadvantages
Measure the rate of growth of bacterial culture.
Plate count method:
The reason why we use it
Purpose
Advantages/disadvantages
Calculate the number of bacterial cell per each ml of culture “concentration”
Effect of temperature on microbial growth
Each species is characterized by a min, max and optimum temp.
Effect of UV light on microbial growth
UV travels in waves and its distinguished by wavelengths. The effect of UV light is related to time of exposure, lamp intensity, and distance from the target.
Concept of thermal death time and the effect of UV light on bacterial DNA.
Wavelengths from 100nm to 280nm of bacterial exposure for more than a few minutes results in irreparable DNA damage and death of the organism.
Kirby-Bauer Method
antimicrobic-impregnated paper disks show the zone of inhibition around the disk.
Antibiotics
natural antimicrobial agents produced by microorganisms
Antimicrobials
synthetic agents that are used to treat bacterial infections
Bactericidal
drugs that kill an organism
Bacteriostatic
stop the bacteria from dividing but do not kill them
Isolation of Staphylococcus
-Mannitol Salt Agar
-Selective
-Results:
(–) no growth/ poor growth: Not staph
(+) Good Growth: Staph
(+) Yellow halo: Staph aerous
(+) Red growth/ no halo: Staph other than S. aureous
Isolation of Streptococcus
-Blood Agar
-Differential
-Results:
(+) clearing around growth: Hemolyzed B
(+) Green around growth: Hemolysed x
(–) No change: no hemo
Analysis of food and water
#1 Presumptive test : Lactose Ferm--> negative=STOP
--> positive= #2
#2 Confirmation test: MAC plate -->
negative= no growth/no green=STOP
positive= green / go to #3
#3 Completed test: any biological test that test positive for E.coliHemagglutination
clumping of RBC to a specific antigen
Antibodies
Antigens
Agglutination
Antibodies: molecules that are small and soluble
Antigen: binds to antibody
Agglutination: when antibodies bind to an antigen (clumping/ cluster)
Immunoprecipitation
is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein.
How to determine blood type and how to determine correct donor/recipient matches.
You can work that out by mixing the patient’s blood with three different reagents containing either of the three antibodies: A, B or Rh.
