Lab Practical 1 Flashcards
Serratia marcescens gram pos or neg
negative
Endospore stain method
Cover slide with paper towel and saturate with malachite green
Steam for 5 minutes
Rinse
Safranin
Rinse
Blot
spirit blue test/lipase, which pos and neg?
s. aureus
e.coli
s. aureus positive
e. coli negative
What were the two organisms tested in the catalase test and what was the result for each?
s. aureus- catalase positive
l. lactis- negative
From the carbohydrate metabolism lab which organism could be classified as a non fermenter?
pseudomonis aeroginosa
What does the citrate test, test for?
Differentiate between members of Enterobacteriaceae.
The ability to use citrate as a carbon source and perform citrate fermentation. Contain citrate permease.
What bacterial cell structure does the Gram reaction test?
peptidoglycan layer in cell wall
gram stain method
Crystal Violet
rinse
Iodine
rinse
Alcohol
Rinse
Safranin
Rinse
Blot
decarboxylase test, which pos and neg?
p. merabilis
e.coli
e. coli postive
p. merabilis negative
Staphylococcus aureus gram pos or neg?
positive
geletin hydrolysis test, which pos and neg?
b.cereus
e.coli
b. cereus positive
e. coli negative
m. phlei acid fast pos or neg?
postive
why did e. coli have a green sheen in the EMB?
ferments lactose with acid production
starch hydrolysis test, which pos and neg?
b.cereus
e.coli
b. cereus positive
e. coli negative
For the decarboxylase test: describe the general reaction of this test, what does a positive result look like and why does the indicator dye bromocresol purple change color with a positive result? What was added to the top of the tube and why?
Testing for the ability to turn on the decarboxylase gene. A positive result is purple and changes due to the high pH due to a build up of amines. Mineral oil is added to block oxygen and induce fermentation.
What is EMB agar?
selective agar for gram negative coliforms
acid fast stain method
carbolfuschin stain
rinse
acid-alcohol
rinse
methylene blue
rinse
blot
Heat or chemical mordant
For MR test which bacteria had a positive result and what did it look like? What did it mean?
E. coli and bright red. Mixed acid producer.
Which organisms are endospore formers?
bacillus subtilis and bacillus cereus
s. aureus, acid fast pos or neg?
negative
Explain how the gelatin test works and what is meant by a positive result.
Bateria with gelitanase introduced to gelatin will liquify gelatin.
Bacillus cereus gram pos or neg?
positive
For the indole production portion of the SIM test, which bacterias had a positive result and what did it look like?
K. oxytoca
E. coli
P. valgaris
pink layer on top when kovac’s reagent added
What are the expected oxygen requirements for catalase-positive and catalase-negative species?
Positive: aerobic or facultative aerobe
Negative: anaerobe
What does the acid fast stain work on?
mycolic acid in the waxy cell wall
For the VP test, which bacteria had a positive result and what did it look like?
e. aerogenes, pinkish/red, fermentation with aceiton
What are the arrangments for bacteria? 6
diplo- two cells
staphylo-cluster of cells
strepto-chain of cells
tetrad- four cells
sarcina- eight cells
plaisades- group of rods
What is the positive and negative result for spirit blue? What is it testing?
Testing for the production of lipase
Positive: halo around growth
Negative: no halo
For the sulfur production portion of the SIM test, which bacteria had a positive result and what did it look like?
P. valgaris, mostly black, H2S produced
What does a change from red to yellow mean in the phenol red test? Why is it changing?
fermentation is occuring. Changes to yellow because acid is produced.
Escherichia coli gram pos or neg?
negative
What enzyme does an organism have if it is starch positive?
amylase
Explain how the starch hydrolysis test is prepared and what do we add to read the test and why?
Use Starch agar and add iodine to allow us to view the halo around the colony.
What is a positive and negative citrate test? At what pH does the color change happen?
Positive: blue
Negative: green
Turns blue at 7.6 (basic)
Cell morphologies 7
coccus- ball
bacillus- rod
vibrio- curved rod
spirillum- cork screw
spirochete- wavy
coccobacillus- short rod
pleomorphic- multiple shapes
