LAB REPORT 7- Selected
questions from Exercises 5-1 & 5-2 & 5-18 & 5-19 ( aka intracellular
enzymes & multiple-test media)
Bacteria
to be used in exercises regarding the phenol red glucose media and the OF media
include: E. coli, Pseudomonas aeruginosa, Proteus vulgaris
Bacteria
to be used in the exercises regarding the SIM and TSIA media include: E. coli,
Enterobacter aerogenes, S. aureus, Proteus vulgaris, Pseudomonas aeruginosa,
Serratia marcescens (the specific bacteria depend on the media.)
Q1.
All enterics are facultative anaerobes. What
color results would you expect for organisms in O-F glucose media inoculated
with an enteric. Remember to describe both sealed and unsealed tubes. How would an obligate aerobe appear in both
the sealed and unsealed tubes? What
would happen if lactose were used instead of glucose? Would you expect the
results for E. coli and P. vulgaris to be identical? Explain based on your
knowledge from how these two bacteria grow on MacConkey media.
Q2.
List two advantages of a multi-test system such as triple sugar iron agar or
SIM.
N.B. To help you figure out the results of these two
exercises, you should fill out the following tables for your lab report using
the information that you learned in lab.
These tables are not the same format as in class. I want to see that you really understand the
material.
Results: 2 Tables
relating to the
OF media. Remember: the OF assay is done with pairs of tubes so a microorganism is introduced into 2 OF tubes
and one tube receives an overlay of mineral oil!!!)
Table
for 5-1 A. Which microorganism(s) give
the following results for this pair of tubes?
Is
this bacterium oxidative Which
of the used bacteria
Medium + or mineral oil Reaction or
fermentative? show this reaction?
OF tube /without mineral oil Yellow
OF tube/with mineral oil Green
Table
for 5-1 B. Which microorganism(s) give
the following results for this pair of tubes?
Is
this bacterium oxidative Which
of the used bacteria
Medium + or mineral oil Reaction or
fermentative? show this reaction?
OF tube/without mineral oil Yellow
OF tube/with mineral oil Yellow
Results: 3 Tables
relating to the phenol red glucose media
Interpretation
Is sugar fermented? Bacteria used in class with
Medium Reaction i.e. acid/gas/neither? this reaction if any
Phenol red /w glucose Yellow no
air bubble
(or
very small bubble)
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
–
Phenol red/w glucose Yellow with
air bubble
– – –
– – –
– – –
– – –
– – –
– – –
– –
– – –
– – –
– –
Phenol red/w glucose Orange no
air bubble
Table relating to SIM media (adapted from Table 26-6 on page 235 in Wistreich
manual)
Which of the used bacteria
Medium Reaction Interpretation
show this reaction?
Sulfide indole motility a) Blackening
of the medium
(SIM)
–
– –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– –
Medium stays yellow
__________________________________________________________________________
b) Red color formed with addition of
Kovacs reagent
– – –
– – –
– – –
– – –
– –
– – –
– – –
– – –
– – –
– –
The layer containing the Kovacs
Reagent stayed yellowish
___________________________________________________________________________
c) Growth only on line of inoculation
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
–
Growth throughout the
tube
Table relating to TSIA media (substituting Triple Sugar Iron Agar (TSIA) for Kligler Iron Agar which only has
glucose and lactose)
Note: This table is also
adapted from Table appearing in Ex. 26 of Wistreich manual)
Which
bacteria (if any)
Medium Reaction Interpretation show this reaction?
Triple Sugar a) Yellow butt, slant red
Iron Agar –
– – –
– – –
– – –
– – –
– – –
– – – –
– — –
– – –
– –
(TSIA) b)Yellow butt, yellow slant
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
–
c) large holes in the agar
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
–
d)formation of black precipitate
– – –
– – –
– – –
– –
– – –
– – –
– – –
– – –
– – –
– –
e)Red butt, red slant
Note:
For exam i)would be a good idea to understand difference terms, oxidative
organism vs. fermentative organism
ii)know name of the pH indicator used in the media used in Exercise 5-2 and
where you saw it in other media iii)how might the results obtained in these
exercises be used for the identification and/or classification of bacteria. Also
useful: a)With respect to the phenol red glucose media, what is the Durham tube
and what is its purpose? b)What is the purpose of the mineral oil for the OF
media?
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