MICROBIOLOGY FINAL LABARATORY EXAM QUESTIONS AND THEIR ANSWERS

MICROBIOLOGY FINAL
LABARATORY EXAM QUESTIONS
AND THEIR ANSWERS
What is the difference between selective and differential
media?
Selective media allows only certain bacteria to grow on the
plate and differential media allows you to visualize differences
between bacteria based on differences in growth patterns or
colonial morphology
What was the colonial appearance of Enterobacter aerogenes
on the EMB plate?
clear with a pigmented center
Did Shigella flexneri grow on the SS agar?
yes
What was the colonial appearance of Escherichia coli grown
on the SS agar?
pink
TSI Results: Escherichia coli-gas production?
positive
Did Escherichia coli grow on the MacConkey's agar?
yes

,What was the colonial appearance of the Escherichia coli on
the MacConkey's agar?
pink/red
SIMS media: is Escherichia coli motile?
yes
What inhibits the growth of gram positive organisms on SS
media?
bile salts and sodium citrate
Indicate if the following media is selective, differential or both.
MSA agar
both selective and differential
TSI Results: Shigella flexneri-H2S production?
negative
SIMS media: Escherichia coli-H2S production?
negative
TSI Results: Shigella flexneri
alkaline/acid
What inhibits the growth of gram positive organisms on
MacConkey's media?
crystal violet and bile salts

, What was the colonial appearance of Escherichia coli on the
EMB plate?
green sheen
TSI Results: Salmonella enteritidis-sugar fermented?
glucose
SIMS medis: Shigella flexneri-indole production?
negative
Did Escherichia coli grow on the SS agar?
yes
TSI Results: Shigella flexneri- sugar fermented?
glucose
What was the colonial appearance of Shigella flexneri on the
SS agar?
clear/non-pigmented
What inhibits the growth of gram positive organisms on MSA
media?
7.5% NaCl
SIMS media: Escherichia coli- indole production?
positive
TSI Results: Salmonella enteritidis
alkaline/acid