Medical Bacteriology Lab Exam 2 with
complete solutions
The ONPG test determines the ability for the organism to utilize what sugar? - correct answer
✔✔Lactose
Once acidified, the phenol red indicator in many different medias convert to what color? - correct
answer ✔✔yellow
True or False: Chocolate agar has cocoa powder in it to enhance fastidious organism growth - correct
answer ✔✔False
What is the gram stain and morphology of Neisseria/Moraxella catarrhalis under the microscope? -
correct answer ✔✔gram-negative diplococci
Given the options, which plate should you obtain acolony from when performing the oxidase test?◦ A.
MacConkey◦ B. Nutrient agar - correct answer ✔✔B. nutrient agar
M. catarrhalis was previously placed in a separate genus named what? - correct answer ✔✔Branhamella
What was used to justify inclusion of the species M.catarrhalis in the genus Moraxella? - correct answer
✔✔DNA hybridization studies and 16S rRNAsequence comparisons
Which Neisseria app. is fastidious? - correct answer ✔✔N. gonorrhoeae
What agar is best used to grow N. gonorrhoeae? - correct answer ✔✔Chocolate and MTM agar
In what conditions does N. gonorrheae grow under? How is this achieved in a laboratory setting? -
correct answer ✔✔CO2 and candle jars
, What kind of pathogen is Morexella catarrhalis? - correct answer ✔✔opportunistic
What are two common infections caused by M. catarrhalis? - correct answer ✔✔Otitis media (ear
infection) and upper respiratory infection
How is the shape of M. catarrhalis described? - correct answer ✔✔short gram-negative bacilli
"Picky bugs love chocolate" - correct answer ✔✔fastidious organisms
How is chocolate agar different from blood agar? - correct answer ✔✔Blood cells are cooked/lysed and
have more moisture
Why is chocolate agar used to isolate N. gonorrhoeae, N.meningitidis, Haemophilus influenza? - correct
answer ✔✔These bacteria lack haemolysin and are unable to breakapart the red blood cells and obtain
iron to surviv
What is Modified Thayer-Martin is selective for? - correct answer ✔✔Neisseria spp.
What are the four antibiotics used in MTM agar? And what do they inhibit? - correct answer
✔✔vancomycin: gram positives
colistin: other gram negs
nystatin: yeasts
trimethoprim: Proteus
True or False: All Neisseria's are oxidase positive - correct answer ✔✔True
On a bacticard what does it mean if the IB circle is blue/green? - correct answer ✔✔M. catarrhalis
Bacticard= BGAL circle is blue/green? - correct answer ✔✔N. lactamica
complete solutions
The ONPG test determines the ability for the organism to utilize what sugar? - correct answer
✔✔Lactose
Once acidified, the phenol red indicator in many different medias convert to what color? - correct
answer ✔✔yellow
True or False: Chocolate agar has cocoa powder in it to enhance fastidious organism growth - correct
answer ✔✔False
What is the gram stain and morphology of Neisseria/Moraxella catarrhalis under the microscope? -
correct answer ✔✔gram-negative diplococci
Given the options, which plate should you obtain acolony from when performing the oxidase test?◦ A.
MacConkey◦ B. Nutrient agar - correct answer ✔✔B. nutrient agar
M. catarrhalis was previously placed in a separate genus named what? - correct answer ✔✔Branhamella
What was used to justify inclusion of the species M.catarrhalis in the genus Moraxella? - correct answer
✔✔DNA hybridization studies and 16S rRNAsequence comparisons
Which Neisseria app. is fastidious? - correct answer ✔✔N. gonorrhoeae
What agar is best used to grow N. gonorrhoeae? - correct answer ✔✔Chocolate and MTM agar
In what conditions does N. gonorrheae grow under? How is this achieved in a laboratory setting? -
correct answer ✔✔CO2 and candle jars
, What kind of pathogen is Morexella catarrhalis? - correct answer ✔✔opportunistic
What are two common infections caused by M. catarrhalis? - correct answer ✔✔Otitis media (ear
infection) and upper respiratory infection
How is the shape of M. catarrhalis described? - correct answer ✔✔short gram-negative bacilli
"Picky bugs love chocolate" - correct answer ✔✔fastidious organisms
How is chocolate agar different from blood agar? - correct answer ✔✔Blood cells are cooked/lysed and
have more moisture
Why is chocolate agar used to isolate N. gonorrhoeae, N.meningitidis, Haemophilus influenza? - correct
answer ✔✔These bacteria lack haemolysin and are unable to breakapart the red blood cells and obtain
iron to surviv
What is Modified Thayer-Martin is selective for? - correct answer ✔✔Neisseria spp.
What are the four antibiotics used in MTM agar? And what do they inhibit? - correct answer
✔✔vancomycin: gram positives
colistin: other gram negs
nystatin: yeasts
trimethoprim: Proteus
True or False: All Neisseria's are oxidase positive - correct answer ✔✔True
On a bacticard what does it mean if the IB circle is blue/green? - correct answer ✔✔M. catarrhalis
Bacticard= BGAL circle is blue/green? - correct answer ✔✔N. lactamica
