MLT Microbiology Exam Questions
with Correct Answers
What organism is NOT OXIDASE POSITIVE? - Answer-Yersinia enterocolitica
Which organisms are oxidase positive? - Answer-Aeromonas hydrophilia,
Pseudomonas aeruginosa, Vibrio parahaemolyticus
Rice water stools often contain a pure culture of what organism? - Answer-Vibrio
cholerae
What is the reagent used for the string test? - Answer-0.5% sodium deoxcholate
What allows visibility of acid production by oxidizers in oxidation fermentation (OF)
medium? - Answer-peptone content is low
How many tubes of OF media is (are) inoculated, and under what atomospheric
conditions? - Answer-two tubes, one covered with oil so that air is excluded
Which organism is part of the normal flora of the skin? - Answer-Acintobacter
calcoaceticus
Which organism is oxidase positive? - Answer-Pseudomonas aeruginosa
Which organisms are oxidase negative? - Answer-Gardnerella vaginalis, Acinetobacter
calcoaceticus, Stenotrophomonas maltophilia
What is an acceptible anaerobic specimen? - Answer-body fluid submitted in a syringe
Naegler agar is selective medium for which organism? - Answer-Clostridium
Which Gram-negative anaerobe is resistant to penicillin? - Answer-Bacteroides fragilis
what best describes Propionibacterium? - Answer-anaerobic, Gram-positive bacilli
What Clostridium produces a double zone of hemolysis around colonies on blood agar?
- Answer-C. perfringens
Which Clostridium produces spores that are usually round and terminal? - Answer-C.
ramosum
, Which anaerobic, Gram-positive rod produces terminal "tennis racket" spores? -
Answer-Clostridium tetani
What species of Clostridium causes antimicrobial-associated diarrhea? - Answer-C.
Difficile
Which Gram-negative, anaerobic cocci produces a red fluorescence under ultraviolet
light? - Answer-Veillonella
What best describes Peptococcus? - Answer-anaerobic, Gram-positive cocci
What term describes the morphology of organisms that vary in size and shape? -
Answer-pleomorphic
Capsules are the basis of which test? - Answer-serotyping
A mucoid colony on blood agar medium indicates that which characteristic may be
present? - Answer-organism has a capsule
What are dark staining granules called? - Answer-metachromatic
Which organisms are non motile? - Answer-Shigella and Klebsiella
In the bacterial growth cycle, growth ceases because nutrients are exhausted or toxic
metabolic products have accumulated in what phase? - Answer-stationary phase
What genera of bacteria form spores? - Answer-Bacillus, Clostridium
What term is used to describe bacteria that grow in the absence of atmospheric oxygen
and obtain oxygen from oxygen-containing compounds? - Answer-anaerobes
What is the temperature at which bacteria grow best known as? - Answer-optium
On blood sugar plates a small zone of alpha hemolysis surrounded by a zone of beta
hemolysis after refrigeration is known as what type of hemolysis? - Answer-alpha-prime
What is the most effective method of sterilization? - Answer-autoclaving
What is used for quality control for the dry heat oven? - Answer-Bacillus subtilis
Media that cannot be heated can be sterilized by what alternate method? - Answer-
filtration
What disinfectant is the most effective germicide against bacteria, spores tubercle
bacilli, fungi, and viruses? - Answer-chlorine bleach
with Correct Answers
What organism is NOT OXIDASE POSITIVE? - Answer-Yersinia enterocolitica
Which organisms are oxidase positive? - Answer-Aeromonas hydrophilia,
Pseudomonas aeruginosa, Vibrio parahaemolyticus
Rice water stools often contain a pure culture of what organism? - Answer-Vibrio
cholerae
What is the reagent used for the string test? - Answer-0.5% sodium deoxcholate
What allows visibility of acid production by oxidizers in oxidation fermentation (OF)
medium? - Answer-peptone content is low
How many tubes of OF media is (are) inoculated, and under what atomospheric
conditions? - Answer-two tubes, one covered with oil so that air is excluded
Which organism is part of the normal flora of the skin? - Answer-Acintobacter
calcoaceticus
Which organism is oxidase positive? - Answer-Pseudomonas aeruginosa
Which organisms are oxidase negative? - Answer-Gardnerella vaginalis, Acinetobacter
calcoaceticus, Stenotrophomonas maltophilia
What is an acceptible anaerobic specimen? - Answer-body fluid submitted in a syringe
Naegler agar is selective medium for which organism? - Answer-Clostridium
Which Gram-negative anaerobe is resistant to penicillin? - Answer-Bacteroides fragilis
what best describes Propionibacterium? - Answer-anaerobic, Gram-positive bacilli
What Clostridium produces a double zone of hemolysis around colonies on blood agar?
- Answer-C. perfringens
Which Clostridium produces spores that are usually round and terminal? - Answer-C.
ramosum
, Which anaerobic, Gram-positive rod produces terminal "tennis racket" spores? -
Answer-Clostridium tetani
What species of Clostridium causes antimicrobial-associated diarrhea? - Answer-C.
Difficile
Which Gram-negative, anaerobic cocci produces a red fluorescence under ultraviolet
light? - Answer-Veillonella
What best describes Peptococcus? - Answer-anaerobic, Gram-positive cocci
What term describes the morphology of organisms that vary in size and shape? -
Answer-pleomorphic
Capsules are the basis of which test? - Answer-serotyping
A mucoid colony on blood agar medium indicates that which characteristic may be
present? - Answer-organism has a capsule
What are dark staining granules called? - Answer-metachromatic
Which organisms are non motile? - Answer-Shigella and Klebsiella
In the bacterial growth cycle, growth ceases because nutrients are exhausted or toxic
metabolic products have accumulated in what phase? - Answer-stationary phase
What genera of bacteria form spores? - Answer-Bacillus, Clostridium
What term is used to describe bacteria that grow in the absence of atmospheric oxygen
and obtain oxygen from oxygen-containing compounds? - Answer-anaerobes
What is the temperature at which bacteria grow best known as? - Answer-optium
On blood sugar plates a small zone of alpha hemolysis surrounded by a zone of beta
hemolysis after refrigeration is known as what type of hemolysis? - Answer-alpha-prime
What is the most effective method of sterilization? - Answer-autoclaving
What is used for quality control for the dry heat oven? - Answer-Bacillus subtilis
Media that cannot be heated can be sterilized by what alternate method? - Answer-
filtration
What disinfectant is the most effective germicide against bacteria, spores tubercle
bacilli, fungi, and viruses? - Answer-chlorine bleach
