UAMS MICRO EXAM 3 QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS ALREADY PASSED!!!
What reaction results in open and closed OF tubes indicate a carbohydrate
FERMENTER, and what is a classic organism example?
✔✔ Open Tube: Acid / Yellow
✔✔ Closed (Oil-Overlay) Tube: Acid / Yellow
✔✔ Metabolic Pathway: Utilizes glucose in both aerobic and anaerobic
conditions.
✔✔ Classic Example: Members of Enterobacteriaceae (e.g., E. coli, Klebsiella,
Enterobacter).
What reaction results in open and closed OF tubes indicate a carbohydrate
OXIDIZER (non-fermenter), and what is a classic organism example?
✔✔ Open Tube: Acid / Yellow (aerobic oxidation at the surface)
✔✔ Closed (Oil-Overlay) Tube: No Acid / Green or Blue (unable to ferment
anaerobically)
✔✔ Metabolic Pathway: Oxidizes glucose aerobically only.
✔✔ Classic Example: Pseudomonas aeruginosa (and other non-fermenting
Gram-negative bacilli like Burkholderia).
What reaction results in open and closed OF tubes indicate an Asaccharolytic
/ Non-utilizer organism?
✔✔ Open Tube: No Acid / Green or Blue (or alkaline/blue at top due to peptone
breakdown)
✔✔ Closed (Oil-Overlay) Tube: No Acid / Green or Blue
✔✔ Classic Example: Acinetobacter lwoffii or Moraxella species.
,OF Reaction for Non-oxidizers
Open tube: No acid (green/blue)
Closed tube: No acid (green/blue)
Ex: Assachrolytic Acinetobacter
Nitrate Reduction Test:
Nitrate reduced to Nitrite.
(+) result; red color within 30 min of addition of Reagents A and B.
Ex. E. coli.
Nitrate Reduction Test:
Nitrogen gas produced.
(+) results. Red color does not appear with addition of Reagents A and B. Medium
stays colorless when zinc dust is added.
Ex: Pseudomonas aeruginosa.
,Nitrate Reduction Test:
Nitrate not reduced.
A negative result. A red color appears after the addition of zinc dust.
Ex: Acinetobacter.
Pseudomonas aeruginosa Diseases
Causes diseases such as swimmer's ear and infections in immunocompromised
patients (CF and burn patients).
Pseudomonas aeruginosa Morphology
Morphology: Large, irregularly shaped, metallic sheen. Produces Pyocyanin. Beta
hemolytic on sheep BAP; Grows on MAC (lactose neg).
Grows on routine media including MAC.
P. aeruginosa Key ID Tests
Glucose oxidizer
Oxidase positive
Growth at 42 degrees
TSI: A/NC
Produces pyocyanin
, Pseudomonas aeruginosa
What is the most commonly isolated NFB?
Acinetobacter
What is the 2nd most commonly isolated NFB?
Which species of Acinetobacter are saccharolytic and which are assacharolytic?
A. baumannii = saccharolytic
A. lwoffii = assaccharolytic
Acinetobacter Key ID Tests
Oxidase negative
Nitrate negative
Glucose utilization
Which microbe can appear as pairs of plump coccobacilli or as filamentous rods?
Acinetobacter
What is the 3rd most commonly isolated NFB?
ANSWERS WITH COMPLETE
SOLUTIONS ALREADY PASSED!!!
What reaction results in open and closed OF tubes indicate a carbohydrate
FERMENTER, and what is a classic organism example?
✔✔ Open Tube: Acid / Yellow
✔✔ Closed (Oil-Overlay) Tube: Acid / Yellow
✔✔ Metabolic Pathway: Utilizes glucose in both aerobic and anaerobic
conditions.
✔✔ Classic Example: Members of Enterobacteriaceae (e.g., E. coli, Klebsiella,
Enterobacter).
What reaction results in open and closed OF tubes indicate a carbohydrate
OXIDIZER (non-fermenter), and what is a classic organism example?
✔✔ Open Tube: Acid / Yellow (aerobic oxidation at the surface)
✔✔ Closed (Oil-Overlay) Tube: No Acid / Green or Blue (unable to ferment
anaerobically)
✔✔ Metabolic Pathway: Oxidizes glucose aerobically only.
✔✔ Classic Example: Pseudomonas aeruginosa (and other non-fermenting
Gram-negative bacilli like Burkholderia).
What reaction results in open and closed OF tubes indicate an Asaccharolytic
/ Non-utilizer organism?
✔✔ Open Tube: No Acid / Green or Blue (or alkaline/blue at top due to peptone
breakdown)
✔✔ Closed (Oil-Overlay) Tube: No Acid / Green or Blue
✔✔ Classic Example: Acinetobacter lwoffii or Moraxella species.
,OF Reaction for Non-oxidizers
Open tube: No acid (green/blue)
Closed tube: No acid (green/blue)
Ex: Assachrolytic Acinetobacter
Nitrate Reduction Test:
Nitrate reduced to Nitrite.
(+) result; red color within 30 min of addition of Reagents A and B.
Ex. E. coli.
Nitrate Reduction Test:
Nitrogen gas produced.
(+) results. Red color does not appear with addition of Reagents A and B. Medium
stays colorless when zinc dust is added.
Ex: Pseudomonas aeruginosa.
,Nitrate Reduction Test:
Nitrate not reduced.
A negative result. A red color appears after the addition of zinc dust.
Ex: Acinetobacter.
Pseudomonas aeruginosa Diseases
Causes diseases such as swimmer's ear and infections in immunocompromised
patients (CF and burn patients).
Pseudomonas aeruginosa Morphology
Morphology: Large, irregularly shaped, metallic sheen. Produces Pyocyanin. Beta
hemolytic on sheep BAP; Grows on MAC (lactose neg).
Grows on routine media including MAC.
P. aeruginosa Key ID Tests
Glucose oxidizer
Oxidase positive
Growth at 42 degrees
TSI: A/NC
Produces pyocyanin
, Pseudomonas aeruginosa
What is the most commonly isolated NFB?
Acinetobacter
What is the 2nd most commonly isolated NFB?
Which species of Acinetobacter are saccharolytic and which are assacharolytic?
A. baumannii = saccharolytic
A. lwoffii = assaccharolytic
Acinetobacter Key ID Tests
Oxidase negative
Nitrate negative
Glucose utilization
Which microbe can appear as pairs of plump coccobacilli or as filamentous rods?
Acinetobacter
What is the 3rd most commonly isolated NFB?
