Module 14

Question 1

What is the cellular morphology of Pseudomonas aeruginosa?

Answer 1

Thing gram neg rods, slightly curved

One polar flagellum

Capsules

Question 2

What are the growth requirements for Pseudomonas aeruginosa?

Answer 2

Obligate aerobe

Optimum temp is 35°C but can grow up to 42°C and at low temps as well

Growth in BAP, MAC and nutrient agar

Question 3

What pigment do 90% of Pseudomonas aeruginosa produce?

Answer 3

Pyocyanin (blue-green)

Question 4

What kind of growth does Pseudomonas aeruginosa show?

Answer 4

BAP- large, beta hemolysis, irregular edges, metallic sheen (if infected with bacteriophage), blue-green pigment

MAC- NLF

Strong grape odour

Growth on moderately selective media for Enterobacteriaceae

Question 5

What are the ID tests for Pseudomonas aeruginosa?

Answer 5

Ox pos

Glc OF +/-

Darting motility

K/K

Cit pos

Urea pos

ADH pos

Growth at 42°C

Question 6

What is the clinical significance of Pseudomonas aeruginosa?

Answer 6

Moist environments

Normal/transient stool flora

Swimmer’s ear, pneumonia, UTI, folliculitis

Colonization of cystic fibrosis patients early in life

Question 7

What is the antimicrobial susceptibility of Pseudomonas aeruginosa?

Answer 7

Very resistant

Combo of B lactam antibiotic and aminoglycoside

Testing always required

Question 8

How does cation concentration affect the testing of Pseudomonas antimicrobials?

Answer 8

Low- falsely resistant

High- falsely sensitive

Question 9

What is the cellular morphology of Stenotrophomonas maltophilia?

Answer 9

Gram neg rods

Lophotrichous flagella

Question 10

What kind of grow does Stenotrophomonas maltophilia show?

Answer 10

BAP- 2-4mm colonies, lavender green

MAC- NLF

Ammonia odour

Question 11

What are the ID tests for Stenotrophomonas maltophilia?

Answer 11

Ox neg

Glc OF +/-

Malt OF +/-

Lac OF +/-

Motile with rapid directional movement

K/K

Cit variable

Urease usually pos

ADH neg

Lys pos

DNase pos

Question 12

What is the clinical significance of Stenotrophomonas maltophilia?

Answer 12

Moist environment

Colonize moist body sites

Serious infections in debilitated patients

Pneumonia, septicaemia, endocarditis, UTI, meningitis, wound infections

Question 13

What is the antimicrobial susceptibility of Stenotrophomonas maltophilia?

Answer 13

Trimethoprim-sulfamethoxazole (SXT)

Question 14

What is the cellular morphology of Acinetobacter baumannii?

Answer 14

Gram neg coccoid rods

No flagella

May resemble Neisseria or Moraxella

Question 15

What are the growth requirements for Acinetobacter baumannii?

Answer 15

Aerobes

Variable temp

Question 16

What kind of growth does Acinetobacter baumannii show?

Answer 16

BAP- small grey colonies, no hemolysis or pigment

MAC- NLF (pink tint after 48hrs)

Question 17

What is the ID for Acinetobacter baumannii?

Answer 17

Ox neg

Glc OF +/-

Lac OF +/-

Malt OF variable

Nonmotile

Cit usually pos

Urease variable

K/K

Lys neg

ADH neg

Question 18

What is the clinical significance of Acinetobacter baumannii?

Answer 18

Important nosocomial pathogen

Debilitated patients

Pneumonia, wound infections, UTI

Question 19

What is the antimicrobial susceptibility of Acinetobacter baumannii?

Answer 19

Testing always required

Imipenem

Meropenem

Amikacin

Polymixin B

Some tetracyclines

Question 20

What family does Pseudomonas aeruginosa belong to?

Answer 20

Pseudomonadineae