Denise - Oxidative GNBs (Acinetobacter, Burkholderia, Stenatrophomonas)

Question 1

How are gram negative bacilli categorised?

Answer 1

Fermentative and Oxidative

Question 2

What are the oxidative GNBs

Answer 2

Pseudomonas
Acinetobacter
Burkholderia
Stenotrophomonas

Question 3

How are the oxidative GNBs divided?

Answer 3

Oxidase negative and oxidase positive

Question 4

What GNBs are oxidase negative

Answer 4

Acinetobacter
Stenotrophomonas

Question 5

What GNBs are oxidase positive

Answer 5

Pseudomonas
Burkholderia

Question 6

What is the main species of Burkholderia studied

Answer 6

Burkholderia cepacia complex (BCC)

Question 7

Write about Burkholderia cepacia complex (BCC)
(7)

Answer 7

Natural environments

Non pathogenic in healthy humans

Chronic and sever respiratory infections in cystic fibrosis

First reported in the 1980s

Causes severe, necrotising pneumonia, “cepacia syndrome”

Intrinsically/naturally Multi drug resistant

Increased virulence and transmissability

Question 8

What infections does Burkholderia cause

Answer 8

Severe, necrotising pneumonia
Known as “cepacia syndrome”

Question 9

What are some of the clinical implications of B. cepacia in CF patients
(4)

Answer 9

Deteriorating lung function

More pulmonary exacerbations/hospital admissions

More IV antibiotics

Reduced life expectancy

Question 10

How does B. cepacia impact CF patients?
(3)

Answer 10

Hospital segregation (between impatients and outpatients)

Social isolation in CF community

Implications for transplantation

Question 11

How do we isolate Burkholderia cepacia
(4)

Answer 11

We use Burkholderia cepacia Selective Agar

Its an aerobic Oxidase positive GNB

Its a non lactose fermenter

Confirm identification by molecular ID

Question 12

Can we use the Maldi/Vitek to ID B. cepacia

Answer 12

No there are issues using the Maldi and Vitek

Question 13

What species of Acinetobacter is studied in detail?

Answer 13

Acinetobacter baumannii

Question 14

Write a note on Acinetobacter baumannii
(5)

Answer 14

Ubiquitous in the environment (found everywhere)

Emerged as a healthcare-associated pathogen

Outbreaks within and across healthcare facilities

Resistance to multiple antimicrobial agents MDR

CRAB is becoming more common

Question 15

What is CRAB

Answer 15

Carbapenem Resistant Acinetobacter baumannii

Question 16

What species of Stenotrophomonas is studied?

Answer 16

Maltophilia

Question 17

Write a note on Stenotrophomonas maltophilia
(7)

Answer 17

Closely related to Pseudomonas

Not virulent

Inherent MDR

Causes Pneumonia and BSI in the immunocompromised

Increased in Cystic Fibrosis infections

Co infections with Pseudomonas

Commonly found in soil

Reservoir in HAI is poorly understood

Question 18

What type of infections does Stenotrophomonas maltophilia
(3)

Answer 18

Causes Pneumonia and BSI in the immunocompromised

Increased in Cystic Fibrosis infections

Co infections with Pseudomonas

Question 19

How do you identify Stenatrophomonas species or Acinetobacter species in the laboratory?
(4)

Answer 19

They are oxidase negative GNBs

They are non lactose fermenters

They are aerobic

They won’t grow on Burkholderia selective agar or cetramide agar

Question 20

Can we use the Maldi/Vitek to identify Stenatrophomonas or Acinetobacter

Answer 20

No there are issues with using both

Question 21

How do we carry out antimicrobial susceptibility testing for any of these organisms?
(2)

Answer 21

Automated antimicrobial susceptibility is not reliable

Must use manual disk diffusion on E-tests