Genus Burkholderia

Question 1

Classification

Answer 1

Family: Burkholderiaceae

Genus: burkholderia

• Five species
• Formally classified as pseudomonas

Only B.Cepacia and B.pseudomallei are human pathogens

B. Pseudomallei : causative agent of meliodosis (Whitmore’s disease)
B.cepacia: important pathogen of pulmonary infections in people with cystic fibrosis

Question 2

Morphology

Answer 2

Gram negative rod
Motile (single or multipolar flagella)
-B.mallei is non motile

Question 3

B. Pseudomallei

Answer 3

Habitat: soil and surface water

Opportunistic pathogen
Resistant to many antibiotics

Characteristics: facultative anaerobic

Disease: meliodosis (acute, subacute, chronic, latent)

Endemic area: SEA, northern Australia

Symptom: variable

Virulence factors: siderophore, motility, type III secretion system

Diagnosis: serum test, culture of bacteria, PCR

Risk factor: type II diabetes and kidney failure

Treatment:
Severe infection -> TMP/SMX + ceftazidime
Long lasting: 8 weeks to several months

vaccine: not available

Question 4

B.cepacia

Answer 4

Habitat:

• Colonise moist environmental surfaces
• Nosocomial infections

Growth characteristics:

• aerobic
• oxidase negative
• dry yellow colonies

Virulence factors: 
- Protease
- Catalase
- adhesins- pili 
In vitro, the lipid A of these bacteria stimulates pro-inflammatory cytokines tenfold more than P.aeruginosa lipid A 

Disease:

• respiratory tract infections (CF patients)
• UTI in catheterised patients
• peritonitis
• septic arthritis
• septicemia (patients with contaminated intravascular catheters)

Treatment:

• 3rd gen cephalosporins
• carbapenems
• TMP/SMX