Melioidosis

Question 1

Melioidosis - causative bacteria

Answer 1

Burkholderia pseudomallei:
Gram negative bacillus, oxidase positive
Environmental saprophyte

Question 2

Burkholderia pseudomallei

Answer 2

Gram negative bacillus,oxidase positive
Environmental saprophyte
Opportunistic pathogen [80% immunocompromised]:
-DM x10 risk
-Renal failure
-Steroids
-Alcohol dependency

Question 3

Melioidosis - epidemiology

Answer 3

Greatest burden [44%] predicted to be in Southeast Asia

Question 4

Melioidosis - transmission

Answer 4

Direct contact with contaminated soil and water

Question 5

Melioidosis - S+S

Answer 5

Wide range of signs and symptoms

Localised disease - fever, localised pain, ulceration, abscess

Respiratory disease - pneumonia, abscess, pleuritis

Cardiovascular - bacteraemia, pericarditis, mycotic anuerysm

Urinary tract, GI [liver abscess], CNS and MSK involvement can all occur

Note:
-Prostatic abscess = found in 20% of males with melioidosis in Australia
-Parotid abscess = found in children in SE Asia

Question 6

Melioidosis - diagnosis

Answer 6

Culture - gold standard [ashdown medium]
Serology - latex agglutination [less useful in endemic as may have antibodies]
PCR - type 3 secretion system target, not routinely used
Antigen detection test
3 disc test - inherently resistant to colistin and gentamicin, but sensitive to co-amoxiclav

Question 7

Melioidosis - treatment

Answer 7

Intensive phase - >2 weeks of IV beta-lactam [ceftazidime or carbapenem]

Eradication phase - >12 weeks oral co-trimoxazole