Burkholderia pseudomallei: Difference between revisions
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Burkholderia pseudomallei
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** Can use selective colistin or polymyxin B |
** Can use selective colistin or polymyxin B |
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** On sheep blood agar, grows as small, smooth, cream-coloured colony with metallic sheen |
** On sheep blood agar, grows as small, smooth, cream-coloured colony with metallic sheen |
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** May develop a dry and '''wrinkled''' appearance after 1 to 2 days of incubation |
** May develop a dry and '''wrinkled''' appearance after 1 to 2 days of incubation |
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* MALDI-ToF is ''not'' reliable for identifying it |
* MALDI-ToF is ''not'' reliable for identifying it |
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* Other methods |
* Other methods |
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Revision as of 23:36, 19 July 2020
Background
Microbiology
- Oxidase-positive, indole-negative Stain::Gram-negative]] bacillus with "safety pin" appearance
- Non-hemolytic
- Colonies are dry and wrinkly
Epidemiology
- Humans and animals
- Important cause of death in SE Asia and northern Australia
- Up to 80% seroprevalence in Thailand, mostly asymptomatic
- Sporadic cases elsewhere
- May have latent disease with reactivation much later
- Acquired by percutaneous inoculation, inhalation (esp. lab workers), and ingestion
- Risk factors for clinical disease
- Diabetes
- Heavy alcohol use
- Chronic lung disease
- Chronic kidney disease
- Treatment with glucocorticoids
- Cancer
- Thalassemia
Clinical Manifestations
- Incubation period 9 days (range 1 to 21 days)
- Presentations can vary from asymptomatic, skin ulcers, abscesses, latent infection, chronic pneumonia (similar to TB), or fulminant shock
- Pneumonia (50%)
- GU infection (15%)
- Skin (15%)
- Primary bacteremia (10%)
- Septic arthritis/OM (3-5%)
- Neuro (3-5%)
- About 20% of clinical cases with develop septic shock
Diagnosis
- Culture
- Blood, throat, and urine cultures from all patients with suspected melioidosis
- Grows on blood agar, MacConkey, etc. (i.e. not a fastidious organism)
- Can use selective colistin or polymyxin B
- On sheep blood agar, grows as small, smooth, cream-coloured colony with metallic sheen
- May develop a dry and wrinkled appearance after 1 to 2 days of incubation
- MALDI-ToF is not reliable for identifying it
- Other methods
- PCR
- Immunofluorescence and latex agglutination
- Serology (acute/convalescent)
Management
- Intrinsic resistance to many antibiotics, especially using efflux pumps
- Ceftazidime
- Amoxicillin-clavulanic acid
- TMP-SMX
Biosafety
- Lab workers can have aerosol exposure
- May need prophylaxis in high-risk patients
- Septra or doxy or amox/clav
- Needs to be sent to CDC via NML
References
- ^ Bart J. Currie, Linda Ward, Allen C. Cheng. David Joseph Diemert. The Epidemiology and Clinical Spectrum of Melioidosis: 540 Cases from the 20 Year Darwin Prospective Study. PLoS Neglected Tropical Diseases. 2010;4(11):e900. doi:10.1371/journal.pntd.0000900.
