Burkholderia pseudomallei: Difference between revisions

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Burkholderia pseudomallei
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= Microbiology =
== Microbiology ==


* Oxidase positive, indole-negative Gram-negative rod with "'''safety pin'''" appearance
* Oxidase positive, indole-negative Gram-negative rod with "'''safety pin'''" appearance
* Non-hemolytic
* Non-hemolytic


= Epidemiology =
== Epidemiology ==


* Humans and animals
* Humans and animals
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** Thalassemia
** Thalassemia


= Clinical Presentation =
== Clinical Presentation ==


* Incubation period 9 days (range 1 to 21 days)
* Incubation period 9 days (range 1 to 21 days)
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* About 20% of clinical cases with develop septic shock
* About 20% of clinical cases with develop septic shock


= Diagnosis =
== Diagnosis ==


* Culture
* Culture
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** Serology (acute/convalescent)
** Serology (acute/convalescent)


= Management =
== Management ==


* Intrinsic resistance to many antibiotics, especially using efflux pumps
* Intrinsic resistance to many antibiotics, especially using efflux pumps
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* TMP-SMX
* TMP-SMX


= Biosafety =
== Biosafety ==


* Lab workers can have aerosol exposure
* Lab workers can have aerosol exposure

Revision as of 20:13, 15 August 2019

Microbiology

  • Oxidase positive, indole-negative Gram-negative rod with "safety pin" appearance
  • Non-hemolytic

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 Presentation

  • 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
  • Monitor with serology at baseline, weeks 1 2 4 and 6 post-exposure
    • Needs to be sent to CDC via NML
  • References

    1. ^  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.