• Clinical science

Melioidosis (Burkholderia pseudomallei infection)

Summary

Melioidosis, also known as Whitmore disease, is an infectious disease caused by the bacterium Burkholderia pseudomallei. It is predominantly seen in tropical climates in Southeast Asia and Northern Australia, where it is transmitted via contact with contaminated water or soil. The clinical course of Melioidosis can vary greatly, ranging from asymptomatic disease to acute or chronic infection. In some cases, there is a latency period after initial infection, followed by reactivation. Symptomatic disease manifests with localized symptoms, pulmonary symptoms, or disseminated systemic symptoms. Antimicrobial therapy is the mainstay of treatment; in severe cases, adjunct therapy is also required. There are no vaccinations available against B. pseudomallei; prevention involves avoiding potentially contaminated sources, wearing protective gear in environments where there is a risk of contracting the pathogen, and observing general contact measures when interacting with infected patients (e.g., gloves, gowns).

Epidemiology

  • Distribution: occurs in tropical climates, mainly in Southeast Asia (e.g., Thailand, Malaysia) and Northern Australia
  • Incidence: ∼ 150,000 case/year worldwide, with most cases occurring in wet seasons

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

  • Pathogen: Burkholderia pseudomallei
    • Facultative intracellular gram-negative bacterium
  • Transmission
    • Percutaneous inoculation: contact with contaminated soil or water (most common)
    • Inhalation, aspiration, or ingestion of contaminated dust or water
    • Person-to-person transmission is rare

References:[1][2]

Clinical features

  • Incubation period: 1–21 days (mean ∼ 9 days)
  • Most cases are subclinical or asymptomatic.
  • Symptomatic cases can be acute, chronic (> 2 months), or reactivations of latent infection.
  • Clinical features depend on the infected organ:

References:[1][3]

Diagnostics

  • Laboratory testing
  • Imaging
    • Chest radiography: may show signs of acute pneumonia
    • CT and MRI imaging: to identify abscess formation in multiple organs

References:[1]

Differential diagnoses

References:[1]

The differential diagnoses listed here are not exhaustive.

Treatment

References:[4][5]

Prevention

  • In endemic areas, contact with soil and standing water should be avoided (e.g., agricultural workers should wear boots).
  • Health care and laboratory workers should wear masks, gloves, and gowns to prevent infection.
  • No vaccination available

References:[6]