Bacteria

Melioidosis

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Melioidosis, Burkholderia pseudomallei

  • See Also
  1. Aerobic Gram Negative Rod
  2. Nodular Lymphangitis
  3. Glanders
  • Epidemiology
  1. Primarily occurs in southeast asia, Australia
  2. Worldwide deaths per year: 89,000
  • Pathophysiology
  1. Burkholderia pseudomallei is an Aerobic Gram Negative Rod
    1. B. pseudomallei is an opportunistic, facultative intracellular, motile saprophyte
    2. Potent pathogen with many virulence factors and broad Antibiotic Resistance
  2. B. pseudomallei contaminates soil and water in tropical regions (esp. Southeast Asia, Australia)
  • Risk Factors
  • Systemic Disease
  1. No known risk factors in 80% of children and 20% of adults
  2. Zoonotic transmission to humans (e.g. from livestock) is extremely rare
  3. Contaminated soil or water exposure (esp. during rainy season)
  4. Diabetes Mellitus (RR 12)
  5. Male gender
  6. Age >45 years
  7. Alcohol Use Disorder
  8. Liver Disease
  9. Chronic lung disease
  10. Chronic Kidney Disease
  11. Thalassemia
  12. Immunosuppression
  13. Corticosteroid Use
  • Signs
  • Localized
  1. Incubation Period: 9 days (range 1 to 21 days)
  2. Skin
    1. Single, chronic non-healing ulcer
    2. Lymphadenopathy may be present
  • Signs
  • Systemic (Melioidosis)
  1. On hospital admission, bacteremia in 40-60% and Sepsis in 20%
  2. Occult infection in 10% of cases
  3. Pneumonia (40-60%)
  4. Broad end-organ dissemination
    1. Splenic Abscess
    2. Prostate abscess
    3. Liver Abscess
    4. Kidney abscess
  • Differential Diagnosis
  1. Nodular Lymphangitis
  2. Glanders
  • Labs
  • Diagnosis
  1. Blood Culture
  2. Serology is less accurate
  • Management
  • Systemic Disease
  1. See Sepsis
  2. Early aggressive management of systemic disease is critical
  3. Intravenous Antibiotics
    1. Ceftazidime
    2. Meropenem
    3. Imipenem
    4. Ampicillin Sulbactam (Unasyn)
  4. Oral Antibiotics (Bacteriostatic, but high susceptibility)
    1. Trimethoprim–sulfamethoxazole
    2. Doxycycline
    3. Amoxicillin Clavulanate (Augmentin)
  5. Other Antibiotics that are less effective clinically (despite in vitro sensitivity)
    1. Piperacillin
    2. Ceftriaxone
    3. Cefotaxime
  1. Indications
    1. High-risk exposure to B. pseudomallei-contaminated materials via penetrating injuries, or to mouth, eyes
  2. Antibiotics for 21 day duration
    1. Trimethoprim–sulfamethoxazole (preferred)
    2. Doxycycline
    3. Amoxicillin Clavulanate (Augmentin)
  • Prognosis
  1. Systemic disease mortality 10% with modern ICU care (40% in many endemic regions)
  • Prevention
  1. See Prevention of Waterborne Illness
  2. See Water Disinfection
  3. Avoid direct soil and water contact at the start of each rainy season (esp. high risk groups)
  4. Protective clothing (gloves, boots) for higher risk exposures (e.g. rice farmers in Thailand)
  • References
  1. Wiersinga (2018) Nat Rev Dis Primers 4:17107 +PMID: 29388572 [PubMed]