melioidosis

Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei. The organism is found in soil and surface water in tropical climates and is most commonly reported in Southeast Asia and northern Australia, with sporadic cases elsewhere.

Transmission occurs through contact with contaminated soil or water, via skin wounds, inhalation of contaminated dust or droplets, or ingestion. People with certain conditions, such as diabetes mellitus, chronic kidney or liver disease, alcoholism, immunosuppression, or exposure to soil and water through farming, are at higher risk. The incubation period ranges from a few days to months, and latent infection can reactivate after years.

Clinical presentation varies widely. It can cause acute illness with pneumonia or septicemia, as well as localized infections such as skin ulcers, abscesses in the liver or spleen, or bone and joint infections. The disease can be disseminated and may resemble tuberculosis or other chronic infections; meningitis is uncommon but serious when it occurs.

Diagnosis relies on culture of the organism from blood, sputum, urine, pus, or other body fluids. Microscopy and biochemical tests support identification, and molecular methods (PCR) can aid detection. Serology is less reliable due to widespread exposure in some regions. Early recognition in endemic areas is important to guide therapy and reduce mortality.

Treatment requires two phases. Initial therapy uses intravenous antibiotics such as ceftazidime or a carbapenem (for example, meropenem) for at least 10–14 days, longer in severe disease. This is followed by a prolonged eradication phase with oral antibiotics, typically trimethoprim-sulfamethoxazole, for 3–6 months, sometimes combined with doxycycline or amoxicillin-clavulanate. Relapses are possible if treatment is incomplete.

Public health notes: melioidosis is endemic in parts of Asia and Australia and occurs sporadically elsewhere. Prevention focuses on reducing exposure to contaminated soil and water, especially for high-risk individuals; no widely available vaccine exists.