Burkholderia pseudomallei is a bacterium responsible for melioidosis, a serious infectious disease. This bacterium is commonly found in tropical and subtropical regions worldwide. Melioidosis is a concern due to its potential severity and diverse clinical presentations.
What is Melioidosis?
Melioidosis is a severe infectious disease caused by the bacterium Burkholderia pseudomallei. The disease can manifest in various forms, from localized infections to widespread illness affecting multiple organ systems. Approximately 10% of individuals experience chronic symptoms lasting longer than two months.
The disease can present as a lung infection, skin ulcers, or abscesses in organs like the liver, spleen, or prostate. In its most severe form, melioidosis can lead to septicemia, a bloodstream infection that can result in septic shock and be fatal. Prompt medical attention is important when melioidosis is suspected.
How People Get Infected
Burkholderia pseudomallei naturally resides in contaminated soil and water, particularly in tropical and subtropical climates like Southeast Asia, northern Australia, and parts of Central and South America. The bacterium can survive in water for many years and is resistant to harsh environmental conditions. Cases often increase after heavy rainfall or severe weather, as these conditions bring bacteria to the surface and spread them more easily.
People typically acquire melioidosis through direct contact with contaminated soil or water. Common routes include inhaling contaminated dust or water droplets, especially during activities that disturb the soil. The bacterium can also enter the body through breaks in the skin, such as cuts or scrapes. Ingestion of contaminated water is another possible, though less common, route. Person-to-person transmission is rare, but can occur through contact with blood or bodily fluids from an infected person.
Recognizing Melioidosis
The signs and symptoms of melioidosis are highly variable, making diagnosis challenging as they can mimic other common diseases like tuberculosis. Symptoms usually appear within one to four weeks after exposure, but can develop months or even years later. The disease can affect a single body system or spread throughout the body.
Common manifestations include lung infections, ranging from mild bronchitis-like symptoms to severe pneumonia, often with cough, chest pain, and high fever. Localized infections may present as skin ulcers or abscesses, characterized by swelling, pain, and fever. If the infection spreads, it can cause abscesses in internal organs like the liver, spleen, or prostate, leading to symptoms such as abdominal pain, weight loss, or joint pain.
Diagnosis primarily relies on laboratory tests, with bacterial culture from clinical samples being the definitive method. Samples of blood, urine, sputum, pus from abscesses, or tissue can be collected and cultured to identify Burkholderia pseudomallei. While serological tests exist, their utility in acute diagnosis is limited, especially in endemic areas, due to varying antibody levels and potential for false positives. Suspected cases require specific laboratory media and specialized expertise for identification.
Treating and Preventing Melioidosis
Treatment for melioidosis involves a prolonged course of antibiotics, typically administered in two phases to eradicate the bacterium and prevent relapse. The initial intensive phase usually involves intravenous (IV) antibiotics for 10 to 14 days, extending to several weeks for severe infections like deep-seated abscesses, extensive lung disease, or neurological melioidosis. Preferred IV antibiotics include ceftazidime or meropenem, with meropenem often reserved for critically ill patients.
Following the intensive phase, an oral eradication phase is necessary, typically lasting three to six months, to prevent recurrence. Trimethoprim/sulfamethoxazole (co-trimoxazole) is commonly used, with amoxicillin/clavulanic acid (co-amoxiclav) as an alternative. Early diagnosis and appropriate, prolonged treatment are important, as untreated or improperly treated melioidosis can have a high mortality rate, sometimes exceeding 40%. Supportive care, including drainage of abscesses, also plays a role.
Preventing melioidosis focuses on minimizing exposure to contaminated soil and water, especially in endemic regions during wet seasons or after heavy rainfall. Individuals with open skin wounds or underlying health conditions like diabetes or kidney disease should avoid contact with soil and standing water. Wearing protective footwear and gloves during agricultural work, gardening, or other activities involving contact with soil or muddy water can help prevent infection through skin abrasions. Additionally, avoid drinking unchlorinated or untreated water where the bacterium is prevalent.