An environmental gram-negative bacillus Burkholderia pseudomallei that causes a characteristic pneumonia with multiple abscesses and a mortality rate of up to 40%.
An important cause of community acquired sepsis in Southeast Asia and northern Australia.
A potentially fatal disease.
The agent is mainly distributed in tropical regions worldwide between the latitude of 20° north and 20° south.
Burkholderia pseudomallei naturally occurs in soil and water in many tropical and subtropical regions.
Endemic in Thailand, Malaysia, Singapore, Vietnam, Cambodia, and Laos.
Exposure to this bacterium occurs through inhalation, ingestion or the percutaneous route.
It’s distribution is expanding globally, reflecting improved diagnostic and microbiologic testing, and increased numbers of cases in travelers and returning military personnel.
B. pseudomallei contains over 40 species.
Can invade, survive, and replicate in a range of phagocytic and non phagocytic cells.
Intracellular behavior is crucial for disease pathogenesis.
Major regions where the process is endemic is northern Australia and Northeast Thailand with incidence rates up to 50 cases per hundred thousand people.
The third most common cause of death from infectious disease in Northeast Thailand.
Affects persons in regular contact with soil and water.
Infection occurs by means of contaminated soil or water exposure by percutaneous inoculation, inhalation, or ingestion.
Symptoms typically appear within 21 days after exposure, with diverse clinical manifestations, mimicking those of other diseases.
US cases are rare and are rare for related to travel to regions in which meliodosis is endemic.
Can manifest as a wide range of clinical syndromes including: skin abscesses, pneumonia, generalized sepsis with or without multiple organ abscesses, genitourinary infection, and encephalomyelitis.
Risk factors include: diabetes, alcohol use, COPD, chronic renal disease, thalassemia, exposure to steroids, and cancer.
Up to 80% of patients with infection have one or more risk factors and should be considered an opportunistic infection.
A predominantly seasonal infection with 75-81% of cases occurring during the rainy season.
Can occur at any age group but the incidence peaks between ages 40-60 years.
Can occur in children and can be transmitted from breastmilk to infants.
Incubation period has a mean of nine days, with a range of 1-21 days.
Rare in the US, is approximately a dozen cases reported each year and predominantly associated with travel to endemic areas.
Infection with B. pseudomallei has variable manifestations ranging from an acute fulminant septic process to a chronic infection.
Chronic infection with symptoms for greater than 2 months accounts for 11% of cases and can be confused with malignancy or tuberculosis.
The primary presentation is pneumonia in greater than 50% of cases, followed by urinary infection, skin infection, bacteremia without locating a focus of disease, septic arthritis, osteomyelitis, and rarely neurological involvement.
Over half of patients have bacteremia on presentation.
Septic shock develops in approximately one fifth of patients.
Abscesses in viscera, and foci of disease in bones and lungs are common.