“Melioidosis” is a potentially fatal infectious disease caused by the environmental bacterium Burkholderia pseudomallei. Due to its diverse symptoms, melioidosis is often misdiagnosed, as these symptoms can imitate those of other tropical diseases.
It is spread through contact with contaminated soil, air, or water. Cases may increase after hurricanes, heavy rain, and other severe weather events.
History:-In 1911, pathologist Alfred Whitmore and his assistant C. S. Krishnaswami first described melioidosis as a “glanders-like” disease among morphine addicts in Rangoon, Burma. The disease was previously known as Whitmore’s disease. “melioidosis” was later coined by A.T. Stanton and W. Fletcher in 1921. It is derived from a Greek word that means “glanders-like disease.”
Caused by – Burkholderia pseudomallei is a facultative intracellular gram-negative bacterium widely distributed as an environmental saprophyte in soil and fresh water, particularly in endemic regions.
Transmission:- The predominant transmission mode is percutaneous inoculation during exposure to wet season soils or contaminated water, which may shift from inoculation to inhalation. Ingestion of water contaminated with B. pseudomallei . Person-to-person transmission is highly unusual, but transmission through blood transfusion or organ donation has not been reported.
Incubation Period: The incubation period for acute melioidosis following inoculating injury ranges from 1 to 21 days (mean 4 to 9 days).
Clinical Presentation:- Melioidosis is often referred to as “the great mimicker” because its signs and symptoms can be non-specific. The average incubation period for acute infections is around 9 days, but it can range from 1 to 21 days.
Sometimes, the illness may be localized to one area, presenting as an ulcer or skin sore. Symptoms can include fever, swelling, and muscle aches.
Melioidosis manifests more commonly as a lung infection. Symptoms may include cough, chest pain, high fever, headache, and loss of appetite.
In adults, pneumonia is the most frequent clinical presentation of melioidosis. Additionally, abscesses can occur in internal organs, particularly the spleen (often multifocal), kidneys, prostate, and liver. In children, suppurative parotitis is a joint presentation of melioidosis.
Diagnosis:-Gram stain of sputum shows purulent characteristics with bipolar staining resembling a “safety pin” appearance.
For culture, Ashdown’s agar containing gentamicin or Ashdown’s liquid transport broth with colistin allows for the selective growth of B. pseudomallei.
In patients with encephalomyelitis, CSF culture is often negative; in such cases, the diagnosis is made by culture of B. pseudomallei from other sites in an individual with CSF leukocytosis and consistent findings on imaging.
Treatment:- Drugs used for cure are ceftazidime, carbapenems, trimethoprim-sulfamethoxazole (TMP-SMX), and doxycycline.
The mortality rate among untreated patients can reach up to 90%, with many dying before a diagnosis is established. Consequently, the actual burden of this disease remains largely concealed.
