Melioidosis Guide, Meaning , Facts, Information and Description
Melioidosis, also known as pseudoglanders and Whitmore's disease is an uncommon infectious disease caused by a Gram-negative bacterium, Burkholderia pseudomallei, found in soil and water. It exists in acute and chronic forms.The causative organism, Burkholderia pseudomallei, was thought to be a member of the Pseudomonas genus and was previously known as Pseudomonas pseudomallei. This organism is similar to Burkholderia mallei, the organism that causes glanders. Another closely-related but less virulent bacterium is found in Thailand and is called Burkholderia thailandensis.
Melioidosis is endemic in parts of south east Asia and northern Australia. Its true extent has not been completely defined but it has been noted before in Africa, India, parts of the Middle East and Central and South America. It affects humans as well as other animals such as goats, sheep, horses and cattle. The mode of infection is usually either through an infected laceration or burn or through inhalation of aerosolized B. pseudomallei.
There has also been interest in melioidosis because it has the potential to be developed as a biological weapon.
A patient with active melioidosis usually presents with fever. There may be pains in multiple sites around his/her body due to bacteremia and abscess formation. Patients with melioidosis usually have risk factors for disease, such as diabetes, thalassemia or renal disease. However, otherwise healthy patients, including children, may also get melioidosis.
If there is pulmonary involvement, there may be signs and symptoms of pneumonia.
If Hepatic or splenic abscesses are present, the patient may present with abdominal pain. If there are brain abscesses present, the patient may present with neurological signs and symptoms. An encephalomyelitis syndrome is recognised in northern Australia.
Melioidosis may also cause osteomyelitis and present with bony pain.
In Thailand, parotid abscesses in children are common.
A definitive diagnosis can be made by growing B. pseudomallei from blood cultures or from pus aspirated from an abscess.
There is also a serological test for melioidosis.
If clinically indicated, CT scans (or, in some cases, ultrasound scans) of the thorax and abdomen are useful to investigate for the presence of abscesses and to rule out other diseases.
Symptoms and signs
Patients with chronic or latent melioidosis may be symptom free for many years.Diagnosis
A definite history of contact with soil or animals may not be elicited as melioidosis can be dormant for many years before becoming acute. Attention should be paid to a history of travel to endemic areas in returned travellers. Patients with diabetes mellitus often have a more serious presentation of melioidosis.Treatment
Intravenous ceftazidime is the drug of choice for treatment of acute melioidosis. Intravenous amoxicillin-clavulanate and imipenem are also active. Intravenous antibiotics should be given for at least 10-14 days. Following the treatment of the acute disease, antibiotics such as bactrim may need to be given for a period of weeks to months to clear the organism from the body to prevent a recurrence.Prognosis
Before the era of modern antibiotics, the septicemic form of melioidosis had a high mortality rate exceeding 90%. With modern antibiotics, the mortality rate is about 10% for uncomplicated cases and up to 80% for cases with severe sepsis.