MELIOIDOSIS

Melioidosis – General Informations

It is an infection caused by the bacterium Burkholderia pseudomallei, and is also called Whitmore’s disease. Melioidosis is pathologically and clinically similar to glanders disease, but epidemiology and ecology they are different, glanders being contracted by humans from infected domestic animals. This disorder is endemic especially in Southeast Asia because it is a disease of tropical climates, where it is found in water, mud and soil, especially that of rice paddies. Most human cases arise from environmental exposure, not from animal contact, although many animal species like mammals, birds, and reptiles are susceptible, and may be rapidly fatal.

Infection usually occurs by inoculation through cuts and abrasions, or sometimes by aspiration or inhalation. Most cases occur in people with some underlying medical condition such as diabetes, chronic kidney or liver disease, or long term steroid treatment The organism is not known to have been the subject of weaponisation attempts. However, it could be a potential agent for bioterrorism as it can infect people by many diverse routes, is able to survive for long periods in the environment and can cause rapidly fatal infections. A likely route would be airborne spread. The incubation period in naturally acquired infections can vary from days to months to years. The incubation period after an aerosol attack is expected to be from 10-14 days. A few isolated cases of patients suffering from this particular disorder (medical condition) have occurred in the United States. Confirmed cases range from 0-5 each year and occur among travelers, immigrants, and intravenous drug users.

Melioidosis – Symptoms

There are different ways to categorize Melioidosis and it can be localized infection, pulmonary infection, bloodstream infection and chronic suppurative infection. Infections can be also unapparent. The time between exposure and appearance of clinical symptoms (the incubation period) it is not defined, but can be estimated from 2 days to many years. The acute localized infection is usually localized as a nodule and appears from inoculation through a skin lesion. The localized form of malioidosis usually produces general muscle aches and fever, and can progress rapidly to infect the bloodstream. The pulmonary infection can produce a clinical picture of mild bronchitis to severe pneumonia. The pulmonary form of this disorder is sometimes accompanied by a headache, anorexia, general muscle aches, soreness and high fever. Also, a common symptom of pulmonary infection is chest pain, but the hallmark of this form is nonproductive and productive cough with normal sputum.

The bloodstream infection usually affects patients with illness such as HIV, diabetes and renal failure and always results in septic shocks. The symptoms of bloodstream are respiratory distress, fever, development of filled lesions on the skin, disorientation, muscle tenderness, diarrhea, severe headache, and these can vary depending on the site of original infection. This is a short duration infection. Chronic suppurative infection is a form of Melioidosis that involves some organs of the body including joints, lymph nodes, viscera, brain, skin, lung, liver, spleen and bones. However, it is known that any medical disorder can trigger a variety of symptoms. Therefore, some of this medical condition's most uncommon symptoms have not been listed (mentioned) here. Ask your physician for further information.

Melioidosis – Treatment

All cases of Melioidosis, even mild disease, should be treated with initial intensive therapy (at least two weeks of intravenous therapy) followed by eradication therapy orally for a minimum of three months. There is no vaccine to prevent the disease. Person-to-person spread is rarely encountered but can occur, so these cases need to be isolated. The environmental nature of the organism makes the prevention of disease in endemic areas very difficult. Prophylactic antibiotics can be deliberate released in people who have been exposed but their value is still unknown, although it is a partial protective effect that was discovered in experimental animals. Persons with diabetes and skin lesions should avoid contact with soil and standing water in these areas. Wearing boots during agricultural work can prevent infection through the feet and lower legs. In health care settings, using common blood and body fluid precautions can prevent transmission. Melioidosis is endemic in Southeast Asia and northern Australia. It has been observed in the South Pacific, Africa, India, the Middle East, Central America, and South America.

The treatment used to cure Melioidosis is antibiotics and depends on the location of the disease. If the severe disease is not treated is always fatal, whereas infections have a much lower fatality rate (approximately 5%). Antibiotics can reduce the rate of mortality of severe disease to 40%, once it has been correctly diagnosed. To prevent the disease recurring, antibiotic treatment must continue for prolonged periods, necessary from 3 to 12 months. The organism that causes Melioidosis, Burkholderia pseudomallei, is usually very sensitive to imipenem, penicillin, doxycycline, azlocillin, ceftazidime, amoxicillin, ceftriaxone and aztreonam.

Patients with mild or moderate infections are given by mouth a course of trimethoprim-sulfamethoxazole (TMP/SMX) and ceftazdime. Patients with acute Melioidosis, before the TMP/SMX course, are given first a lengthy course of ceftazidime. The treatment can be administered also intravenously, if the patients have acute septicemia and those with active blood infection, a combination of antibiotics, usually tetrac tetracycline, chloramphenicol and then TMP/SMX. If the disease is not treated early, Melioidosis can provoke bloodstream that is usually fatal. The type of infection and the course of treatment can predict any long-term sequel. Also for patients with more mild illness, are recommended antibiotics like chloramphenicol, doxycycline, sulfisoxazole, or trimethoprim-sulfamethoxazole. For those who suffer severely disease, the conventional treatment regimen is a combination of chloramphenicol, doxycycline and cotrimoxazole. Amoxicillin is a safe alternative to the conventional 4-drug antimicrobial combination for the oral treatment of Melioidosis. It may be of particular value in children, pregnant women, and in infections with Pseudomallei resistant to the potentially toxic conventional regimen, but the optimum dose and duration of therapy need to be established. If sputum cultures remain unchanged and positive for more than 6 months, surgical removal of the lung abscess with lobectomy may intervene.