Definition
Melioidosis is an infectious disease caused by Burkholderia pseudomallei (also known as Pseudomonas pseudomallei ), a Gram-negative bacillus common in tropical regions, present in soil and water. This bacterium is endemic, in particular, in South-East Asia (from Pakistan to the Philippines), in the southern provinces of China, in Oceania and in central, western and eastern Africa.
The pathogen responsible for melioidosis proliferates above all in moist soils (eg rice fields).
The man can contract the infection following the contamination with earth or mud of small skin wounds, abrasions and burns.
Other ways of transmission are ingestion, inhalation or aspiration of contaminated water. The infection is not transmitted, however, directly from domestic and wild animals, nor from other infected men. In endemic areas, melioidosis can easily affect AIDS patients.
Most common symptoms and signs *
- Anorexia
- Skin abscess
- Asthenia
- Bacteremia
- Cyanosis
- Colic
- Temporal and spatial disorientation
- Dyspnoea
- Chest pain
- Pain in the upper part of the abdomen
- Articolar pains
- Muscle pains
- hemoptysis
- Hepatomegaly
- Pharyngitis
- Flatulence
- Hypotension
- Headache
- Meningitis
- Multiple pulmonary nodules
- Pustules
- rales
- splenomegaly
- tachypnoea
- Cough
- Pleural effusion
Further indications
Melioidosis can present with very variable clinical manifestations, ranging from inapparent forms (asymptomatic) to respiratory tract infections (pneumonia), up to acute disseminated septicemic melioidosis (often fatal).
Acute lung infection is the most common form. Onset may be sudden or gradual, with headache, anorexia, chest pain, generalized myalgia and fever (generally above 39 ° C). Cough, tachypnea and rales are characteristic manifestations; sputum can be streaked with blood. X-ray examination of the chest may show irregular nodular lesions, thin-walled cysts and pleural effusion.
Chronic melioidosis may also occur, with characters of a suppurative infection, located in the lungs, skin, lymph nodes or bones. These involve the formation of bone lesions (secondary to osteomyelitis) and abscesses in the various districts affected.
Septicemic melioidosis, on the other hand, begins suddenly, with septic shock and involvement of multiple organs. It manifests as high fever, disorientation, dyspnoea, severe headache, pharyngitis, high abdominal colic, diarrhea, pustular skin lesions, hypotension, tachypnea and cyanosis. Sometimes, signs of arthritis or meningitis appear.
The diagnosis of melioidosis is formulated with the analysis of cultures for the identification of pathogens and with serological investigations, such as haemagglutination (IHA), direct immunofluorescence, immunoassay linked to the enzyme (ELISA) or the test of fixation of the complement. The liver and spleen can be palpable. Liver function tests, AST and bilirubin are often impaired.
The therapy is based on the administration of antibiotics, such as ceftazidime or the combination of trimethoprim / sulfamethoxazole.
