Melioidosis

Melioidosis is an endemic infection caused by Burkholderia pseudomallei, endemic in Southeast Asia and northern Australia. Humans are infected through broken skin contacting contaminated water/soil. It has complex manifestations: acute septicemic forms with multiple purulent lesions; chronic forms resembling cavitary pulmonary TB. The course is usually severe; without prompt treatment, fatality is very high.

Common Symptoms

Chills; hepatosplenomegaly; Yue Han; diarrhea; pustule; myalgia; hemoptysis; abdominal pain; rales

Causes and Pathogenesis

B. pseudomallei is a saprophytic Gram-negative aerobic coccobacillus resistant to environmental factors, found in soil and surface water; humans are infected by contact, respiratory/digestive routes, or insect bites; no human-to-human transmission. Whitmore and Krishnaswami first identified it in Rangoon in 1912; named Pseudomonas pseudomallei, then Whitmore's bacillus, then Pseudomonas pseudomallei, now Burkholderia pseudomallei (1993). It is a short straight Gram-negative coccobacillus 1-2 × 0.5-0.8 µm, mostly single, with ≥3 polar flagella (motile), bipolar staining, no capsule/spores; a surrounding unstained halo (pseudocapsule) appears on impression smears. Aerobic, grows well on ordinary media with glycerol; smooth colonies at 24 h become rough/rugae at 48-72 h with a musty odor; ferments glucose/lactose/maltose/mannose/ribose/sucrose (acid without gas) but not xylose. Antigens: specific heat-stable polysaccharide and shared heat-labile protein (cross-reacting with glanders), plus flagellar antigen; serotypes I (Asia, both antigens) and II (Australia/Africa, heat-stable only). It survives 27 days in feces, 17 days in urine, 8 days in carcasses, >1 year in water/soil, 28-44 days in tap water; Guangzhou observations show 726-day survival in 40% water soil; killed by 56°C/10 min and common disinfectants (but not phenol/cresol; 5% chloramine-T is preferred).

Treatment

Drug therapy, symptomatic treatment, supportive therapy

Preventive Measures

No vaccine exists. Survey endemic areas (Guangdong, Guangxi, Hainan) by testing stagnant water, soil, and suspected pigs/cattle/sheep; terminal-disinfect after typhoons/heavy rains; quarantine livestock to prevent spread to non-endemic areas; include meat inspection; personal protection against contaminated water/soil; thoroughly disinfect patient/animal excreta and purulent discharge; disinfect skin after contact; medically observe suspected contacts for 2 weeks; strictly quarantine imported animals; mallein eye-drop tests for equid quarantine.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.