Burkholderia pseudomallei

Burkholderia pseudomallei is a Gram-negative, aerobic, motile, rod-shaped soil bacterium, once classified as Pseudomonas pseudomallei, that is endemic in tropical and subtropical regions, particularly in Thailand and northern Australia. Cells measure about 2 to 5 micrometres long and 0.4 to 0.8 micrometres across and move with flagella. Although it lives mainly in soil, one study found it survived in distilled water for 16 years, and it resists nutrient shortage, extreme temperature and pH. It causes melioidosis in humans, with a mortality of 20 to 50 percent even with treatment, and also infects livestock such as goats, pigs and sheep; the United States CDC lists it as a Tier 1 select agent. In the laboratory it grows on ordinary media within one to two days and is typically identified by wrinkled colonies with an earthy smell and by intrinsic resistance to colistin and gentamicin, which separates it from the related B. mallei.