Effects of soil pH, temperature and water content on the growth of Burkholderia pseudomallei

Optimum conditions were determined for the growth of Burkholderia pseudomallei in natural soils or waters. It grows better in paddy soil, crop-covered and fallow field than in fresh and salty water. Although the optimal temperature and pH for the growth were 37 or 42 degreesC, and 6.5 or 7.5 in an environmental-mimicking soil medium, this bacterium can still grow at 4 degreesC, which was suggested to be related with the occurrence of melioidosis in some cold areas. In soil media with water content < 15. B. pseudo-mallei did not grow until 60 d of incubation, suggesting that water contents of soils in which it dwelled would be one important factor in determining the growth rate.