Quantitative recovery of Burkholderia pseudomallei from soil in

Melioidosis is common in north-eastern Thailand, but is reported rarely from the adjacent areas of central Thailand, although rice farming is common to both regions. Quantitative soil cultures for Burkhulderia pseu-a%malL & were therefore prepared on 12 rice farms in both regons. B. psezrdmallei was isolated from a simi-lar proportion of rice tields in the central re ‘on (6112 and in the north-east (7112). Within the culture-positive sites, the number of B. ri f ’ pseudonurl colony- orming units (cfu) per mL of soiywater super-natant was significantly higher in the north-cast (median 230 cfuiml; range 1-17 000) than in the central re-gion (median 10 cfu/mL; range l-600). As bacterial counts in the soil are probably related to the risk of developing melioidosis, differences in exposure to B. pseudomallei probably contribute to the considerable differences in the incidence of this disease between these 2 adjacent regions