Ribotyping of Burkholderia pseudomallei from clinical and soil isolates inThailand

Burkholderia pseudomallei is a soil saprophyte that causes melioidosis in h umans and animals. Restriction fragment length polymorphism of the ribosoma l DNA regions (ribotyping) were analyzed in 577 isolates comprising 371 cli nical and 206 soil isolates collected throughout Thailand in 1997. A total of 77 distinct ribotype patterns consisting of 2-9 bands with sizes ranging from 2.8 to > 23 kb were found. Twelve major ribotypes were identified of which types 3, 8 and 23 were commonly found (278/577, 48.2%) in both clinic al (217/371, 58.5%) and environmental isolates (61/206, 29.6%). Three uniqu e environmental types were found whereas a unique clinical type was not obs erved. Even though ribotypes show high heterogeneity in the rDNA region, th e unique environmental patterns were clearly different from the clinical pa tterns as clearly seen by UPGMA dendrogram. Moreover, the three major types (types 3, 8 and 23) were discovered in nearly half of B. pseudomallei isol ates. Subtyping of these major ribotypes in correlation with clinical profi les may help researchers to identify the virulence factor of the organism. (C) 2001 Elsevier Science B.V. All rights reserved.