6. ª×èÍàÃ×èͧ:
                            EPIDEMIOLOGY OF ARABINOSE ASSIMILATION IN BURKHOLDERIA

PSEUDOMALLEI ISOLATED FROM PATIENTS AND SOIL IN THAILAND

ª×èͼÙéÇÔ¨ÑÂ:
                           Suwanna Trakulsomboon1,Varaporn Vuddhakul2,Prasit Tharavichitkul3,Narisorn Na-

Gnam4, Yupin Suputtamonkol1 and Visanu Thamlikitkul1

                         

                           1Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University,

  Bangkok, Thailand;

                          2Department of Microbiology, Faculty of Science, Prince of Songkla University,
                           Songkhla, Thailand; 3Department of Microbiology, Faculty of Medicine, Chiang Mai
                           University, Chiang Mai, Thailand; 4Faculty of Veterinary Medicine, Khon Kaen

University, Khon Kaen, Thailand

   µÕ¾ÔÁ¾ì: Southeast Asian J. Trop Med Public Health. 1999. 30 (4): 756-759.
Abstract.
                       urkholderia pseudomallei is an environmental saprophyte that has been isolated widely
from soil in Southeast Asia and the relationship between environmental contamination and
clinical melioidosis has been established. It has been shown that the arabinose assimilation
property of B.pseudomallei is probably one of the determinants indicating virulence of this
organism. Therefore, the distribution of arabinose assimilation biotypes of B. pseudomallei
collected from four geographic regions of Thailand was studied in order to determine an
association between arabinose assimilation of B. pseudomallei and the uneven distribution of
melioidosis found among these four areas. A total of 830 isolates of B.pseudomalle (412 patient
isolates and 418 soil isolates) collected from the patients and soil in four regions of Thailand in
1997 were tested for an ability to grow on a minimal agar medium supplemented with L-
arabinose. All patient isolates except one could not utilise arabinose (Ara-). For 418 soil isolates,
232 (55.5%) isolates were identified as Ara- type. They comprised 180 (62.5%), 36 (46.8%), 6
(35.3%) and 10 (27.8%) isolates derived from northeastern, southern, northern and central regions
respectively. The ratios of Ara- to Ara+ were 1.7, 0.9, 0.5 and 0.4 among isolates collected from
northeastern, southern, northern and central regions respectively. The prevalence of Ara- in soil
isolates in northeast is significantly higher than those in other regions. This observation suggests
that in addition to the presence of B. pseudomallei in soil which is one of the factors contributing
to a burden of melioidosis in northeastern Thailand, the distribution of more virulent biotype
(Ara-) soil isolates is a factor contributing to a high prevalence of melioidosis in northeastern

Thailand as well.