Abstract. The predictors of severe disease or death were determined for 85 melioidosis patients in Kuala Lumpur, Malaysia. Most of the patients were male, 40 years old, and diabetic. Severe disease or death occurred in 28 (32.9%) cases. Lower lymphocyte counts and positive blood cultures were significant independent predictors of severe disease, but age, presentations with pneumonia, inappropriate empirical antibiotics, or flagellin types of the infecting isolates were not. Knowledge of local predictors of severe disease is useful for clinical management.Melioidosis is endemic in southeast Asia and northern Australia. Clinical manifestations are diverse, with the most severe forms often leading to death. Mortality rates vary widely between settings (for example, between Australian [19%] and Thai [50%] patients).1 This may be because of differences in patient populations, strain virulence, environmental factors, and healthcare facilities. It is not certain whether variations within virulence coding genes influence severity of melioidosis. The flagellin protein in Burkholderia pseudomallei is involved in mobility, invasion, and virulence.2 The flagellin (fliC) gene has been used to type B. pseudomallei by polymerase chain reaction (PCR) -restriction fragment-length polymorphism (RFLP).3 However, flagellin types have yet to be correlated with clinical presentation. It is important to predict which patients are most at risk of severe disease to institute earlier interventions, such as appropriate antibiotics and intensive care unit (ICU) admission. Therefore, the objectives of this study were to determine clinical and laboratory predictors of severe melioidosis, including flagellin types.This retrospective study reviewed clinical and laboratory data of patients with a first presentation of culture-positive melioidosis from any site from August of 1988 to June of 2010 at a teaching hospital in Kuala Lumpur, Malaysia. A standard data collection form was used. Severe disease was defined as death or requirement of ICU admission, ventilation, or inotropic support. Appropriate empirical antibiotics were defined as treatment started before culture results were available using any of the antibiotics recommended for melioidosis treatment, which are ceftazidime, imipenem, meropenem, coamoxiclav, doxycycline, chloramphenicol, and cotrimoxazole. 4 Approval was obtained from the hospital's Medical Ethics Committee (reference no. 733.8).Flagellin gene typing was carried out on available stocked isolates of B. pseudomallei as described in an earlier study, 3 which included isolates of 24 patients included in this study. Bacterial isolates were recovered from stocks on MuellerHinton or blood agar at 37 C for 24-48 hours. Colonies were suspended in 500 μL sterile distilled water, heated at 100 C for 30 minutes, cooled down in ice, briefly vortexed, and centrifuged at 12,000 rpm for 1 minute. The supernatant was used as the DNA template for amplification of the fliC gene using the primer pairs BC6E (5 -ACCAACAGCCTGCAGCGTATC-3 ) and ...