BACKGROUND: The environmental bacterium Burkholderia pseudomallei causes the 
infectious disease melioidosis with a high case-fatality rate in tropical and 
subtropical regions. Direct pathogen detection can be difficult, and therefore 
an indirect serological test which might aid early diagnosis is desirable. 
However, current tests for antibodies against B. pseudomallei, including the 
reference indirect haemagglutination assay (IHA), lack sensitivity, specificity 
and standardization. Consequently, serological tests currently do not play a 
role in the diagnosis of melioidosis in endemic areas. Recently, a number of 
promising diagnostic antigens have been identified, but a standardized, 
easy-to-perform clinical laboratory test for sensitive multiplex detection of 
antibodies against B. pseudomallei is still lacking.
METHODS AND PRINCIPAL FINDINGS: In this study, we developed and validated a 
protein microarray which can be used in a standard 96-well format. Our array 
contains 20 recombinant and purified B. pseudomallei proteins, previously 
identified as serodiagnostic candidates in melioidosis. In total, we analyzed 
196 sera and plasmas from melioidosis patients from northeast Thailand and 210 
negative controls from melioidosis-endemic and non-endemic regions. Our protein 
array clearly discriminated between sera from melioidosis patients and controls 
with a specificity of 97%. Importantly, the array showed a higher sensitivity 
than did the IHA in melioidosis patients upon admission (cut-off IHA titer 
≥1:160: IHA 57.3%, protein array: 86.7%; p = 0.0001). Testing of sera from 
single patients at 0, 12 and 52 weeks post-admission revealed that protein 
antigens induce either a short- or long-term antibody response.
CONCLUSIONS: Our protein array provides a standardized, rapid, easy-to-perform 
test for the detection of B. pseudomallei-specific antibody patterns. Thus, this 
system has the potential to improve the serodiagnosis of melioidosis in clinical 
settings. Moreover, our high-throughput assay might be useful for the detection 
of anti-B. pseudomallei antibodies in epidemiological studies. Further studies 
are needed to elucidate the clinical and diagnostic significance of the 
different antibody kinetics observed during melioidosis.