Background: Burkholderia pseudomallei is a causative agent of melioidosis. Ceftazidime is the preferred drug of choice for treatment. However, the motility rate is high in endemic areas.
Objective: This study aimed to determine the susceptibility to four different antimicrobial agents and to detect the β-lactamase
genes in B. pseudomallei isolates from patients admitted to Sappasitthiprasong Hospital.
Material and Method: 85 B. pseudomallei isolates from patients admitted to Sappasitthiprasong Hospital between November 2010 and May 2011 were determined for antimicrobial susceptibility by standard disk diffusion and minimum inhibitory
concentration (MIC). Real-time polymerase chain reaction (PCR) was used for the detection of blaPenA and blaOXA in β-
lactamase genes.
Results: Almost all of the clinical isolates of B. pseudomallei were susceptible to ceftazidime and imipenem. Cefatzidime MIC
was <1-16 μg/ml and imipenem MIC was <1-4 μg/ml. The real-time PCR revealed that more than 90% of B. pseudomallei
isolates carried blaPenA and blaOXA.
Conclusion: Although the clinical isolates of B. pseudomallei were susceptible to ceftazidime and imipenem, this study
showed B. pseudomallei had a gene that produced beta-lactamase enzyme and may be poorly effective in the use of betalactam drugs.

Keywords: Burkholderia pseudomallei, Melioidosis, Ceftazidime, β-lactamase, blaPenA