Abstract
Burkholderia pseudomallei is a causative agent of melioidosis. Ceftazidime is a drug of choice
for treatment of this infection but the mortality rate is high in some endemic areas. This study investigates
the effectiveness of antibiotics by an in vitro antimicrobial susceptibility test. A total of
1,340 B. pseudomallei samples were isolated from patients admitted to Sappasitthiprasong Hospital,
Sisaket Hospital, and Amnatcharoen Hospital between January 2013 and February 2015. Antimicrobial
susceptibility of B. pseudomallei were evaluated by the standard disk diffusion test and to determine
minimum inhibitory concentration (MIC). Ceftazidime, imipenem, trimethoprim+sulfamethoxazole,
and ciprofloxacin were used as antimicrobial agents for the standard disk diffusion test, and MIC was
determined for ceftazidime, imipenem, and trimethoprim+sulfamethoxazole. Bacteria strains were
randomly selected for conventional polymerase chain reaction (PCR) followed by gel electrophoresis
analysis for penA and oxa gene.
Results demonstrated that all the antimicrobial agents were effective against B. pseudomallei.
Trimethoprim+sulfamethoxazole was 100% effective, and ceftazidime and imipenem were 98.36%
and 99.10% effective respectively. Ceftazidime MIC was 0.25 to ≥32 mg/ml and imipenem MIC was ≤0.5
to 16 mg/ml. It was found that 1.27% of B. pseudomallei was resistant to ceftazidime and 0.37% was
resistant to imipenem. All random samples found oxa gene but not penA gene.
It was concluded that all antimicrobial agents tested effective. Ceftazidime and imipenem were
bactericidal drugs of choice for melioidosis treatment. The bacteriostatic agent for B. pseudomallei
was trimethoprim+sulfamethoxazole. Although, the activity of the antimicrobial agents was effective
in vitro, early diagnostic and prompt clinical treatment to which drugs be administered intravenously
still urgently needed.
