Antimicrobial Susceptibility and Genetic Characterisation ofBurkholderia pseudomalleiIsolated from Malaysian Patients

Abstract

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics. Ceftazidime (CAZ), the syntheticβ-lactam, is normally used as the first-line antibiotic therapy for treatment of melioidosis. However, acquired CAZ resistance can developin vivoduring treatment with CAZ, leading to mortality if therapy is not switched to a different antibiotic(s) in a timely manner. In this study, susceptibilities of 81B. pseudomalleiisolates to nine different antimicrobial agents were determined using the disk diffusion method, broth microdilution test and Etest. Highest percentage of susceptibility was demonstrated to CAZ, amoxicillin/clavulanic acid, meropenem, imipenem, and trimethoprim/sulfamethoxazole. Although these drugs demonstrated the highest percentage of susceptibility inB. pseudomallei, the overall results underline the importance of the emergence of resistance in this organism. PCR results showed that, of the 81B. pseudomallei, six multidrug resistant (MDR) isolates carriedbpeB,amrB, andBPSS1119andpenAgenes. Genotyping of the isolates using random amplified polymorphic DNA analysis showed six different PCR fingerprinting patterns generated from the six MDR isolates clusters (A) and eight PCR fingerprinting patterns generated for the remaining 75 non-MDR isolates clusters (B).