Current antimicrobial susceptibility of first-episode melioidosis Burkholderia pseudomallei isolates from the Northern Territory, Australia.

Burkholderia pseudomallei is a saprophytic Gram-negative bacterium responsible for the tropical infectious disease melioidosis. Melioidosis is endemic to northern Australia and Southeast Asia. In this study, 234 isolates of B. pseudomallei obtained from the first positive clinical specimen from 234 consecutive patients diagnosed with melioidosis between October 2009 and September 2012 were reviewed. All isolates were susceptible to meropenem and ceftazidime. In total, 226 isolates (96.6%) were susceptible to doxycycline and 232 (99.1%) were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX; co-trimoxazole). Primary resistance of B. pseudomallei to ceftazidime and/or meropenem is exceedingly rare and clinicians can be confident in the current treatment guidelines for melioidosis. Whether the very low rates of TMP/SMX resistance seen in Australia reflect the global situation requires further studies using Etest, especially to clarify the rate of resistance in Thailand.