Antibiotic susceptibility of Burkholderia pseudomallei from tropical northern Australia and implications for therapy of melioidosis

From a prospective melioidosis study commencing in 1989 at Royal Darwin Hos pital, 170 initial isolates of Burkholderia pseudomallei were available for susceptibility testing. Of these 163 (96%) were susceptible to meropenem/i mipenem, ceftazidime, trimethoprim-sulphamethoxazole (SMX/TMP) and doxycycl ine. Seven (4%) showed primary resistance; three had low-level resistance t o SMX/TMP, one to ceftriaxone and amoxycillin/clavulanate (AMOX/CA) and thr ee to doxycycline. Of 167 patients who survived their initial presentation, seven (4%,) had culture positive infections which persisted for greater th an 3 months after start of therapy. All ultimately cleared carriage of B. p seudomallei though three required changing to SMX/TMP after development of doxycycline resistance. Nineteen (11%) of the initial survivors clinically relapsed and 17 of these had repeat isolates available for testing. Four of these had acquired resistance: one to doxycyline, one to AMOX/CA and cefta zidime, one to SMX/TMP and one to both SMX/TMP and doxycycline. Molecular t yping using randomly amplified polymorphic DNA and pulsed-held gel electrop horesis showed all but one relapse isolate to be the same as the original s train. These data an similar to published data from Thailand. As melioidosi s has a high mortality (21% in this series) these results emphasize the nee d for prolonged eradication therapy and regular clinical and microbiologica l monitoring so that the emergence of resistance can be detected early and appropriate treatment modifications made. (C) 2001 Elsevier Science B.V, an d international Society of Chemotherapy. All rights reserved.