Comparative in vitro susceptibility of burkholderia pseudomallei to doripenem, ertapenem, tigecycline and moxifloxacin

Abstract

<h3>Background</h3> Melioidosis continues to present therapeutic challenges in endemic areas, including tropical Australia. A number of clinical issues have prompted the search for alternative antimicrobial therapies. These include stability in 24 hour infusion pumps, broad spectrum coverage in the empiric treatment of community acquired pneumonia, cost, the need for effective oral agents and rare reports of emerging resistance. <h3>Objectives</h3> To examine the <i>in vitro</i> susceptibility of <i>Burkholderia pseudomallei</i> to four new antimicrobial agents, including moxi-floxacin, tigecycline, ertapenem and doripenem. <h3>Methods</h3> A total of 100 clinical isolates were tested using Etest and disc diffusion. As there are no interpretative standards for these antimicrobials, MIC₉₀ values were compared to those for merope-nem. MIC values were correlated with zone of inhibition diameters. <h3>Results</h3> The MIC values for doripenem were broadly similar to those for meropenem, demonstrating a MIC₉₀ of 1.5 μg/mL (MIC range 0.38–4μg/mL). There was good correlation (<i>r</i>=–0.71; <i>p</i> < 0.001) between the MIC and disc diffusion for doripenem. Ertapenem, tigecycline and moxifloxacin had limited in vitro activity in this study, although no interpretative criteria exist for these agents. <h3>Conclusions</h3> Further <i>in vitro</i>, animal and clinical studies are suggested to validate the efficacy of doripenem in the management of melioidosis.