Evaluation of an automated molecular diagnostic instrument for direct detection of Burkholderia pseudomallei from clinical specimens

<b>Background.</b> Melioidosis is a potentially life-threatening infectious disease. The diagnosis of melioidosis is time-critical due to the organism's intrinsic antimicrobial resistance and requirement for directed therapy.<b>Aim.</b> To assess the ability of an automated molecular diagnostic instrument to detect <i>Burkholderia pseudomallei</i> directly from clinical samples.<b>Methods.</b> Urine, sputum, swabs and Ashdown's (ASH) broth were spiked with known concentrations of <i>B. pseudomallei</i> and analysed using an automated PCR platform (Panther^® Fusion; Hologic) targeting the type III Secretion System (TTS-1) gene. In addition, clinical specimens from patients with confirmed melioidosis were also evaluated.<b>Results.</b> Urine was the clinical sample that demonstrated the lowest limit of detection (LOD), 1.8×10² c.f.u. ml^-1. Compared with dry swabs (LOD: 1.0×10³ c.f.u. ml^-1), Amies agar swabs were inferior (LOD: >3.3×10⁴ c.f.u. ml^-1). Inoculation of dry swabs into ASH, with an abbreviated incubation period, did not improve detection. All culture-positive sputum and urine samples from patients with confirmed melioidosis were detected by the PCR method.<b>Conclusion.</b> This study demonstrates the ability of the Panther^® to directly detect <i>B. pseudomallei</i> across a range of clinical sample types and estimates the minimum bacterial concentration required for diagnostic detection. The described methodology holds promise for expediting diagnosis and, in turn, enhancing patient outcomes.