Diagnostic accuracy of the Active Melioidosis Detect Plus rapid test for detection of Burkholderia pseudomallei in throat swabs.

OBJECTIVES

Pneumonia is a common presentation of melioidosis. Throat swab culture is a useful investigation but frequently unavailable in endemic settings. This study evaluated the accuracy of the Active Melioidosis Detect Plus rapid diagnostic test (AMD-RDT) on throat swab specimens.

METHODS

In this diagnostic accuracy study in Cambodia and Laos, throat swab specimens from patients with suspected melioidosis underwent AMD-RDT testing, with Burkholderia pseudomallei culture as the reference standard. Diagnostic accuracy parameters were calculated.

RESULTS

Among 1451 throat swab specimens, 38 culture-positive cases and 76 culture-negative controls were tested. AMD-RDT sensitivity was 18.4% (95% confidence intervals [CI] 9.2-33.4) and specificity 100% (95% CI 95.2-100). AMD-RDT positivity occurred only in specimens detected by direct (rather than enrichment alone) culture and was associated with growth abundance (≥2+ [5/5; 100%] vs <2+ [2/33; 6.1%]; P < 0.0001) and culture positivity within 48 hours (7/23; 30.4% vs 0/15; 0%; P = 0.029). In 20/38 (52.6%) cases, the throat swab was the sole positive specimen, and in 9/38 (23.7%) cases B. pseudomallei was identified only after enrichment.

CONCLUSIONS

The AMD-RDT showed inadequate sensitivity on throat swab specimens to support its routine use for this indication. Throat swabs and enrichment culture remain essential components of the diagnostic workup for melioidosis.