What is the Role of Lateral Flow Immunoassay for the Diagnosis of Melioidosis?

Bart J Currie; Celeste Woerle; Mark Mayo; Ella M Meumann; Robert W Baird

doi:10.1093/ofid/ofac149

What is the Role of Lateral Flow Immunoassay for the Diagnosis of Melioidosis?

Open Forum Infect Dis. 2022 Mar 21;9(5):ofac149. doi: 10.1093/ofid/ofac149. eCollection 2022 May.

Authors

Bart J Currie^{1

2}, Celeste Woerle¹, Mark Mayo¹, Ella M Meumann^{1

2}, Robert W Baird²

Affiliations

¹ Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
² Departments of Infectious Diseases and Pathology and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia.

Abstract

Background: Culture of Burkholderia pseudomallei remains the gold standard for diagnosis of melioidosis but is not possible in many resource-limited settings where melioidosis is endemic. Direct identification of B. pseudomallei antigen in clinical samples has been developed using a lateral flow immunoassay (LFA) targeting B. pseudomallei capsular polysaccharide.

Methods: We summarized the findings from the 8 studies to date of the Active Melioidosis Detect (AMD) LFA and compared these with our results from 232 patients with culture-confirmed melioidosis. We have also optimized the methodology for testing different clinical samples.

Results: Sensitivity and specificity for different samples were broadly similar in our study to those published from Thailand, India, Laos, and Malaysia. One hundred thirty of 232 (56%) of our melioidosis patients were positive on 1 or more AMD tests: 27% for serum (rising to 39% in those with bacteremic melioidosis and 68% in those with septic shock), 63% for urine (72% in bacteremic melioidosis and 90% in septic shock), 85% in sputum that was culture positive, and 83% in pus that was culture positive. Heating sputum and pus samples increased sensitivity. Faint false-positive urine bands seen on earlier AMD versions were not seen when retested using the most recent version, AMD-Plus.

Conclusions: While the sensitivity of melioidosis LFA is low overall for blood samples, there is potential for use as a rapid diagnostic: testing serum and urine from those with severe sepsis who may have melioidosis and testing sputum and pus samples from clinically relevant scenarios. Prospective studies of patients with sepsis and other clinical presentations resembling melioidosis are required to ascertain if the specificity of AMD-PLUS is adequate to enable diagnosis of melioidosis with a high positive predictive value.

Keywords: Burkholderia pseudomallei; diagnostics; lateral flow immunoassay; melioidosis; rapid antigen test.