title: Development of a prototype lateral flow immunoassay (LFI) for the rapid diagnosis of melioidosis.
abstract: Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. Isolation of B. pseudomallei from clinical samples is the "gold standard" for the diagnosis of melioidosis; results can take 3-7 days to produce. Alternatively, antibody-based tests have low specificity due to a high percentage of seropositive individuals in endemic areas. There is a clear need to develop a rapid point-of-care antigen detection assay for the diagnosis of melioidosis. Previously, we employed In vivo Microbial Antigen Discovery (InMAD) to identify potential B. pseudomallei diagnostic biomarkers. The B. pseudomallei capsular polysaccharide (CPS) and numerous protein antigens were identified as potential candidates. Here, we describe the development of a diagnostic immunoassay based on the detection of CPS. Following production of a CPS-specific monoclonal antibody (mAb), an antigen-capture immunoassay was developed to determine the concentration of CPS within a panel of melioidosis patient serum and urine samples. The same mAb was used to produce a prototype Active Melioidosis Detect Lateral Flow Immunoassay (AMD LFI); the limit of detection of the LFI for CPS is comparable to the antigen-capture immunoassay (∼0.2 ng/ml). The analytical reactivity (inclusivity) of the AMD LFI was 98.7% (76/77) when tested against a large panel of B. pseudomallei isolates. Analytical specificity (cross-reactivity) testing determined that 97.2% of B. pseudomallei near neighbor species (35/36) were not reactive. The non-reactive B. pseudomallei strain and the reactive near neighbor strain can be explained through genetic sequence analysis. Importantly, we show the AMD LFI is capable of detecting CPS in a variety of patient samples. The LFI is currently being evaluated in Thailand and Australia; the focus is to optimize and validate testing procedures on melioidosis patient samples prior to initiation of a large, multisite pre-clinical evaluation.
authors.affiliation: InBios International, Inc., Seattle, Washington, United States of America.
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Houghton
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America.
authors.forename: Dana E
authors.initials: DE
authors.lastname: Reed
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hubbard
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dillon
authors.affiliation: InBios International, Inc., Seattle, Washington, United States of America.
authors.forename: Hongjing
authors.initials: H
authors.lastname: Chen
authors.affiliation: Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
authors.affiliation: Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Mayo
authors.affiliation: Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
authors.forename: Derek S
authors.initials: DS
authors.lastname: Sarovich
authors.affiliation: Menzies School of Health Research and Northern Territory Clinical School, Royal Darwin Hospital, Darwin, Northern Territory, Australia.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Theobald
authors.affiliation: Department of Tropical Hygiene, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Direk
authors.initials: D
authors.lastname: Limmathurotsakul
authors.affiliation: Department of Clinical Pathology, Sappasithiprasong Hospital, Ubon Ratchathani, Thailand.
authors.forename: Gumphol
authors.initials: G
authors.lastname: Wongsuvan
authors.affiliation: Department of Microbiology and Immunology, and Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Narisara
authors.initials: N
authors.lastname: Chantratita
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand, and Department of Medicine, Cambridge University, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
authors.affiliation: Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Hoffmaster
authors.affiliation: Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Brea
authors.initials: B
authors.lastname: Duval
authors.affiliation: Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Brett
authors.affiliation: Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, United States of America.
authors.forename: Mary N
authors.initials: MN
authors.lastname: Burtnick
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, United States of America.
authors.forename: David P
authors.initials: DP
authors.lastname: Aucoin
mesh_terms: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial / Q000276:immunology*; D001315:Australia; D016957:Burkholderia pseudomallei / Q000276:immunology / Q000302:isolation & purification*; D002846:Chromatography, Affinity / Q000379:methods*; D006801:Humans; D008554:Melioidosis / Q000175:diagnosis*; D019095:Point-of-Care Systems; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012680:Sensitivity and Specificity; D013785:Thailand
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial