Development and evaluation of an up-converting phosphor technology-based lateral flow assay for rapid and quantitative detection of Coxiella burnetii phase I strains

• Main Authors: Pingping Zhang, Jun Jiao, Yong Zhao, Mengjiao Fu, Jin Wang, Yajun Song, Dongsheng Zhou, Yongqiang Wang, Bohai Wen, Ruifu Yang, Xiaolu Xiong
• Format: Article
• Language: English
• Published: BMC 2020-08-01
• Series: BMC Microbiology
• Subjects: Coxiella burnetii; Q fever; Lipopolysaccharide; Up-converting phosphor technology-based lateral flow; Monoclonal antibody
• Online Access: http://link.springer.com/article/10.1186/s12866-020-01934-0

Abstract Background Coxiella burnetii is an obligate intracellular Gram-negative bacterium that causes a zoonotic disease commonly called Q fever globally. In this study, an up-converting phosphor technology-based lateral flow (UPT-LF) assay was established for the rapid and specific detection of phase I strains of C. burnetii. Results Specific monoclonal antibodies (10B5 and 10G7) against C. burnetii phase I strains were prepared and selected for use in the UPT-LF assay by the double-antibody-sandwich method. The detection sensitivity of the Coxiella-UPT-LF was 5 × 104 GE/ml for a purified C. burnetii phase I strain and 10 ng/ml for LPS of C. burnetii Nine Mile phase I (NMI). Good linearity was observed for C. burnetii phase I and NMI LPS quantification (R2 ≥ 0.989). The UPT-LF assay also exhibited a high specificity to C. burnetii, without false-positive results even at 108 GE/ml of non-specific bacteria, and good inclusivity for detecting different phase I strains of C. burnetii. Moreover, the performance of the Coxiella-UPT-LF assay was further confirmed using experimentally and naturally infected samples. Conclusions Our results indicate that Coxiella-UPT-LF is a sensitive and reliable method for rapid screening of C. burnetii, suitable for on-site detection in the field.