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. 2020 Aug 12;20(1):251.
doi: 10.1186/s12866-020-01934-0.

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

Pingping Zhang  1   2 , Jun Jiao  1   2 , Yong Zhao  1   2 , Mengjiao Fu  1   2 , Jin Wang  1   2 , Yajun Song  1   2 , Dongsheng Zhou  1   2 , Yongqiang Wang  3 , Bohai Wen  1   2 , Ruifu Yang  4   5 , Xiaolu Xiong  6   7
Affiliations

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

Pingping Zhang et al. BMC Microbiol. .

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.

Keywords: Coxiella burnetii; Lipopolysaccharide; Monoclonal antibody; Q fever; Up-converting phosphor technology-based lateral flow.

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Conflict of interest statement

Author Dongsheng Zhou is an Associate Editor of this journal. The authors have no conflict of interest to declare.

Figures

Fig. 1
Fig. 1
Assessment of UPT-LF strips fabricated using different antibodies. Nitrocellulose membranes and conjugation pads both with various antibodies were paired randomly in the fabrications of the strips, and each strip was used for the detection of C. burnetii Xinqiao strain at three different concentrations with primary sample treating buffer and different labelling conditions between UCPs and antibodies. The letter “P” before the name of the antibodies means that the antibodies were on the conjugate pad, while the letter “M” means they were on the nitrocellulose membrane
Fig. 2
Fig. 2
The detection limit, sensitivity, and precision of Coxiella-UPT-LF. a Photograph of a UPT-LF strip. b Photograph of the UPT biosensor. c Illustrations of the UPT assay for the detection of C. burnetii Xinqiao strain. Peaks on the left are signals for the control bands, and peaks on the right are for test bands. d LPS immunoblot of C. burnetii NMI and NMII. LPS of C. burnetii NMI and NMII was separated by SDS-PAGE, silver-stained, and probed with PI LPS-specific mAbs (10B5 and 10G7). e Standard curve for the quantification of C. burnetii Xinqiao strain by Coxiella-UPT-LF, with the logarithm of the difference between the T/C ratio and the cut-off value on the horizontal axis and the logarithm of the concentration (GE/ml) on the vertical axis. Data were expressed as mean ± SD, n = 3. f Standard curve for the quantification of NMI LPS by Coxiella-UPT-LF, with the logarithm of the difference between the T/C ratio and the cut-off value on the horizontal axis and the logarithm of the concentration (GE/ml) on the vertical axis. Data were expressed as mean ± SD, n = 3
Fig. 3
Fig. 3
Evaluation of the specificity of Coxiella-UPT-LF. Except slight cross-reaction with V. cholerae O139, Coxiella-UPT-LF showed high specificity, without false-positive results for non-specific bacterial species. Data were expressed as mean ± SD, n = 3
Fig. 4
Fig. 4
Inclusivity of Coxiella-UPT-LF for C. burnetii. a The inclusivity of Coxiella-UPT-LF for the detection of C. burnetii strains cultured in YS. Data were expressed as mean ± SD, n = 3. b The inclusivity of Coxiella-UPT-LF for the detection of C. burnetii strains cultured in ACCM-2 medium. Data were expressed as mean ± SD, n = 3. c LPS immunoblot of C. burnetii PI strains isolated in China. LPS of C. burnetii Xinqiao, Yaan, and H-11 strains was separated by SDS-PAGE, silver-stained, and probed with PI LPS-specific mAbs (10B5 and 10G7)
Fig. 5
Fig. 5
Detection results for Coxiella-UPT-LF of different C. burnetii strains in infected mice and ticks. a Detection results for Coxiella-UPT-LF of C. burnetii strains in organs from infected mice and control mice. Data were expressed as mean ± SD, n = 3. b Detection results for Coxiella-UPT-LF of C. burnetii strains in tick samples. Data were expressed as mean with 95% CI
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References

    1. Amano K, Williams JC. Chemical and immunological characterization of lipopolysaccharides from phase I and phase II Coxiella burnetii. J Bacteriol. 1984;160(3):994–1002. doi: 10.1128/JB.160.3.994-1002.1984. - DOI - PMC - PubMed
    1. Hackstadt T, Peacock MG, Hitchcock PJ, Cole RL. Lipopolysaccharide variation in Coxiella burnetti: intrastrain heterogeneity in structure and antigenicity. Infect Immun. 1985;48(2):359–365. doi: 10.1128/IAI.48.2.359-365.1985. - DOI - PMC - PubMed
    1. Beare PA, Jeffrey BM, Long CM, Martens CM, Heinzen RA. Genetic mechanisms of Coxiella burnetii lipopolysaccharide phase variation. PLoS Pathog. 2018;14(3):e1006922. - PMC - PubMed
    1. Raoult D, Marrie T, Mege J. Natural history and pathophysiology of Q fever. Lancet Infect Dis. 2005;5(4):219–226. doi: 10.1016/S1473-3099(05)70052-9. - DOI - PubMed
    1. Bae M, Jin CE, Park JH, Kim MJ, Chong YP, Lee SO, et al. Diagnostic usefulness of molecular detection of Coxiella burnetii from blood of patients with suspected acute Q fever. Medicine. 2019;98(23):e15724. doi: 10.1097/MD.0000000000015724. - DOI - PMC - PubMed

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