Fluorescence polarization assay improves the rapid detection of human brucellosis in China

Abstract

Background Brucellosis is an infectious-allergic zoonotic disease caused by bacteria of the genus Brucella. Early diagnosis is the key to preventing, treating, and controlling brucellosis. Fluorescence polarization immunoassay (FPA) is a new immunoassay for relatively rapid and accurate detection of antibodies or antigens based on antigen–antibody interaction. However, there is no report on FPA-based detection of human brucellosis in China. Therefore, this study is to evaluate the value of FPA for the diagnosis of human brucellosis in China. Methods We recruited 320 suspected brucellosis cases who had the clinical symptoms and epidemiological risk factors between January and December, 2019. According to China Guideline for Human Brucellosis Diagnosis, the Rose Bengal test (RBT) was used for the screening test, and the serum agglutination test (SAT) was used as the confirmatory test. Brucellosis was confirmed only if the results of both tests were positive. Additionally, FPA and enzyme linked immune sorbent assay (ELISA) were compared with SAT, and their sensitivity, specificity, coincidence rate and consistency coefficient (Kappa value) as diagnostic tests were analyzed individually and in combination. The optimal cut-off value of FPA was also determined using the receiver operator characteristic (ROC) curve. Results The optimum cut-off value of FPA was determined to be 88.5 millipolarization (mP) units, with a sensitivity of 94.5% and specificity of 100.0%. Additionally, the coincidence rate with the SAT test was 96.6%, and the Kappa value (0.9) showed excellent consistency. The sensitivity and specificity of FPA and ELISA combined were higher at 98.0% and 100.0% respectively. Conclusions When the cut-off value of FPA test is set at 88.5 mP, it has high value for the diagnosis of brucellosis. Additionally, when FPA and ELISA are combined, the sensitivity of diagnosis is significantly improved. Thus, FPA may have potential in the future as a diagnostic method for human brucellosis in China. Graphic abstract

Spatio-Temporal Distribution of Brucellosis in European Terrestrial and Marine Wildlife Species and Its Regional Implications

“…Unfortunately, these tests must be applied without validation due to missing numbers of positive (and negative) sera for the variety of wildlife species to be tested. Competitive ELISA or fluorescent polarization assays (FPA) may be used as they do not depend upon species-specific reagents [ 105 , 106 ]. However, standardization and validation of these diagnostic tests would still be needed [ 107 ].…”

A Label-Based Polymer Nanoparticles Biosensor Combined with Loop-Mediated Isothermal Amplification for Rapid, Sensitive, and Highly Specific Identification of Brucella abortus

“…However, conventional PCR techniques (single PCR, multiplex PCR, and real-time PCR) and immunological tests (ELISA and FPIA) can realize more rapid detection of Brucella spp. than the culture-biotechnical methods, but the demands for PCR thermal cyclers and/or specific antibodies hinder their development in basic laboratories ( Surucuoglu et al, 2009 ; Kang et al, 2011 ; Xu et al, 2020 ; Dong et al, 2021 ). Thus, it is extremely necessary to develop newly diagnostic methods that can meet the above-mentioned requirements.…”

“…Thus, rapid, safe, and sensitive identification techniques are required for the detection of specific-species of Brucella spp. Presently, several rapid detection methods based on immunological tests, including enzyme-linked immunosorbent assay (ELISA) and fluorescence polarization immunoassay (FPIA) have been successfully applied for the serological diagnosis of brucellosis ( Xu et al, 2020 ; Dong et al, 2021 ). Although the sensitivity of the immunological techniques is between 65 and 95%, the low sensitivity of the acute phase, the low specificity of the antibodies, and the need for expensive reagents are major limitations of the methods ( Özdemir et al, 2011 ; Karthik et al, 2014 ).…”

New approach needed for diagnosis of human brucellosis in Morocco

“…The first is used for screening and must be confirmed by another test which is recommended by many international organizations for the diagnosis of human brucellosis. [31,32]. The ELISA is a confirmatory test, simple and easy to perform and interpreted with less time can be used combined with the first test for an easy diagnosis of the disease.…”