Sandwich-Based Immunosensor for Dual-Mode Detection of Pathogenic F17-Positive
Escherichia coli Strains.
Int J Mol Sci 2022;
23:ijms23116028. [PMID:
35682707 PMCID:
PMC9181454 DOI:
10.3390/ijms23116028]
[Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/11/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022] Open
Abstract
Bacterial diseases cause tremendous economic losses due to high morbidity and mortality in livestock animals. F17A protein, the major subunit of F17 fimbriae, is one of the most prevalent and crucial virulence factors among the pathogenic Escherichia coli (E. coli) isolated from diarrheic and septicemic animals of various species. Purification and detection of this protein is regarded as an interesting field of investigation due to its important role as a therapeutic target, such as vaccines, and as a diagnostic tool. In this context, polyclonal rabbit antibodies recognizing F17A protein (anti−F17A antibody) were developed and used for its detection. In fact, sandwich biosensor using anti−F17A/gold nanoparticles conjugates as capture probe and anti−F17A antibody labelled with horseradish peroxidase as signal amplification probe was developed for electrochemical and fluorescent detection of purified F17A protein and live F17–positive E. coli bacteria. Good specificity and sensitivity for detection of F17–positive E. coli strains were obtained. The dynamic range for the biosensor varies from 1 × 102 to 1 × 109 CFU·mL−1 (R2 = 0.998) and the detection limit (LOD) and the IC50 value were estimated to be 37 CFU·mL−1 and 75 CFU·mL−1, respectively.
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