AUTHOR=Liu Yan , Wang Ziyan , Wang Ze , Zhou Jun , Han Jiaojiao , Lu Chenyang , Liu Bing , Yu Rongxian , Sun Xiaoling , Zhang Zhen , Wang Rixin , Su Xiurong 

TITLE=Rapid and simultaneous multiepitope antigen-based detection of Enterococcus by microscale thermophoresis and immunomagnetic separation

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1341451

DOI=10.3389/fmicb.2024.1341451

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p>Generally, enterococci bacteria cause nosocomial infections and are major indicators of bacterial contamination in marine bathing beach. However, a method for the rapid and simultaneous detection of multiple pathogenic enterococci has not been developed on account of the wide variety of pathogenic enterococci and their existence in complex matrices.</p></sec><sec><title>Methods</title><p>Immunoinformatics tools were used to design a multi-epitope antigen for the detection of various pathogenic enterococci by using the sequence of dltD gene on enterococci lipoteichoic acid (LTA) surface, which is associated with toxicological effects. The multi-epitopes included enterococci such as <italic>Enterococcus faecalis</italic>, <italic>E. gallinarum</italic>, <italic>E. raffinosus</italic>, <italic>E. durans</italic>, <italic>E. faecium</italic>, <italic>E. hirae</italic>, <italic>E. thailandicus</italic>, <italic>E. casseliflavus</italic>, <italic>E. avium</italic>, <italic>E. mundtii</italic>, <italic>E. lactis</italic>, <italic>E. solitarius</italic>, <italic>E. pseudoavium</italic>, and <italic>E. malodoratum</italic>. Microscale thermophoresis (MST) and western blot were carried out to detect the affinity between multi-epitope antigens and antibodies and between multi-epitope antibodies and bacteria. Furthermore, the detection of pathogenic enterococci was carried out by using immunomagnetic beads (IMBs) and immune chromatographic test strip (ICTS).</p></sec><sec><title>Results</title><p>The multi-epitope antibody had a satisfactory affinity to the antigen and enterococci. IMBs and ICTS were detected with a minimum of 101 CFU/mL and showed incompatibility for <italic>Vibrio parahemolyticus</italic>, <italic>V. vulnifcus</italic>, <italic>V. harveyi</italic>, <italic>V. anguillarum</italic>, and <italic>Edwardsiella tarda</italic>.</p></sec><sec><title>Implication</title><p>The present study demonstrated that the multi-epitope antigens exhibited excellent specificity and sensitivity, making them highly suitable for efficient on-site screening of enterococci bacteria in marine bathing beaches.</p></sec>