Molecular and Proteomic Identification of some Abortificient pathogens in cattle

Abstract: The goal of this study was to enhance the diagnosis by quickly and accurately finding pathogens that cause abortion using molecular and proteomic methods. This would be a huge step forward in control programs and help avoid huge economic losses. A total of 148 aborted cases occurred between 2019 and 2024 in different Egyptian farms. Aborted fetuses yielded a total of 298 different samples. We directly subjected all samples to molecular investigation, which included both monoplex and multiplex as well as real-time PCR. We grew PCR samples that were positive on special media so that we could use MALDI-TOF to get a better look at the proteins. In that order, we were able to get positive amplicons of 223 bp, 270 bp, and 370 bp that were specific for Brucella, Mycoplasma, and Listeria. Brucella was the most common pathogen detected, followed by Mycoplasma and then Listeria. Real-time PCR confirmed the results by identifying specific melting peaks in positive samples. Results of bacterial culture revealed Brucella n=30 and Mycoplasma n=17, while Listeria couldn't be cultured. It was clear from the MALDI-TOF culture that Brucella spp. (16), Brucella melitensis (1), and Achromobacter (9) were all there and growing well. While for Mycoplasma, 4/17 were Bovigenitalium. Multiplex PCR can be used to successfully find and tell the difference between Brucella, Mycoplasma, and Listeria all at the same time from clinical samples. The MALDI-TOF results were excellent for Brucella but not so good for Mycoplasma spp. Direct detection from organs using MALDI-TOF is still not possible, so more research needs to be done. Finally, MALDI-TOF cannot fully replace the use of conventional and molecular assays.