Brucella Prevalent Strains Circulating in Egypt during 2020-2021: Bacteriological and Molecular Study

Brucellosis is a major constraint to livestock production that still enzootic in livestock in many developing countries including Egypt. This study was conducted with the general objective of establishing the bacteriological status of bovine brucellosis in 15 governorates in Egypt during 2020-2021 to determine the circulating Brucella species on bacteriological and molecular basis. Clinical samples collected included milk or udder secretions, vaginal discharges, fetal membranes and stomach contents of aborted fetuses from dairy cows with history of brucellosis. In addition, lymph nodes (retropharyngeal, prescapular, prefemoral, internal iliac and supramammary) from carcasses of serologically positive animals were obtained from different localities for isolation and identification of Brucella organisms. A total of 136 Brucella isolates were recovered from cattle in different governorates, Egypt. These include, 107 isolates of Brucella melitensis biovar 3 identified on bacteriological and molecular basis from Aswan, Beheira,  Beni Suef, Dakahlia, Damietta, Fayoum, Gharbia, Giza, Ismailia, Kafr El-Sheikh, Luxor, Monufia, Port Said, Qalyubia and Sharqia governorates. On the other hand, 29 Brucella abortus biovar 1 isolates were recovered from cattle from Beni Suef, Dakahlia, Damietta, Kafr El-Sheikh, Monufia, Port Said and Sharqia governorates. Molecular identification using primer sequences targeting IS711 gene confirmed Brucella on genus level. Multiplex PCR has amplified four fragments of 450bp, 587 bp, 1071 bp, and1682 bp characteristic for B. melitensis biovar 3, and three fragments of 450bp, 587 bp, and 1682 bp for B. abortus biovar 1. The identification of Brucella spp. in different farm animals of 15 Egyptian governorates highlights the dynamics and role of cattle in dissemination of Brucella infection all over the country.  The obtained results indicate that the actual Brucellosis status during the years 2020 and 2021 refers to that B. melitensis biovar 3 and B. abortus biovar 1 are the prevalent types circulating in different Egyptian governorates.