Geographical distribution
Genetic similarity of different genotypes from different districts were identified (Figure 1). The two strains of genotype M13_K.E have 99 % genetic similarity with the four strains of M10_K.E genotype and the three strains of M9_K.E genotype. The same degree of similarity was also found between M1_K.E and M7_K.E genotypes, M4_K.E and the two strains of M14_K.E genotype, M15_K.E and the five strains of M16_K.E as well as between the two strains of M18_K.E genotype and each of the eight strains of M17_K.E genotype and finally between the two strains of M2_K.E, M11_K.E and M19_K.E genotypes. High genetic similarity of 98.5 %, 98.3%, 98 %, 97.6 %, 97.2 % and lower are shown in Figure 1.
The relatedness and association of genotypes MLVA-16 data in our study with those previously reported in Egypt is shown in the dendrogram, Figure 2. Genotypes 61-Egy-Bm3-Sharq and 18-Egy-Bm3-Kshkh isolated from Sharqia and Kafrelsheikh governorates (Sayour et al., 2020) are 100% identical with our genotypes M17_K.E and M11_K.E, respectively. Out of the 118 Brucella strains, 115 were grouped with the 41 B. melitensis strains of this study into one cluster with a similarity coefficient of approximately 96%, Figure 2.
A wider comparison with the worldwide MLVA-16 metadata of 385 B. melitensis bv3 ( Le Fleche et al., 2006; Al Dahouket al., 2007; Marianelli et al., 2007; Kilic et al., 2011; Garofolo et al., 2013; Vergnaud et al.,2018) is illustrated in the dendrogram of “Supplementary file 1” as well as the similarity coefficient-based minimum spanning tree, Figure 3.
All genotypes and strains identified in this study belonged mainly to the Western Mediterranean clonal lineage and were less likely related to the Americas clonal lineage. The highest similarity percentages were with neighbourhood Mediterranean and European countries. M12_K.E genotype is of 97 % similarity with genotypes 2018Vergnaud#0133 and 2007AlDahouk#013 which were isolated from humans in France (1978) and Tunisia (1992), respectively. M3_K.E genotype is 99 % similar to the French genotypes 2018Vergnaud#0531 and 2018Vergnaud#0555 which were isolated in 1983 from cattle. M14_K.E genotype is 99 % similar to genotypes 2018Vergnaud#0381 and 2018Vergnaud#0408 isolated from humans in Belgium (1982) which in turn have a similarity of 98.5 % with M4_K.E genotype.
M13_K.E, M10_K.E, M9_K.E, and M5_K.E genotypes are 97.8 % similar to 2013Garofolo_6844 and 2018Vergnaud#0928 genotypes which were isolated from ovine in Italy (2011) and France (1980), respectively, and represented a similarity of 97.2 % with M1_K.E, M7_K.E and M6_K.E genotypes. M8_K.E genotype is 98 % similar to 17 genotypes that were isolated from humans and different animals in France and Italy during the period 1978 to 1999. M16_K.E, M15_K.E, M18_K.E, M17_K.E, M11_K.E, M19_K.E, and M2_K.E have 98 % similarity with 18 genotypes originated from humans, ovine, and cattle in Italy and France during the period 1979 to 2011.