Genetic Diversity of Brucella melitensis Isolated from Domestic Ruminants in Iraq

Abstract

The control and eradication of brucellosis represents a critical objective for Veterinary and Health Authorities across several countries globally. Efficient surveillance programs play a pivotal role in detecting and managing outbreaks. Epidemiological investigations significantly benefit from standardized and efficient molecular typing techniques and analytical tools, enabling public health laboratories to identify the origin of outbreaks. This study aimed to sequence Brucella spp. strains isolated in Iraq from different ruminant species to verify their molecular epidemiological correlations and, above all, to shed a light on how these Iraqi isolates are positioned in the phylogenetic context of Brucella spp. The 35 isolates under study were from abortion, milk, placenta, and the fetal membranes of sheep, cattle, and buffalo. Genotyping involved various techniques: MLVA-16, Whole Genome Sequencing, MLST, and cgMLST. All the Iraqi isolates from our study clustered in MLVA-16 within the East Mediterranean clade, and all but one grouped together in the same branch of the MST tree. MST analysis showed the minimum distance of one allele between the studied isolates, except for one strain from buffalo, which was positioned farther away from the rest of the isolates. In cgMLST, the majority of strains grouped within a large cluster predominantly comprising genotypes from the Middle East. The application of different control measures in different territories based on molecular epidemiological studies would increase the chances of maximizing public health benefits and minimizing the spread of infection to disease-free or lower prevalence areas.