Whole-Genome Sequencing of <italic>Brucella melitensis</italic> Isolates from Kuwait for the Identification of Biovars, Variants, and Relationship within a Biovar.

<bold><italic>Objective:</italic></bold> The identification of <italic>Brucella</italic> genotypes is essential for epidemiological studies. The whole-genome sequencing is emerging as a novel tool for genetic characterization of infectious microbes. The aim of this study was to genotype <italic>Brucella melitensis</italic> isolates from Kuwait using whole-genome sequencing and variant analysis of the sequence data. <bold><italic>Methods:</italic></bold> DNA was purified from 15 heat-inactivated <italic>B. melitensis</italic> isolates and used to prepare sequencing libraries employing Nextera XT DNA Sample Preparation Kit (Illumina San Diego, CA, USA) and sequenced on a MiSeq (Illumina). The sequence files were aligned to three biovars of <italic>B. melitensis</italic>, i.e., biovar 1 str. 16M, biovar 2 str. 63/9, and biovar 3 str. Ether. The alignment and variant calling were performed using “bwa-mem” and SAMtools/VCFtools, respectively. <bold><italic>Results:</italic></bold> The genome size of all the isolates was around 3.3 mega base pairs and resembled <italic>B. melitensis</italic> biovar 2. Single-nucleotide polymorphisms (SNPs), insertions, and deletions (indels) were spread all over the genome; but 138 SNPs were common among the 14 isolates, supporting the same ancestral origin. A neighbor-joining tree analysis identified isolate 2 as an outlier. In addition, SNPs (2–478) specific to each isolate were also identified, which divided the <italic>B. melitensis</italic> biovar 2 into two major groups/genotypes. A further analysis showed that the Kuwaiti isolates of the present study shared phylogeny mainly with strains from the Middle Eastern countries. <bold><italic>Conclusions:</italic></bold> Among the 15 studied isolates from Kuwait, biovar 2 is the most prevalent biovar of <italic>B. melitensis</italic>. Furthermore, isolate-specific genetic variations were identified, which may be useful in epidemiological investigations. [ABSTRACT FROM AUTHOR]