AUTHOR=Girault Guillaume , Freddi Luca , Jay Maryne , Perrot Ludivine , Dremeau Alexandre , Drapeau Antoine , Delannoy Sabine , Fach Patrick , Ferreira Vicente Acacia , Mick Virginie , Ponsart Claire , Djokic Vitomir 

TITLE=Combination of in silico and molecular techniques for discrimination and virulence characterization of marine Brucella ceti and Brucella pinnipedialis

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1437408

DOI=10.3389/fmicb.2024.1437408

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Mammals are the main hosts for <italic>Brucella</italic> sp., agents of worldwide zoonosis. Marine cetaceans and pinnipeds can be infected by <italic>Brucella ceti</italic> and <italic>B. pinnipedialis</italic>, respectively. Besides classical bacteriological typing, molecular approaches such as MLVA, MLSA, and whole-genome sequencing (WGS) can differentiate these species but are cumbersome to perform.</p></sec><sec><title>Methods</title><p>We compared the DNA and genome sequences of 12 strains isolated from nine marine mammals, with highly zoonotic <italic>B. melitensis</italic>, <italic>B. abortus</italic>, and <italic>B. suis</italic>, and the publicly available genomes of <italic>B. ceti</italic> and <italic>B. pinnipedialis. In silico</italic> pipelines were used to detect the antimicrobial resistance (AMR), plasmid, and virulence genes (VGs) by screening six open-source and one home-made library.</p></sec><sec><title>Results and discussion</title><p>Our results show that easier-to-use HRM-PCR, Bruce-ladder, and Suis-ladder can separate marine <italic>Brucella</italic> sp., and the results are fully concordant with other molecular methods, such as WGS. However, the restriction fragment length polymorphism (RFLP) method cannot discriminate between <italic>B. pinnipedialis</italic> and <italic>B. ceti</italic> B1-94-like isolates. MLVA-16 results divided the investigated strains into three clades according to their preferred host, which was confirmed in WGS. <italic>In silico</italic> analysis did not find any AMR and plasmid genes, suggesting antimicrobial susceptibility of marine <italic>Brucella</italic>, while the presence of the VGs <italic>btpA</italic> gene was variable dependent on the clade.</p></sec><sec><title>Conclusion</title><p>The HRM-PCR and Suis-ladder are quick, easy, and cost-effective methods to identify marine <italic>Brucella</italic> sp. Moreover, <italic>in silico</italic> genome analyses can give useful insights into the genetic virulence and pathogenicity potential of marine <italic>Brucella</italic> strains.</p></sec>