Groussaud et al. [25] analysed the diversity of marine mammal isolates by MLVA using another selection of VNTRs, including all 8 loci defining the HOOF-prints MLVA assay described by Bricker et al. [16] and 13 additional loci characterised by Le Flèche et al. [17] and Whatmore et al. [18]. This panel of 21 VNTR loci MEK activation corresponded to a 21-locus MLVA scheme sharing 9 loci with MLVA-16 and also provides
a high degree of diversity. In this previous study, multilocus sequence types (STs) were determined, allowing the clustering of marine mammal isolates in five groups labelled ST23 to ST27. The closely related ST24 and ST25 were composed of the pinniped isolates, forming the cluster C. The hooded seal isolates define subcluster C3. ST26 was exclusively composed of dolphin isolates and formed the cluster A. The other cetacean isolates all clustered in the cluster B (ST23) and consisted of strains isolated from porpoises and dolphins. ST27 was represented by only one
isolate from an aborted bottlenose dolphin foetus originating from the Western coast of the United States (strain F5/99) [28]. Our results are thus in excellent accordance with those published by Groussaud et al. [25] showing that the previously identified population structure of marine mammal Brucella strains is not significantly selleck kinase inhibitor modified by the inclusion of a large number of strains from European waters. MLVA-16 results are also in accordance with the recently reported genomic structures of 24 marine mammal Brucella isolates for which three subgroups were identified [32]. In that ZD1839 study, one separate group was identified for the B. pinnipedialis strains, another subgroup included dolphin
isolates and a third subgroup comprised dolphin and porpoise isolates. The only hooded seal isolate analysed in that study clustered in the B. pinnipedialis group but revealed a separate pattern with a 62 kb missing fragment, specific for this group and relevant for a distinct genetic background [32]. MLVA-16 classification in the present report revealed some exceptions like the M490/95/1 strain, isolated from a common seal, which was clustered in the B. ceti group of strains. This exception suggests that transmission from cetaceans to pinnipeds may occur. Although the currently recognized terrestrial mammal Brucella species also have a preferred host, they can be isolated from different hosts in regions where brucellosis is endemic, e.g. B. melitensis which has been isolated from cattle in the southern part of France [33]. The human isolate from New Zealand formed a separate seventh MLVA-16 cluster. Whatmore et al. [28] have shown that the F5/99 strain, isolated from an aborted bottlenose dolphin fetus from the Western coast of the United States (together with three human isolates, one from New Zealand and two from Peru) shared the same MLST genotype (ST27).