Phenotypic and molecular characterization of a Brucella strain isolated from a minke whale (Balaenoptera acutorostrata).
Isolation of Brucella spp. in marine mammals has been reported during the past several years. A Brucella strain from the spleen and liver of a minke whale (Balaenoptera acutorostrata) was isolated. Conventional typing methods indicated that this isolate was related to the genus Brucella but did not match the profiles of any known Brucella species or biovar. Successful PCR amplification of the Brucella rrs-rrl spacer sequence and of the insertion sequence IS6501 also indicated that the minke whale strain was related to the genus Brucella. In addition, the rrs gene of this strain shared a very high degree of nucleotide identity (>98%) with published Brucella spp. rrs sequences. However, RFLP studies using an IS6501-specific probe showed a unique profile for this strain in comparison with the profiles of the six known Brucella species. Moreover, analysis of the omp2 locus by PCR-RFLP, by Southern hybridization using omp2a- and omp2b-specific probes, and by DNA sequencing showed that the minke whale isolate possesses two copies of the omp2b gene instead of one omp2a and one omp2b gene copy or two copies of the omp2a gene described in the six known Brucella species. Thus, molecular typing methods showed that this isolate is clearly distinct from all other known Brucella species and strains. The specific molecular features of this minke whale Brucella isolate raise questions about the lineage between the Brucella strains isolated from marine mammals and the Brucella species isolated from terrestrial mammals.
Clavareau
Chantal
C
Centre d'Etude et de Recherches Vétérinaires et Agrochimiques,99 Groeselenberg, B-1180 Brussels,Belgium.
Wellemans
Vincent
V
Centre d'Etude et de Recherches Vétérinaires et Agrochimiques,99 Groeselenberg, B-1180 Brussels,Belgium.
Walravens
Karl
K
Centre d'Etude et de Recherches Vétérinaires et Agrochimiques,99 Groeselenberg, B-1180 Brussels,Belgium.
Tryland
Morten
M
Norwegian College of Veterinary Medicine, Department of Arctic Veterinary Medicine,N-9005 Tromsø,Norway.
Verger
Jean-Michel
JM
Institut National de la Recherche Agronomique, Laboratoire de Pathologie Infectieuse et Immunologie,F-37380 Nouzilly,France.
Grayon
Maggy
M
Institut National de la Recherche Agronomique, Laboratoire de Pathologie Infectieuse et Immunologie,F-37380 Nouzilly,France.
Cloeckaert
Axel
A
Institut National de la Recherche Agronomique, Laboratoire de Pathologie Infectieuse et Immunologie,F-37380 Nouzilly,France.
Letesson
Jean-Jacques
JJ
Facultés Universitaires Notre-Dame de la Paix, Unité d'lmmunologie-Microbiologie,B-5000 Namur,Belgium.
Godfroid
Jacques
J
Centre d'Etude et de Recherches Vétérinaires et Agrochimiques,99 Groeselenberg, B-1180 Brussels,Belgium.
D000818:Animals; D001426:Bacterial Proteins; D002002:Brucella / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000032:analysis; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018272:Porins / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D014907:Whales / Q000382:microbiology*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; C096736:Omp2b protein, Brucella; D018272:Porins; D012335:RNA, Ribosomal