Brucellosis outbreak in a Swedish kennel in 2013: Determination of genetic markers for source tracing

• Published in: Veterinary microbiology 2014-12, Vol.174 (3-4), p.523-530
• Main Authors: Kaden, Rene, Ågren, Joakim, Båverud, Viveca, Hallgren, Gunilla, Ferrari, Sevinc, Börjesson, Joann, Lindberg, Martina, Bäckman, Stina, Wahab, Tara
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Biologi med inriktning mot mikrobiologi; Biologi med inriktning mot molekylärbiologi; Biology with specialization in Microbiology; Biology with specialization in Molecular Biology; Brucella; Brucella canis; Brucella canis - genetics; Brucella canis - isolation & purification; Brucellosis; Brucellosis - epidemiology; Brucellosis - microbiology; Brucellosis - veterinary; Canis; Clustered-regularly-interspaced short palindromic repeats (CRISPR); Disease Outbreaks - veterinary; Dog Diseases - epidemiology; Dog Diseases - microbiology; Dogs; Female; Forensic Medicine; Genetic Markers - genetics; Genome, Bacterial - genetics; Humans; Infectious Diseases; Infektionssjukdomar; Male; Molecular Sequence Data; Real-Time Polymerase Chain Reaction - veterinary; Roseobacter; Rättsmedicin; Sequence Analysis, DNA - veterinary; Source tracing; Species Specificity; Sweden - epidemiology; Whole genome sequencing phage analysis (WGS-PA); Zoonoses; Zoonosis
• ISSN: 0378-1135; 1873-2542; 1873-2542
• DOI: 10.1016/j.vetmic.2014.10.015

•We developed a Brucella canis specific real time PCR.•We describe an outbreak of canine brucellosis including the epidemiological aspects.•The whole genome of the Brucella canis outbreak strain was sequenced and analysed.•We detected genetic markers for source tracing in the genome of Brucella canis. Brucellosis is a highly infectious zoonotic disease but rare in Sweden. Nonetheless, an outbreak of canine brucellosis caused by an infected dog imported to Sweden was verified in 2013. In total 25 dogs were tested at least duplicated by the following approaches: real-time PCR for the detection of Brucella canis, a Brucella genus-specific real-time PCR, selective cultivation, and microscopic examination. The whole genome of B. canis strain SVA13 was analysed regarding genetic markers for epidemiological examination. The genome of an intact prophage of Roseobacter was detected in B. canis strain SVA13 with whole genome sequence prophage analysis (WGS-PA). It was shown that the prophage gene content in the American, African and European isolates differs remarkably from the Asian strains. The prophage sequences in Brucella may therefore serve of use as genetic markers in epidemiological investigations. Phage DNA fragments were also detected in clustered, regularly interspaced short palindromic repeats (CRISPR) in the genome of strain SVA13. In addition to the recommendations for genetic markers in Brucella outbreak tracing, our paper reports a validated two-step stand-alone real-time PCR for the detection of B. canis and its first successful use in an outbreak investigation.