title: Multilocus variable-number tandem-repeat analysis for subtyping Salmonella enterica serovar Gallinarum.
abstract: Salmonella enterica serovar Gallinarum causes a severe systemic disease, fowl typhoid, primarily in chickens and turkeys, and it remains a disease of worldwide significance. Multilocus variable-number tandem-repeat analysis (MLVA) has proved to be very useful for subtyping other Salmonella serovars. We describe the development of a simple MLVA assay for S. enterica serovar Gallinarum that is comparable with pulsed-field gel electrophoresis (PFGE) in resolution. The genome sequence of S. enterica serovar Gallinarum strain 287/91 was analysed for potential variable-number tandem repeats (VNTRs) and then polymerase chain reaction assays were developed to assess the variability of the loci. Four VNTR markers were selected and used in a multiplex fragment analysis assay. The stability of the VNTR markers was assessed by conducting in vitro passage experiments with two strains (95 clones per strain) over a 30-day period. A MLVA of 68 strains of S. enterica serovar Gallinarum based on the four VNTR loci distinguished 26 allelic profiles. The MLVA assay showed a Simpson's diversity index of 0.918, whereas PFGE analysis produced 23 patterns and had a diversity index of 0.874. Most importantly, the MLVA further discriminated strains having the same PFGE pattern. The MLVA assay is a highly discriminatory genotyping method for S. enterica serovar Gallinarum. Therefore, MLVA can be a useful addition to routine PFGE analysis for molecular epidemiological investigation of fowl typhoid.
authors: National Veterinary Research & Quarantine Service, Ministry for Food, Agriculture, Forestry and Fisheries, Anyang, Gyeonggi, Republic of Korea.kangmskr@korea.kr
authors: Min S
authors: MS
authors: Kang
authors: Yong K
authors: YK
authors: Kwon
authors: Jae Y
authors: JY
authors: Oh
authors: Douglas R
authors: DR
authors: Call
authors: Byung K
authors: BK
authors: An
authors: Eun A
authors: EA
authors: Song
authors: Jeong Y
authors: JY
authors: Kim
authors: Eun G
authors: EG
authors: Shin
authors: Mi J
authors: MJ
authors: Kim
authors: Jun H
authors: JH
authors: Kwon
authors: Gab S
authors: GS
authors: Chung
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005819:Genetic Markers / Q000235:genetics*; D014644:Genetic Variation; D018598:Minisatellite Repeats / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011200:Poultry / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification / Q000235:genetics*
chemical_list: D005819:Genetic Markers