title: Use of multiple-locus variable-number tandem-repeats analysis (MLVA) typing to characterize Salmonella Typhimurium DT41 broiler breeder infections.
abstract: OBJECTIVE
  To characterize isolates of Salmonella Typhimurium DT41 obtained from infected flocks of broiler breeders by multiple-locus variable-number tandem-repeats analysis (MLVA) and compare results with a diverse strain collection from Germany and United Kingdom and isolates from Danish patients.
  
  
  RESULTS
  A total of 102 isolates of Salm. Typhimurium phage type DT41 were MLVA typed. MLVA typing showed 4, 12, 25, 9 and 8 different alleles at the five MLVA loci 9, 5, 6, 10 and 3, respectively. A dendrogram based on MLVA types was constructed, and one large group, nine minor groups and 29 more unrelated MLVA types were obtained. The major group included 20 of the 30 human isolates. Isolates obtained from broiler breeders demonstrated major diversity, indicating the existence of several independent introductions of DT41 at farm level. When comparison was made to isolates included from Germany and England, DT41 seems to be ubiquitous in the wild fauna which might represent a risk factor for poultry.
  
  
  CONCLUSIONS
  Transmission from Danish broilers to humans was not demonstrated, neither was the transmission from rearing farms to broiler breeder farms. Sources of infection at broiler breeder farm level remained unidentified.
  
  
  CONCLUSIONS
  Major diversity was demonstrated for DT41 MLVA types. A persisting problem with infection of broiler breeder flocks with DT41 was not reflected in broiler flocks originating from these flocks.
authors.affiliation: Statens Serum Institut, Copenhagen S, Denmark. evl@ssi.dk
authors.forename: E
authors.initials: E
authors.lastname: Litrup
authors.forename: H
authors.initials: H
authors.lastname: Christensen
authors.forename: S
authors.initials: S
authors.lastname: Nordentoft
authors.forename: E M
authors.initials: EM
authors.lastname: Nielsen
authors.forename: R H
authors.initials: RH
authors.lastname: Davies
authors.forename: R
authors.initials: R
authors.lastname: Helmuth
authors.forename: M
authors.initials: M
authors.lastname: Bisgaard
mesh_terms: D000483:Alleles; D000818:Animals; D001434:Bacteriophage Typing; D002645:Chickens / Q000382:microbiology*; D003718:Denmark; D014644:Genetic Variation; D005858:Germany; D006801:Humans; D018598:Minisatellite Repeats; D058885:Multilocus Sequence Typing; D011201:Poultry Diseases / Q000382:microbiology; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006113:United Kingdom