title: A multi locus variable number of tandem repeat analysis (MLVA) scheme for Streptococcus agalactiae genotyping.
abstract: BACKGROUND
  Multilocus sequence typing (MLST) is currently the reference method for genotyping Streptococcus agalactiae strains, the leading cause of infectious disease in newborns and a major cause of disease in immunocompromised children and adults. We describe here a genotyping method based on multiple locus variable number of tandem repeat (VNTR) analysis (MLVA) applied to a population of S. agalactiae strains of various origins characterized by MLST and serotyping.
  
  
  RESULTS
  We studied a collection of 186 strains isolated from humans and cattle and three reference strains (A909, NEM316 and 2603 V/R). Among 34 VNTRs, 6 polymorphic VNTRs loci were selected for use in genotyping of the bacterial population. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each VNTR locus. 98 MLVA genotypes were obtained compared to 51 sequences types generated by MLST. The MLVA scheme generated clusters which corresponded well to the main clonal complexes obtained by MLST. However it provided a higher discriminatory power. The diversity index obtained with MLVA was 0.960 compared to 0.881 with MLST for this population of strains.
  
  
  CONCLUSIONS
  The MLVA scheme proposed here is a rapid, cheap and easy genotyping method generating results suitable for exchange and comparison between different laboratories and for the epidemiologic surveillance of S. agalactiae and analyses of outbreaks.
authors.affiliation: Université François-Rabelais de Tours, UFR de Médecine, EA 3854 Bactéries et risque materno-fœtal, Institut Fédératif de Recherche 136 Agents Transmissibles et Infectiologie, Tours, France.
authors.forename: Eve
authors.initials: E
authors.lastname: Haguenoer
authors.forename: Gaelle
authors.initials: G
authors.lastname: Baty
authors.forename: Christine
authors.initials: C
authors.lastname: Pourcel
authors.forename: Marie-Frédérique
authors.initials: MF
authors.lastname: Lartigue
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Domelier
authors.forename: Agnès
authors.initials: A
authors.lastname: Rosenau
authors.forename: Roland
authors.initials: R
authors.lastname: Quentin
authors.forename: Laurent
authors.initials: L
authors.lastname: Mereghetti
authors.forename: Philippe
authors.initials: P
authors.lastname: Lanotte
mesh_terms: D000328:Adult; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004812:Epidemiologic Methods; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D018598:Minisatellite Repeats; D058889:Molecular Typing / Q000191:economics / Q000379:methods*; D011110:Polymorphism, Genetic; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary; D013292:Streptococcus agalactiae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D013997:Time Factors