title: Molecular characterization of Salmonella Enteritidis: comparison of an optimized multi-locus variable-number of tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis.
abstract: Salmonella Enteritidis (SE) is a genetically homogenous serovar, which makes optimal subtype discrimination crucial for epidemiological research. This study describes the development and evaluation of an optimized multiple-locus variable number tandem-repeat assay (MLVA) for characterization of SE. The typeability and discriminatory power of this MLVA was determined on a selected collection of 60 SE isolates and compared with pulsed-field gel electrophoresis (PFGE) using restriction enzymes XbaI, NotI, or SfiI. In addition, the estimated Wallace coefficient (W) was calculated to assess the congruence of the typing methods. Selection of epidemiologically unrelated isolates and more related isolates (originating from layer farms) was also based on the given phage type (PT). When targeting six loci, MLVA generated 16 profiles, while PFGE produced 10, 9, and 16 pulsotypes using XbaI, NotI, and SfiI, respectively, for the entire strain collection. For the epidemiologically unrelated isolates, MLVA had the highest discriminatory power and showed good discrimination between isolates from different layer farms and among isolates from the same layer farm. MLVA performed together with PT showed higher discriminatory power compared to PFGE using one restriction enzyme together with PT. Results showed that combining PT with the optimized MLVA presented here provides a rapid typing tool with good discriminatory power for characterizing SE isolates of various origins and isolates originating from the same layer farm.
authors.affiliation: Technology and Food Science Unit, Institute for Agricultural and Fisheries Research, Melle, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dewaele
authors.forename: Geertrui
authors.initials: G
authors.lastname: Rasschaert
authors.forename: Sophie
authors.initials: S
authors.lastname: Bertrand
authors.forename: Christa
authors.initials: C
authors.lastname: Wildemauwe
authors.forename: Pierre
authors.initials: P
authors.lastname: Wattiau
authors.forename: Hein
authors.initials: H
authors.lastname: Imberechts
authors.forename: Lieve
authors.initials: L
authors.lastname: Herman
authors.forename: Richard
authors.initials: R
authors.lastname: Ducatelle
authors.forename: Koen
authors.initials: K
authors.lastname: De Reu
authors.forename: Marc
authors.initials: M
authors.lastname: Heyndrickx
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods*; D004262:DNA Restriction Enzymes / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D018598:Minisatellite Repeats; D012477:Salmonella enteritidis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes