Salmonella enterica Phage Typing for Subtype Analysis of Pulsed-Field Gel Electrophoresis, and Variable-Number Tandem Repeat Analysis, Comparison of Multiple-Locus

serotype Enteritidis. The discrimination ability and epidemiologicalconcordance of MLVA were compared with those of pulsed-field gel electrophoresis (PFGE) and phage typing.MLVA provided greater discrimination among non-epidemiologically linked isolates than did PFGE or phagetyping. Epidemiologic concordance was evaluated by typing 40 isolates from four food-borne disease outbreaks.MLVA, PFGE, and, to a lesser extent, phage typing exhibited consistent subtypes within an outbreak. MLVAwas better able to differentiate isolates between the individual outbreaks than either PFGE or phage typing.The reproducibility of MLVA was evaluated by subtyping sequential isolates from an infected individual andby testing isolates following multiple passages and freeze-thaw cycles. PFGE and MLVA patterns werereproducible for isolates that were frozen and passaged multiple times. However, 2 of 12 sequential isolatesobtained from an individual over the course of 36 days had an MLVA type that differed at one locus and oneisolate had a different phage type. Overall, MLVA typing of