MOLECULAR CHARACTERIZATION OF SALMONELLA-ENTERICA SUBSP ENTERICA SEROVAR TYPHIMURIUM DT009 ISOLATES - DIFFERENTIATION OF THE LIVE VACCINE STRAIN ZOOSALORAL FROM FIELD ISOLATES

A total of 25 epidemiologically unrelated Salmonella enterica subsp. e nrerica (S.) serovar Typhimurium DT009 isolates from various human and animal sources, the original S. Typhimurium DT009 Zoosaloral live vac cine strain and two Zoosaloral strains reisolated from vaccinated chic kens were investigated by various molecular typing methods (I) to dete rmine the most suitable method or combination of methods for the diffe rentiation of DT009 field isolates and (II) to investigate which molec ular methods are suitable to differentiate the Zoosaloral live vaccine strain from field isolates of the same phage type. Based on the resul ts of plasmid profile analysis, IS200 typing and macrorestriction anal ysis with XbaI, SpeI and BlnI, the 28 S. Typhimurium DT009 isolates we re assigned to 16 different genomic groups, one of which was exclusive ly represented by the original and the reisolated Zoosaloral strains. IS200 typing was the most discriminatory single method for the differe ntiation of the DT009 isolates followed by plasmid profile analysis an d BlnI-macrorestriction analysis. The Zoosaloral vaccine strain differ ed from the DT009 field isolates by its unique HindIII-fragment patter n of the virulence plasmid and by its unique SpeI macrorestriction pat tern. (C) 1998 Federation of European Microbiological Societies. Publi shed by Elsevier Science B.V. All rights reserved.