Showing papers by "Stefan Schwarz published in 1994"

Use of ribotyping, IS200 typing and plasmid analysis for the identification of Salmonella enterica subsp. enterica serovar Typhimurium vaccine strain Zoosaloral H and its differentiation from wild type strains of the same serovar.

Abstract: Fifty Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates obtained from one vaccinated and three non-vaccinated poultry flocks as well as the commercially available vaccine strain Zoosaloral H and a S. Typhimurium reference strain were characterized genotypically to differentiate between S. Typhimurium live vaccine strain Zoosaloral H and wild type strains of the same serovar. Ribotyping revealed five different patterns one of which exclusively occurred in the vaccine strain. Seven different hybridization patterns could be observed by IS200-typing of the S. Typhimurium isolates; one of them was only detectable in the vaccine strain. Plasmid analysis showed that 51% of the S. Typhimurium isolates including the vaccine strain harboured large plasmids of approximately 60 MDa. Hybridization with a virulence gene probe identified only 48% of these large plasmids, including that of the vaccine strain, to carry this virulence-associated gene. However, restriction endonuclease analysis of the hybridizing plasmids showed that the virulence gene was located on HindIII fragments of different sizes in the plasmid of the S. Typhimurium vaccine strain Zoosaloral H and in the plasmids of the respective wild type S. Typhimurium isolates. Thus, ribotyping, IS200-typing and plasmid analysis represent at least three independent systems which allow the genotypic identification of the S. Typhimurium vaccine strain Zoosaloral H and its differentiation from wild type isolates of the same serovar.

Pulsed-field gel electrophoretic identification of Salmonella enterica serovar Typhimurium live vaccine strain Zoosaloral H

Abstract: Salmonella enterica subsp. enterica serovar Typhimurium (Salm. Typhimurium) live vaccine strain Zoosaloral H was characterized by pulsed-field gel electrophoresis (PFGE). Each of the two suitable restriction enzymes, XbaI and SpeI, produced a unique restriction fragment pattern for this live vaccine strain which was not shared by field isolates of the same serovar. The characteristic fragment pattern proved to be stable during a 22 month observation period and was also not altered after animal passage of the vaccine strains. Thus PFGE analysis proved to be a helpful tool in the identification of Salm. Typhimurium live vaccine strain Zoosaloral H and its differentiation from wild-type isolates of the same serovar.

Structure and putative origin of a plasmid from Staphylococcus hyicus that mediates chloramphenicol and streptomycin resistance

Abstract: The structure and functional organization of Staphylococcus hyicus plasmid pSCGp3EB that mediates chloramphenicol and streptomycin resistance (CmrSmr) is described and compared with another CmrSmr plasmid, pSCS12, from Staphylococcus sciuri. Both plasmids appeared to be formed by co-integrate formation between plasmids that very closely resemble the chloramphenicol resistance (Cmr) plasmid pC221 and the streptomycin resistance (Smr) plasmid pS194. In addition to the established recombination site B (RSB) in pC221 and pS194, another area suitable for recombination immediately downstream of the cat gene in pC221 and upstream of the str gene in pS194 has been identified. Co-integration at these sites would lead to the structures we have observed in the wild-type CmrSmr plasmids pSCGp3EB and pSCS12.