Evaluation of molecular typing methods for Salmonella enterica serovar Typhimurium DT104 isolated in Germany from healthy pigs

Abstract

-The discriminatory power of four different DNA based typing methods was tested for the molecular subtyping of Salmonella Typhimurium phage type DT104 isolates. German DT104 strains (n = 133) originating from slaughter pigs were analysed by plasmid profiling, and 32 of them by pulsed-field gel electrophoresis (PFGE) using the restriction enzymes XbaI, SpeI or BlnI, random amplification of polymorphic DNA (RAPD) using 13 different primers and IS200 typing. A resulting subtyping scheme was obtained which is based on the most discriminatory power of the individual methods i.e. plasmid profiling and PFGE with all three enzymes. The index of discrimination obtained by the subtyping scheme was 0.909 closely approaching the maximum value of one. Although minor differences occurred in the molecular DNA pattern of single DT104 strains, a dominating subtyping pattern was observed confirming other studies which showed, that S. Typhimurium DT104 isolates are highly clonal.

Multiple Genetic Typing of Salmonella enterica Serotype Typhimurium Isolates of Different Phage Types (DT104, U302, DT204b, and DT49) from Animals and Humans in England, Wales, and Northern Ireland

“…It has been reported that the majority of Salmonella serotype Typhimurium strains carry the serotype-specific plasmid of 60 MDa, alone or in combination with other plasmids. Plasmid profiling seems to present a reasonable degree of sensitivity when applied to Salmonella serotype Typhimurium (2,18,29). However, the inherent mobility of the plasmid DNA suggests instability of the characteristic under scrutiny.…”

“…Numerous genotypic methods have been used to subtype Salmonella serotype Typhimurium isolates, among them plasmid profiling (28,31), IS200 restriction fragment length polymorphism (3,19), ribotyping (8,21), pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA (5,24), random amplification of polymorphic DNA (18), and amplified fragment length polymorphism (16,26). Molecular typing analysis has indicated that DT104 isolates from different hosts and geographical origins are highly clonal (18,23).…”

“…Molecular typing analysis has indicated that DT104 isolates from different hosts and geographical origins are highly clonal (18,23). The aim of the present study was to assess the use of a multiple typing approach for sensitive differentiation of clones within animal and human Salmonella serotype Typhimurium isolates from some of the most relevant phage types in the United Kingdom.…”

Diagnostic Real-Time PCR for Detection of Salmonella in Food

“…These strains were from a selection recently published for a Salmonella validation study representing all known S. enterica subspecies enterica and S. bongori strains (20). S. enterica serotype Typhimurium phage type DT104 strain 51K61, isolated in 1996 from pig feces, was used as the reference strain (22). Eighty-seven non-Salmonella strains were used for the exclusivity tests (Table 1).…”

Molecular Characterization of Multiresistant d -Tartrate-Positive Salmonella enterica Serovar Paratyphi B Isolates

“…Genomic DNA for pulsed-field gel electrophoresis (PFGE) experiments was prepared in low-melting-point agarose gel plugs as previously described (23). Slices of the DNA-containing agarose plugs were incubated in a final volume of 100 l overnight at 37°C with 10 U of XbaI, SpeI, or BlnI (all from Roche Diagnostics).…”