Clonal relationship of Salmonella enterica serovar typhimurium phage type DT104 in Germany and Austria

Abstract

A new epidemic clone of Salmonella enterica serovar Typhimurium designated definitive phage type (DT) 104 has been emerging since 1990 to become most common type among S. Typhimurium isolates in Germany and Austria. Molecular fingerprinting (PFGE-pattern, plasmid profiles, IS200 pattern, ribotype, ERIC-type, OMP and MLE patterns) revealed the majority of the DT104 isolates to have clonal identity; they were designated as type 1 (about 95%). Moreover, clonal type 1 of DT104 was found to occur in sensitive as well as in a range of multiply drug-resistant variants and in a variety of plasmid profile types (in particular with small cryptic plasmids in the range of 1.0 to 5.0 Md). Since the clonal type 1 of DT104 has been identified among isolates from other countries, too, including such from the United Kingdom, the United Arab Emirates, the Philippines, and the Netherlands, its pandemic spread in man indicates that the import/export of this pathogen continues. About 5% of the DT104 isolates have been identified as genetically diverse indicating the independent appearance of the same multiple drug resistance and phage pattern phenotype among different Salmonella ancestor strains.