Evidence for a Second Genomic Island Conferring Multidrug Resistance in a Clonal Group of Strains of Salmonella enterica Serovar Typhimurium and its Monophasic Variant Circulating in Italy, Denmark, and the United Kingdom

Abstract

TEM-1 , strA-strB, sul2, and tet(B). A localization experiment demonstrated that the ASSuT resistance genes are chromosomally located. This study confirms that a multidrug-resistant clonal group, ASSuT, of S. Typhimurium and its monophasic variant has emerged and is circulating in Italy, Denmark, and the United Kingdom. Moreover, the results of this work demonstrate that the multidrug resistance in this clonal group of Salmonella strains is conferred by a new genomic island.

ECDC/EFSA/EMA first joint report on the integrated analysis of the consumption of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from humans and food-producing animals

“…Following its dissemination via the food chain, the strain was responsible for many thousands of infections in humans in affected countries, but, as with food-producing animals, antimicrobial consumption in the human population was not a major contributory factor. More recent examples include the on-going multi-country spread of a MDR "clonal complex" of a monophasic variant of S. Typhimurium exhibiting chromosomally mediated resistance to four unrelated antimicrobials, which has spread extensively in pigs in several European countries, and has also caused many human infections (EFSA, 2010;Hopkins et al, 2010;Lucarelli et al, 2010). MDR Salmonella in hospitals are rare in developed countries.…”

Chromosome-Mediated Multidrug Resistance in Salmonella enterica Serovar Typhi

“…SGI1 carries genes conferring resistance to ACSSuT and hyperinvasion capability for the SGI1-bearing Salmonella strains, S. Typhimurium DT104 in particular, which have been the most prevalent MDR Salmonella strains since the 1990s (25,26). Recently, an SGI conferring resistance to ASSuT was identified among strains of S. Typhimurium and its monophasic variant (20). This ASSuT-resistant clone soon became widespread in many European and Asia countries (27,28).…”

“…Therefore, the genomic island identified in this study was designated SGI11. In the past decades, several chromosome-mediated multidrug resistances have been identified in S. enterica (15,(18)(19)(20)(21). Salmonella strains harboring an MDR genomic island may be more virulent and have a tendency to rapidly disseminate (16,(22)(23)(24).…”

Genetic Types, Gene Repertoire, and Evolution of Isolates of the Salmonella enterica Serovar 4,5,12:i:− Spanish Clone Assigned to Different Phage Types

“…Over the last 2 decades, two major resistant clonal lines have emerged in Europe. The European clone, particularly common since 2000, harbors a chromosomal region responsible for resistance to ampicillin, streptomycin/spectinomycin, sulfonamides, and tetracycline (ASSuT type) (10,(14)(15)(16). The Spanish clone, first reported in Spain in 1997, displays plasmid-mediated resistance up to seven antimicrobial drugs: ampicillin, chloramphenicol, gentamicin, streptomycin/spectinomycin, sulfonamides, tetracyclines, and trimethoprim (ACGSSuTTp type) (3,11,17).…”