title: Antimicrobial resistance and virulence determinants in European Salmonella genomic island 1-positive Salmonella enterica isolates from different origins.
abstract: Salmonella genomic island 1 (SGI1) contains a multidrug resistance region conferring the ampicillin-chloramphenicol-streptomycin-sulfamethoxazole-tetracycline resistance phenotype encoded by bla(PSE-1), floR, aadA2, sul1, and tet(G). Its increasing spread via interbacterial transfer and the emergence of new variants are important public health concerns. We investigated the molecular properties of SGI1-carrying Salmonella enterica serovars selected from a European strain collection. A total of 38 strains belonging to S. enterica serovar Agona, S. enterica serovar Albany, S. enterica serovar Derby, S. enterica serovar Kentucky, S. enterica serovar Newport, S. enterica serovar Paratyphi B dT+, and S. enterica serovar Typhimurium, isolated between 2002 and 2006 in eight European countries from humans, animals, and food, were subjected to antimicrobial susceptibility testing, molecular typing methods (XbaI pulsed-field gel electrophoresis [PFGE], plasmid analysis, and multilocus variable-number tandem-repeat analysis [MLVA]), as well as detection of resistance and virulence determinants (PCR/sequencing and DNA microarray analysis). Typing experiments revealed wide heterogeneity inside the strain collection and even within serovars. PFGE analysis distinguished a total of 26 different patterns. In contrast, the characterization of the phenotypic and genotypic antimicrobial resistance revealed serovar-specific features. Apart from the classical SGI1 organization found in 61% of the strains, seven different variants were identified with antimicrobial resistance properties associated with SGI1-A (S. Derby), SGI1-C (S. Derby), SGI1-F (S. Albany), SGI1-L (S. Newport), SGI1-K (S. Kentucky), SGI1-M (S. Typhimurium), and, eventually, a novel variant similar to SGI1-C with additional gentamicin resistance encoded by aadB. Only minor serovar-specific differences among virulence patterns were detected. In conclusion, the SGI1 carriers exhibited pathogenetic backgrounds comparable to the ones published for susceptible isolates. However, because of their multidrug resistance, they may be more relevant in clinical settings.
authors.affiliation: Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Berlin, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Beutlich
authors.forename: Silke
authors.initials: S
authors.lastname: Jahn
authors.forename: Burkhard
authors.initials: B
authors.lastname: Malorny
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hauser
authors.forename: Stephan
authors.initials: S
authors.lastname: Hühn
authors.forename: Andreas
authors.initials: A
authors.lastname: Schroeter
authors.forename: Maria Rosario
authors.initials: MR
authors.lastname: Rodicio
authors.forename: Bernd
authors.initials: B
authors.lastname: Appel
authors.forename: John
authors.initials: J
authors.lastname: Threlfall
authors.forename: Dik
authors.initials: D
authors.lastname: Mevius
authors.forename: Reiner
authors.initials: R
authors.lastname: Helmuth
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D002874:Chromosome Mapping; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005060:Europe; D005516:Food Microbiology; D005798:Genes, Bacterial; D044404:Genomic Islands; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D013045:Species Specificity; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D037521:Virulence Factors