title: Co-occurrence of ACSSuT and cephalosporin resistance phenotypes is mediated by int1-associated elements in nontyphoidal Salmonella enterica from human infections in Spain.
abstract: A screening of antimicrobial resistance and its genetic determinants has been performed on 300 Salmonella enterica isolates collected during 2004-2008 from human infections in Spain. Salmonella Typhimurium and Salmonella Enteritidis were the major serotypes, which were found with similar frequencies covering 80% of the bacterial collection. Salmonella Typhimurium isolates frequently shared low susceptibility to antimicrobials of the penta-resistance phenotype (ACSSuT) and/or cephalosporin resistance. The ACSSuT profile was found closely linked to int1-associated gene cassettes, with major elements carrying DNA fragments of 1.0 Kb (aadA2 gene) plus 1.2 Kb (blaPSE-1 gene) or 2.0 Kb (aadA1 and blaOXA-1 genes). Among these, ACSSuT and cephalosporin resistances were associated in Salmonella Typhimurium isolates expressing the blaOXA gene. β-lactamase activities were also detected from isolates carrying blaTEM, blaCMY, or blaSHV, although only the two last genes expressed extended-spectrum β-lactamases. The clonal analysis of S. enterica strains suggests that both horizontal and vertical transfer mechanisms are involved in the wide dissemination of their antimicrobial resistance.
authors.affiliation: 1 Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de Extremadura , Cáceres, Spain .
authors.forename: Maria Jorge
authors.initials: MJ
authors.lastname: Campos
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Palomo
authors.forename: Lorena
authors.initials: L
authors.lastname: Hormeño
authors.forename: María
authors.initials: M
authors.lastname: Ugarte
authors.forename: María Concepción
authors.initials: MC
authors.lastname: Porrero
authors.forename: Silvia
authors.initials: S
authors.lastname: Herrera-León
authors.forename: Santiago
authors.initials: S
authors.lastname: Vadillo
authors.forename: Segundo
authors.initials: S
authors.lastname: Píriz
authors.forename: Alberto
authors.initials: A
authors.lastname: Quesada
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D018550:Cephalosporin Resistance / Q000187:drug effects / Q000235:genetics*; D002511:Cephalosporins / Q000627:therapeutic use; D003227:Conjugation, Genetic; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006801:Humans; D012480:Salmonella Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D012703:Serotyping; D013030:Spain / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases