title: Resistance phenotypes and genotypes of Salmonella enterica subsp. enterica isolates from feed, pigs, and carcasses in Brazil.
abstract: Salmonella enterica subsp. enterica plays a role as a foodborne pathogen worldwide. The consumption of contaminated pork has been associated with human salmonellosis and the increase in antimicrobial resistance among Salmonella from pigs and pork products is a concern. A total of 225 Salmonella isolates from feed mills, the lairage environment, and the intestinal contents of pigs and carcasses were investigated for their antimicrobial susceptibility. A MIC for ciprofloxacin was screened by agar dilution, and antimicrobial resistance genes were investigated by PCR assays. Among the tested isolates, 171 (76%) showed resistance to at least one antimicrobial agent, and 91 (40.4%) were multiresistant. Resistance occurred most frequently to tetracycline (54.5%), sulfonamides (39.6%), and streptomycin (33.7%). Thirty-two (94.1%) nalidixic acid-resistant isolates exhibited decreased susceptibility to ciprofloxacin. The resistance genes found were blaTEM (ampicillin), tet(A) (tetracycline), tet(B) (tetracycline/minocycline), sul1, sul2, and sul3 (sulfonamides), catA1 (chloramphenicol), floR (florfenicol/chloramphenicol), strA and strB (streptomycin), aph(3')-Ia (kanamycin), aac(3)-IIa and aac(3)-IVa (apramycin/gentamicin), aadA variant (streptomycin/spectinomycin), and dfrA1 (trimethoprim). Salmonella isolates from pig feces and carcasses displayed a higher frequency of resistance to most antimicrobials tested than isolates from feed mills. Common resistance gene profiles were found in isolates from the lairage and the intestinal content of pigs and carcasses, demonstrating that resistance genes selected on farms may be found in pork.
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 90540-000.
authors.forename: Graciela Volz
authors.initials: GV
authors.lastname: Lopes
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 90540-000.
authors.forename: Caroline
authors.initials: C
authors.lastname: Pissetti
authors.affiliation: Faculdade de Medicina Veterinária, Universidade Federal do Pampa, Campus Uruguaiana, Brazil 97500-970.
authors.forename: Débora
authors.initials: D
authors.lastname: da Cruz Payão Pellegrini
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 90540-000.
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: da Silva
authors.affiliation: Departamento de Medicina Veterinária Preventiva, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 90540-000. mcardoso@ufrgs.br.
authors.forename: Marisa
authors.initials: M
authors.lastname: Cardoso
mesh_terms: D000821:Animal Feed / Q000032:analysis / Q000382:microbiology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001938:Brazil; D003257:Consumer Product Safety; D024901:Drug Resistance, Multiple, Bacterial; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents