title: Antimicrobial Resistance Profiles of Listeria monocytogenes and Listeria innocua Isolated from Ready-to-Eat Products of Animal Origin in Spain.
abstract: The objective of this work was to investigate the antimicrobial resistance in Listeria spp. isolated from food of animal origin. A total of 50 Listeria strains isolated from meat and dairy products, consisting of 7 Listeria monocytogenes and 43 Listeria innocua strains, were characterized for antimicrobial susceptibility against nine antimicrobials. The strains were screened by real-time PCR for the presence of antimicrobial resistance genes: tet M, tet L, mef A, msr A, erm A, erm B, lnu A, and lnu B. Multidrug resistance was identified in 27 Listeria strains, 4 belonging to L. monocytogenes. Resistance to clindamycin was the most common resistance phenotype and was identified in 45 Listeria strains; the mechanisms of resistance are still unknown. A medium prevalence of resistance to tetracycline (15 and 9 resistant and intermediate strains) and ciprofloxacin (13 resistant strains) was also found. Tet M was detected in Listeria strains with reduced susceptibility to tetracycline, providing evidence that both L. innocua and L. monocytogenes displayed acquired resistance. The presence of antimicrobial resistance genes in L. innocua and L. monocytogenes indicates that these genes may be transferred to commensal and pathogenic bacteria via the food chain; besides this, antibiotic resistance in L. monocytogenes could compromise the effective treatment of listeriosis in humans.
authors.affiliation: Department of Animal Production and Food Science, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza-CITA , Zaragoza, Spain .
authors.forename: Cristina
authors.initials: C
authors.lastname: Escolar
authors.affiliation: Department of Animal Production and Food Science, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza-CITA , Zaragoza, Spain .
authors.forename: Diego
authors.initials: D
authors.lastname: Gómez
authors.affiliation: Department of Animal Production and Food Science, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza-CITA , Zaragoza, Spain .
authors.forename: María
authors.initials: M
authors.lastname: Del Carmen Rota García
authors.affiliation: Department of Animal Production and Food Science, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza-CITA , Zaragoza, Spain .
authors.forename: Pilar
authors.initials: P
authors.lastname: Conchello
authors.affiliation: Department of Animal Production and Food Science, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2), Universidad de Zaragoza-CITA , Zaragoza, Spain .
authors.forename: Antonio
authors.initials: A
authors.lastname: Herrera
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004269:DNA, Bacterial / Q000302:isolation & purification; D003611:Dairy Products / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D057140:Fast Foods / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005798:Genes, Bacterial; D008087:Listeria / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D008461:Meat Products / Q000382:microbiology; D015203:Reproducibility of Results; D013030:Spain; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D013752:Tetracycline
keywords: Listeria innocua; Listeria monocytogenes; antimicrobial resistance; genetic determinants; ready-to-eat products