title: Biocide Tolerance and Antibiotic Resistance in Salmonella Isolates from Hen Eggshells.
abstract: The aim of the present study was to determine biocide tolerance and antibiotic resistance in Salmonella isolates from hen eggshells. A total of 39 isolates from hen eggshells, identified as either Salmonella spp. or Salmonella enterica according to 16S rDNA sequencing, were selected for biocide tolerance. Isolates with minimum inhibitory concentrations (MICs) above the wild-type MICs were considered to be biocide tolerant: benzalkonium chloride (BC, 7.7%), cetrimide (CT, 7.7%), hexadecylpyridinium chloride (HDP, 10.3%), triclosan (TC, 17.9%), hexachlorophene (CF, 30.8%), and P3-oxonia (OX, 25.6%). The resulting 21 biocide-tolerant isolates were further characterized. Most isolates (95.2%) were resistant to ampicillin, but only 9.5% were resistant to cefotaxime as well as to ceftazidime. Resistance to chloramphenicol (61.9%), tetracycline (47.6%), streptomycin (19.0%), nalidixic acid (28.6%), ciprofloxacin (9.5%), netilmicin (14.3%), and trimethoprim-sulfamethoxazole (38.1%) was also detected. Considering only antibiotics, 66.7% of isolates were multiresistant; furthermore, 90.5% were multiresistant considering antibiotics and biocides combined. Efflux pump and biocide tolerance genetic determinants detected included acrB (95.2%), oqxA (14.3%), mdfA (9.5%), qacA/B (4.8%), and qacE (9.5%). Antibiotic resistance genes detected included blaTEM(14.3%), blaCTXM-2(4.8%), blaPSE(4.8%), floR (19.05%), tet(A) (9.5%), tet(C) (4.8%), dfrA12 (0.05%), and dfrA15 (0.05%). Significant positive correlations were detected between phenotypic tolerance/resistance to biocides, biocides and antibiotics, and also between antibiotics, suggesting that a generalized use of biocides could co-select antibiotic resistance.
authors.affiliation: Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén, Spain .
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Fernández Márquez
authors.affiliation: Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén, Spain .
authors.forename: María José Grande
authors.initials: MJ
authors.lastname: Burgos
authors.affiliation: Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén, Spain .
authors.forename: Rubén Pérez
authors.initials: RP
authors.lastname: Pulido
authors.affiliation: Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén, Spain .
authors.forename: Antonio
authors.initials: A
authors.lastname: Gálvez
authors.affiliation: Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén, Spain .
authors.forename: Rosario Lucas
authors.initials: RL
authors.lastname: López
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001548:Benzalkonium Compounds / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D002645:Chickens; D002701:Chloramphenicol / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D004202:Disinfectants / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D004528:Egg Shell / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology; D012475:Salmonella / Q000187:drug effects* / Q000302:isolation & purification*; D019779:Salmonella enterica / Q000187:drug effects / Q000302:isolation & purification; D013307:Streptomycin / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001548:Benzalkonium Compounds; D004202:Disinfectants; D009268:Nalidixic Acid; D002939:Ciprofloxacin; D002701:Chloramphenicol; D002442:Ceftazidime; D013752:Tetracycline; D013307:Streptomycin
keywords: Salmonella; antimicrobial resistance; biocide tolerance; eggshells