title: Antimicrobial drug resistance and genetic properties of Salmonella enterica serotype Enteritidis circulating in chicken farms in Tunisia.
abstract: This study focused on 77 isolates of Salmonella enterica serotype Enteritidis collected during 2009 to 2013 from healthy and sick chickens and environmental farm samples in Tunisia. Resistance to 14 antimicrobials and the encoding genes were analyzed. 66, 26, 6.5, 3.9 and 1.3% were pan-susceptible or showed resistance to nalidixic acid (Asp87 to Tyr and Asp87 to Asn substitutions in GyrA), ampicillin (blaTEM-1-likeand blaSHV), sulfonamides (sul1and sul3) and streptomycin (strB), respectively. A single isolate with intermediate susceptibility to ciprofloxacin was positive for qnrB, whereas qnrA, qnrS or aac(6')-Ib-cr were not detected. The virulotype of the isolates was established by testing ten virulence genes. The orgA, ssaQ, mgtC, siiD, sopB genes, located on Salmonella pathogenicity islands, and spvC of the serotype-specific virulence plasmid, were common to all isolates. In contrast, the prophage-associated sopE-1, sodC1 and gipA genes and the fimbrial bcfC gene were variably represented. All isolates except one contained the virulence plasmid, which appeared either alone or together with one or more additional plasmids. One isolate carried a single plasmid of ca. 90Kb which may be derived from the virulence plasmid (60Kb). Overall, seven resistotypes, six virulotypes and six plasmid profiles were identified. XbaI-PFGE revealed four related pulsotypes (X1-X4), with 80% of the isolates sharing the X1 pattern. The latter isolates exhibited different resistance, virulence and plasmid profiles, suggesting that mobile genetic elements, particularly prophages and plasmids, are of central importance for the evolution and adaptation of S. Enteritidis circulating in chicken farms in Tunisia.
authors.affiliation: Veterinary Research Institute of Tunisia, 20 Street Jebel Lakhdhar, Bab Saadoun, 1006 Tunis, Tunisia; Faculté des Sciences de Bizerte, Université de Carthage, Tunis, Tunisia.
authors.forename: Rakia
authors.initials: R
authors.lastname: Ben Salem
authors.affiliation: Veterinary Research Institute of Tunisia, 20 Street Jebel Lakhdhar, Bab Saadoun, 1006 Tunis, Tunisia; Faculté des Sciences de Bizerte, Université de Carthage, Tunis, Tunisia. Electronic address: salahtoumi_mohamed@yahoo.com.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Abbassi
authors.affiliation: Universidad de Oviedo, Departamento de Biología Funcional, Área de Microbiología, Julián Clavería 6, 33006 Oviedo, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: García
authors.affiliation: Universidad de Oviedo, Departamento de Biología Funcional, Área de Microbiología, Julián Clavería 6, 33006 Oviedo, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: García-Fierro
authors.affiliation: Universidad de Oviedo, Departamento de Biología Funcional, Área de Microbiología, Julián Clavería 6, 33006 Oviedo, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Fernández
authors.affiliation: Veterinary Research Institute of Tunisia, 20 Street Jebel Lakhdhar, Bab Saadoun, 1006 Tunis, Tunisia; Faculté des Sciences de Bizerte, Université de Carthage, Tunis, Tunisia.
authors.forename: Hajer
authors.initials: H
authors.lastname: Kilani
authors.affiliation: Veterinary Research Institute of Tunisia, 20 Street Jebel Lakhdhar, Bab Saadoun, 1006 Tunis, Tunisia; Faculté des Sciences de Bizerte, Université de Carthage, Tunis, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Jaouani
authors.affiliation: Regional Center of Veterinary Research, 4000 Sousse, Tunisia.
authors.forename: Monia
authors.initials: M
authors.lastname: Khayeche
authors.affiliation: National School of Veterinary Medicine, Department of Microbiology and Immunology, University of La Manouba, Tunisia.
authors.forename: Lilia
authors.initials: L
authors.lastname: Messadi
authors.affiliation: Universidad de Oviedo, Departamento de Biología Funcional, Área de Microbiología, Julián Clavería 6, 33006 Oviedo, Spain. Electronic address: rrodicio@uniovi.es.
authors.forename: María R
authors.initials: MR
authors.lastname: Rodicio
mesh_terms: D000818:Animals; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology; D002645:Chickens; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D000072480:Farms; D005838:Genotype; D058889:Molecular Typing; D010957:Plasmids / Q000032:analysis; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D014416:Tunisia / Q000453:epidemiology; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D037521:Virulence Factors
keywords: Antimicrobial drug resistance; PFGE; Poultry; Virulence genes; qnrB