title: Occurrence of extended-spectrum β-lactamases among isolates of Salmonella enterica subsp. enterica from food-producing animals and food products, in Portugal.
abstract: A total of 1120 Salmonella spp. isolates, recovered from poultry, swine and food products of animal origin (bovine, swine and poultry) over the period of 2009-2011, were investigated in order to determine their serotype, susceptibility to a panel of eleven antimicrobials (A, ampicillin; Ct, cefotaxime; Cp, ciprofloxacin; Tm, trimethoprim; Su, sulfamethoxazole; C, chloramphenicol; S, streptomycin; G, gentamicin; T, tetracycline; NA, nalidixic acid; Fl, florfenicol), and the presence of resistance determinants of extended-spectrum cephalosporins. Overall, Salmonella Enteritidis was the most common serotype in all three animal species. In 618 isolates of poultry, 32.8% comprised S. Enteritidis, 18.3% Salmonella Havana and 16.5% Salmonella Mbandaka; in 101 isolates of pigs, 21.8% comprised Salmonella Rissen and Salmonella Typhimurium, 10.9% Salmonella Derby and Salmonella London. Salmonella I 4,[5],12:i:- was the most common serotype recovered from pork and beef food products comprising 32.6% and 30% of isolates respectively, followed by S. Rissen (26% and 24%) and S. Typhimurium (18.2% and 19%), respectively. In poultry products, S. Enteritidis was the most frequent serotype (62.7%), followed by S. Mbandaka (10.2%) and S. Derby (8.5%). Susceptibility profiles differed according to the origin of the isolates. Five multidrug resistant isolates (0.45%) were further characterized as extended-spectrum β-lactamase (ESBL) producers. Polymerase chain reaction and sequencing of the amplicons confirmed the presence of bla(CTX-M-1) (n = 2), bla(CTX-M-14) (n = 1), bla(CTX-M-15) (n = 1) and bla(CTX-M-32) (n = 1); bla(SHV-12) and bla(TEM-1) genes were also detected in two isolates of S. I 4,[5],12:i:-. Four isolates, two S. Havana and two S. I 4,[5],12:i:-, carried class 1 integrons and in three, two S. I 4,[5],12:i:- and one S. Havana, ISEcp1 was identified associated to bla(CTX-M-1), bla(CTX-M-32) and bla(CTX-M-14) genes. Additionally, in one S. I 4,[5],12:i:- isolate, orf477 was identified linked to bla(CTX-M-32). No plasmid mediated quinolone resistance-encoding genes were detected. Here, we report for the first time the presence of bla(CTX-M) genes in Salmonella enterica subsp enterica isolates recovered from poultry and food products of swine origin, in Portugal.
authors.affiliation: INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Estrada de Benfica, 701, 1549-011 Lisboa, Portugal.
authors.forename: Lurdes
authors.initials: L
authors.lastname: Clemente
authors.forename: Vera
authors.initials: V
authors.lastname: Manageiro
authors.forename: Eugénia
authors.initials: E
authors.lastname: Ferreira
authors.forename: Daniela
authors.initials: D
authors.lastname: Jones-Dias
authors.forename: Ivone
authors.initials: I
authors.lastname: Correia
authors.forename: Patrícia
authors.initials: P
authors.lastname: Themudo
authors.forename: Teresa
authors.initials: T
authors.lastname: Albuquerque
authors.forename: Manuela
authors.initials: M
authors.lastname: Caniça
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D002417:Cattle; D018550:Cephalosporin Resistance; D024901:Drug Resistance, Multiple, Bacterial; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011174:Portugal; D011200:Poultry; D019779:Salmonella enterica / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D012703:Serotyping; D013552:Swine; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases
keywords: CTX-M group; ESBL; Food-producing animals; Multidrug resistance; Salmonella enterica