title: Antimicrobial susceptibility of Salmonella enterica isolates from healthy breeder and broiler flocks in Portugal.
abstract: Three hundred and thirty-three isolates representing 40 different serotypes of Salmonella enterica, recovered from environmental and faecal samples of breeder and broiler flocks from 2009 to 2011, were studied. Antimicrobial susceptibility was determined by measuring the minimal inhibitory concentration of 11 antimicrobials using the agar dilution method. Salmonella Havana, S. Enteritidis and S. Mbandaka were the most common serotypes isolated from broiler flocks, while S. Enteritidis was the common isolate from breeder flocks. The frequency of non-wild-type Salmonella isolates (those with decreased susceptibility to the different antimicrobials) varied according to serotype. S. Mbandaka in broilers and S. Enteritidis in both breeders and broilers showed higher frequencies of reduced susceptibility to quinolones, but clinical resistance towards ciprofloxacin was not observed. Reduced susceptibility to sulfamethoxazole, tetracycline, ampicillin and streptomycin were common in Salmonella Typhimurium isolates. Two isolates of S. Havana from broilers were resistant to cefotaxime and phenotypically categorised as extended-spectrum β-lactamase producers. The results presented in this study provide useful data on the antimicrobial susceptibility of different Salmonella serotypes and highlight the high diversity of multi-drug resistance patterns present.
authors.affiliation: INIAV - National Institute for Agrarian and Veterinary Research, Estrada de Benfica, 701, 1549-011 Lisboa, Portugal. Electronic address: lurdes.clemente@iniav.pt.
authors.forename: Lurdes
authors.initials: L
authors.lastname: Clemente
authors.affiliation: INIAV - National Institute for Agrarian and Veterinary Research, Estrada de Benfica, 701, 1549-011 Lisboa, Portugal.
authors.forename: Ivone
authors.initials: I
authors.lastname: Correia
authors.affiliation: INIAV - National Institute for Agrarian and Veterinary Research, Estrada de Benfica, 701, 1549-011 Lisboa, Portugal.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Themudo
authors.affiliation: Faculty of Veterinary Science, Technical University of Lisbon, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Neto
authors.affiliation: National Reference Laboratory of Antimicrobial Resistance, Department of Infectious Diseases, National Institute of Health Dr Ricardo Jorge, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Centre for the Study of Animal Sciences (ICETA), University of Oporto, Rua D. Manuel II, Apartado 55412, 4051-401 Oporto, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Caniça
authors.affiliation: Faculty of Veterinary Science, Technical University of Lisbon, Av. da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Fernando
authors.initials: F
authors.lastname: Bernardo
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D008826:Microbial Sensitivity Tests / Q000662:veterinary*; D011174:Portugal / Q000453:epidemiology; D011201:Poultry Diseases / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology; D019779:Salmonella enterica / Q000187:drug effects*; D012477:Salmonella enteritidis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antimicrobial susceptibility; Breeders; Broilers; Salmonella enterica