Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.18/4431
Título: Tolerance to multiple metal stressors in emerging non-typhoidal MDR Salmonella serotypes: a relevant role for copper in anaerobic conditions
Autor: Mourão, Joana
Marçal, Sara
Ramos, Paula
Campos, Joana
Machado, Jorge
Peixe, Luísa
Novais, Carla
Antunes, Patrícia
Palavras-chave: Salmonella
Infecções Gastrointestinais
Data: Ago-2016
Editora: Oxford University Press/British Society for Antimicrobial Chemotherapy
Citação: J Antimicrob Chemother. 2016 Aug;71(8):2147-57. doi: 10.1093/jac/dkw120. Epub 2016 Apr 26.
Resumo: Objectives: Factors driving the expansion of particular MDR Salmonella serotypes/clones are not completely understood. We assessed if emergent MDR Salmonella serotypes/clones were more enriched in metal tolerance genes (e.g. to Cu/Ag) than other less frequent ones, as an additional feature to survive in environments contaminated with metals. Methods: Metal (Cu pco/Ag,Cu sil/Hg mer/As ars/Te ter) tolerance genes screening (PCR/sequencing), MICs of CuSO4/AgNO3 (aerobiosis/anaerobiosis), genetic element characterization (S1/I-CeuI PFGE) and conjugation assays were performed in a well-characterized Salmonella collection (n = 275 isolates; 2000–14; 49 serotypes/clones). Results The sil ± pco genes were detected in 37% of isolates from diverse serotypes, mainly in emergent Rissen/ST469 and Typhimurium/ST34 European clone (100%), which are mostly associated with pig settings where Cu is highly used. These genes were frequently co-located with merA ± terF and/or antibiotic resistance genes in plasmids (100–270 kb; IncHI2/IncHI1/IncN/IncFIIA; mostly transferable by conjugation) or in the chromosome. Most sil ± pco+ isolates (77%) were MDR contrasting with sil ± pco− ones (48%). The sil ± pco+ isolates presented significantly higher MICCuSO4 under anaerobiosis (MIC50/MIC90 = 28/32 mM) and MICAgNO3 after previous Ag contact (MIC50/MIC90 > 3 mM) than sil− ones (MIC50/MIC90 = 2/8 mM to CuSO4; MIC50/MIC90 = 0.125/0.16 mM to AgNO3). Use of these modified methodological approaches allowed the establishment of CuSO4/AgNO3 tolerance cut-offs to differentiate sil+ and sil− isolates, here firstly proposed. Conclusions: This study demonstrates that acquisition of Cu/Ag tolerance genes (sil/pco genes) might contribute to the emergence of particular clinically relevant MDR Salmonella serotypes/clones by facilitating their survival in diverse metal-contaminated settings, particularly in pig production. Assessment of control measures for the use and/or accumulation of metals in diverse environments are needed to prevent a wider expansion of such strains or the emergence of new ones.
Peer review: yes
URI: http://hdl.handle.net/10400.18/4431
DOI: 10.1093/jac/dkw120
ISSN: 0305-7453
Versão do Editor: https://academic.oup.com/jac/article-abstract/71/8/2147/2238170/Tolerance-to-multiple-metal-stressors-in-emerging?redirectedFrom=fulltext
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