title: Is the production of the biogenic amines tyramine and putrescine a species-level trait in enterococci?
abstract: Biogenic amines (BA) are toxic nitrogenous compounds that can be accumulated in foods via the microbial decarboxylation of certain amino acids. Lactic acid bacteria (LAB) strains belonging to different species and genera have been described as BA producers and are mainly responsible for their synthesis in fermented foods. It is generally accepted that the capacity to produced BAs is strain-dependent. However, the large number of enterococci identified as BA producers suggests that the aminogenic trait may be a species-level characteristic. Enterococcus faecalis, Enterococcus faecium and Enterococcus durans strains of different origin were analysed to determine their capacity to produce tyramine and putrescine. The presence of the genes responsible for this and the identity of their flanking regions were checked by PCR. The results suggest that tyramine biosynthesis is a species-level characteristic in E. faecalis, E. faecium and E. durans. Putrescine synthesis was found to be a species-level trait of E. faecalis, with production occurring via the agmatine deamination pathway. Some E. faecium strains of human origin also produced putrescine; this trait was probably acquired via horizontal gene transfer.
authors.affiliation: Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Crta. de Infiesto s/n, Apdo. de Correos 85, 33300 Villaviciosa, Asturias, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Ladero
authors.forename: María
authors.initials: M
authors.lastname: Fernández
authors.forename: Marina
authors.initials: M
authors.lastname: Calles-Enríquez
authors.forename: Esther
authors.initials: E
authors.lastname: Sánchez-Llana
authors.forename: Elena
authors.initials: E
authors.lastname: Cañedo
authors.forename: M Cruz
authors.initials: MC
authors.lastname: Martín
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Alvarez
mesh_terms: D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000235:genetics / Q000378:metabolism*; D016984:Enterococcus faecium / Q000235:genetics / Q000378:metabolism*; D005516:Food Microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011700:Putrescine / Q000096:biosynthesis*; D014439:Tyramine / Q000096:biosynthesis*
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D011700:Putrescine; D014439:Tyramine