Seven merA alleles are spread among enterococci from diferent species, environments and clonal backgrounds (1926-2012)

FEMS-2221 Metals and microbes SEVEN MERA ALLELES ARE SPREAD AMONG ENTEROCOCCUS FROM DIFERENT SPECIES, ENVIRONMENTS AND CLONAL BACKGROUNDS (1926- 2012) A. Sanchez-Valenzuela1, E. Silveira2, A.R. Freitas2, P. Antunes3, F. Baquero4, T.M. Coque4, L. Peixe2, C. Novais2 1Microbiologia, Ramón y Cajal Hospital, Madrid, Portugal 2Faculdade de Farmácia., UCIBIO/REQUIMTE. Universidade do Porto, Porto, Portugal 3Faculdade de Farmácia/Faculdade de Ciências da Nutrição e Alimentação., UCIBIO/REQUIMTE. Universidade do Porto, Porto, Portugal 4Microbiologia, Ramón y Cajal Hospital, Madrid, Spain Background Successful bacteria accumulated different genetic features shaping their evolution and fitness to diverse environments/hosts. Mercury (Hg) is widespread in Nature and possibly contributed for selection of particular strains. Objectives To evaluate the dispersion of diverse merA alleles among enterococci from several origins and clonal backgrounds. Methods merA alleles was searched in Enterococcus available genomes, used to construct a maximum-likelihood phylogenetic tree. A PCR scheme+RFLP+sequencing was developed to detect the six merA alleles identified, namely I-(GenBank- AECE01000068), IIA-(AIUL01000023.1), IIB-(ASDU01000008.1), III- (NZ_KB947199.1), IV-(AECE01000068.1) and VI-(NZ_KB030055.1), among 918 Enterococcus (Portugal; human/animal/environment/food; 1996-2012). Clonality was evaluated by PFGE/MLST, merA-transfer by conjugation and Hg-phenotype in m_Enterococcus+128mg/L HgCl2. Conclusions merA were found in 4% (n=37/918) of Enterococcus studied. PCR+RFLP+sequencing distinguished the six alleles previously found at Genbank and a new one (type V). They were distributed among diverse sources and clones, in our and GenBank isolates: types I and IV-human E. faecalis (Efls; n=5; USA; 1987- 88; ST9/ST206); IIA-human/pig/trout/feed/hospital-sewage E. faecium- Efm/E.hirae/Enterococcus_sp (n=17/1/1; Portugal/France/Denmark/Germany; 1989- 2012; 12ST-Efm including from ST78-ST17-ST18-lineages-CC17); IIB-human Efls/E.dispar (n=2/1; Portugal/USA; 1926-2001; ST206/ST105/ST107); III- human/animal/hospital-sewage Efls/E.casseliflavus (n=15/1; Portugal/France/USA/Canada/Japan; 1961-2012; ST64/ST9/ST30/ST159/ST245); V- human/trout/pig-manure Efm (n=4; Portugal; 2001-2006; ST94/ST890); VI- human/hospital-sewage/piggery-soil/piggery-manure/trout Efm (n=23; Portugal, Italy France, Germany, Denmark, Hungary, Switzerland, Ireland, Norway, Brazil, USA; 1961-2012; 14ST including ST78-ST17-ST18-lineages-CC17). The presence of merA among major Efm/ST9-Efls lineages associated with human infections, suggests that mercurial-compounds potentially contributed for their selection/maintenance. merA+- Enterococcus grown in >128mg/L-HgCl2. Transfer occurred for IIA and VI alleles. All but VI-merA alleles, were also identified in genomes of different species of Firmicutes (data not shown), suggesting genetic exchange of enterococci with bacteria sharing the same communities/environmental challenges.