title: Phylogenetic analysis of vancomycin-resistant Enterococcus faecium genotypes associated with outbreaks or sporadic infections in Italy.
abstract: Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to investigate the genetic relatedness of a total of 41 Enterococcus faecium isolates from different backgrounds (hospital outbreaks, n = 9; documented sporadic infections, n = 10; asymptomatic sporadic carriage of hospitalized patients, n = 9; healthy persons, n = 3; non-human sources, n = 10) over the period 1996-2004 in comparison with clones that have spread in Italy since 1993. Thirty six isolates were vancomycin-resistant and five were vancomycin-susceptible. eBURST analysis of MLST sequence types generated two groups: (1) group 1 (27 isolates) forming a clonal complex (CC17) with the predicted founder corresponding to ST17, a genotype identified in 1994, that included esp-positive and -negative clones isolated from hospitalized patients; and (2) group 2 (14 isolates) including esp-negative clones from different sources (hospitalized patients, healthy persons and non-human sources). The hyl gene was found in five strains with different PFGE types, all belonging to group 1, whereas cylA, gelE, and asa1, were not detected in any of the isolates. Our data showed that the evolution of the MLST C1 epidemic lineage has been continuing in several Italian areas and generating new clones with different PFGE patterns. The main, though not the sole, mechanism that has driven this evolution was confirmed to be linked to the presence of the esp gene.
authors.affiliation: Microbiology Section, Department of Pathology, University of Verona, Verona, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bonora
authors.forename: Debora
authors.initials: D
authors.lastname: Olioso
authors.forename: Giuliana
authors.initials: G
authors.lastname: Lo Cascio
authors.forename: Roberta
authors.initials: R
authors.lastname: Fontana
mesh_terms: D000081:Acetamides / Q000494:pharmacology; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D004269:DNA, Bacterial; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D005838:Genotype; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D000069349:Linezolid; D023303:Oxazolidinones / Q000494:pharmacology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D020713:Vancomycin Resistance / Q000235:genetics*; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000081:Acetamides; D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D023303:Oxazolidinones; D037521:Virulence Factors; D000069349:Linezolid