title: The recombinase IntA is required for excision of esp-containing ICEEfm1 in Enterococcus faecium.
abstract: Comparative genome analysis of Enterococcus faecium recently revealed that a genomic island containing the esp gene, referred to as the esp-containing pathogenicity island (esp PAI), can be transferred by conjugation and contains a partial Tn916-like element and an integrase gene, intA. Here, we characterize the role of intA in the excision of the esp PAI. An intA insertion-deletion mutant in E. faecium E1162 (E1162ΔintA) was constructed and in trans complemented with wild-type intA (E1162ΔintA::pEF30). Circular intermediates (CI) of excised esp PAI were determined using inverse PCR analysis on purified chromosomal DNA from strains E1162, E1162Δesp, E1162ΔintA, and E1162ΔintA::pEF30. In E1162 and E1162Δesp, CI of the esp PAI were detected. No CI were detected in E1162ΔintA, while in the complemented strain E1162ΔintA::pEF30 CI formation was restored, indicating that intA is essential for excision and subsequent mobilization of the esp-containing genomic island in E. faecium. Based on the fact that this island can be mobilized and is self-transmissible, we propose to change the name of the esp PAI to ICEEfm1.
authors.affiliation: Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, Netherlands. j.top@umcutrecht.nl
authors.forename: Janetta
authors.initials: J
authors.lastname: Top
authors.forename: Jan C
authors.initials: JC
authors.lastname: Sinnige
authors.forename: Eline A M
authors.initials: EA
authors.lastname: Majoor
authors.forename: Marc J M
authors.initials: MJ
authors.lastname: Bonten
authors.forename: Rob J L
authors.initials: RJ
authors.lastname: Willems
authors.forename: Willem
authors.initials: W
authors.lastname: van Schaik
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D016984:Enterococcus faecium / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D044404:Genomic Islands; D019426:Integrases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D019426:Integrases