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pubmed:abstractText |
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 (E1162?intA) was constructed and in trans complemented with wild-type intA (E1162?intA::pEF30). Circular intermediates (CI) of excised esp PAI were determined using inverse PCR analysis on purified chromosomal DNA from strains E1162, E1162?esp, E1162?intA, and E1162?intA::pEF30. In E1162 and E1162?esp, CI of the esp PAI were detected. No CI were detected in E1162?intA, while in the complemented strain E1162?intA::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.
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