Genomic Islands

Three novel genomic islands have been identified in S. epidermidis [17] (Fig. 9.2). The vSe1 and vSe2 islands originate from integrated plasmids. vSe1 was detected in RP62A and comprises 17153 nucleotides. A striking feature of vSe1 is an encoded cadmium resistance protein (CadD) and its corresponding transcription regulator (CadC). S. epidermidis ATCC1228 lacks vSe1, but carries instead a single 4455-kb ORF of unknown function at the same integration site (SE2204 in Fig. 9.2). vSe2 was identified by Gill and coworkers in ATCC 12228 [17]. It is a relatively large structure, 38.4 kbp in size, and encodes a range of interesting traits which are unique to this strain and have not been found in other staphylococci so far. The island carries an additional sortase gene (srtC) and genes coding for two LPXTG-anchored cell wall proteins, implying specific interactions of this strain with host structures. The third island, vSey, is present in both S. epidermidis genomes at the same site. The small 2.66-kb islet encodes a putative phosphoesterase, a hydrolase, and four ยก51 phenol-soluble modulins which have been shown recently to be involved in activation of the human innate immune system [103].

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