Staphylococcal cassette chromosome mec (SCCmec) and arginine catabolic mobile element (ACME) in Staphylococcus epidermidis isolated from prosthetic joint infections

The aim of the present study was to characterise the staphylococcal cassette chromosome mec (SCCmec) in Staphylococcus epidermidis isolated from prosthetic joint infections (PJIs) and, if possible, assign them to any of the presently known SCCmec types. In addition, the isolates were examined for the presence of the arginine catabolic mobile element (ACME). Sixty-one S. epidermidis isolates obtained from PJIs and 24 commensal S. epidermidis isolates were analysed. The mecA gene was detected in 49 of the 61 (80 %) PJI isolates and in four of the 24 (17 %) commensal isolates, and the composition of the SCCmec was further analysed. SCCmec types I and IV were the most common types among the PJI isolates. However, for over half (57 %) of the isolates, it was not possible to assign an SCCmec type. ACME was detected in eight (13 %) of the PJI isolates and in 14 (58 %) of the commensal isolates. The characterisation of the SCCmec elements revealed a large heterogeneity, with a high frequency of isolates carrying more than one type of the ccr gene complex. ACME was more common among the commensal isolates and may represent a survival benefit for S. epidermidis colonising healthy individuals in the community.