Staphylococcus epidermidis is a biofilm-producing organism found ubiquitously on human skin and mucous membranes.  This organism may cause hospital acquired and opportunistic infections in susceptible hosts.  High dependency patients routinely require indwelling medical devices which may become colonised with S. epidermidis.  These colonised devices provide a portal for bacteria to enter the bloodstream and under certain circumstances, cause clinically significant bloodstream infections.  Alternatively, growth of this bacterium from patient blood cultures may indicate contamination during initial blood collection.  Consequently, isolation of S. epidermidis from blood cultures obtained from high dependency patients presents a quandary for patient management.

This study will present findings following   the examination of S. epidermidis housekeeping genes for polymorphisms that will facilitate the identification of genotypes that may have increased propensities to cause bacteraemia.  Molecular interrogation was performed on 160 strains of S. epidermidis isolated from patient blood cultures using novel Single Nucleotide Polymorphism methods.  Results demonstrating clonal relationships between strains isolated from three high dependency units and over an eight year period will be presented.  Furthermore, the association of clones with pathogenicity with respect to the study isolates will be explored.