Is hospital-acquired intravascular catheter-related sepsis associated with outbreak strains of coagulase-negative staphylococci?

Macrorestriction fragment profile analysis by pulsed field gel electrophoresis was used to type strains of coagulase-negative staphylococci (CNS) isolated from 30 patients with catheter-related sepsis at the University Hospital Birmingham NHS Trust, UK. Twenty-three infections were hospital-acquired. A total of 56 CNS were isolated from the patients and identified by API as Staphylococcus epidermidis (54), Staphylococcus lugdunensis (1) and Staphylococcus hominis (1). The micro-organisms were further characterized by antibiograms and restriction digestion using SmaI. Analysis of the macrorestriction fragment profiles demonstrated that the isolates from 24 patients were distinct, whereas a common genotype of S. epidermidis was isolated from the blood cultures of six patients, all of whom had acquired this infection in hospital. Three of these patients were located in a haematology ward, two on an intensive care unit and one on a dialysis unit. The data from this current study suggests that specific strains of S. epidermidis may be an important cause of nosocomial catheter-related sepsis resulting from cross-infection, and that this association would not be detected by conventional typing methods including biotyping and antibiograms.