Genotypic and phenotypic properties of coagulase-negative staphylococci causing dialysis catheter-related sepsis

Sixty coagulase-negative staphylococcus (CNS) isolates were recovered from the blood cultures or peritoneal dialysate effluent of 43 patients on renal dialysis. The patients had either renal dialysis catheter-related sepsis (CRS) or continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis. Isolates were characterized by biotyping, and genotyped by pulsed-field gel electrophoresis (PFGE). Phenotypic properties of the strains were also investigated. Several genotypes were identified with no one specific strain of CNS being associated with CRS. However, closely related strains were isolated from several patients within the units studied, suggesting horizontal transfer of micro-organisms. Genotypic macro-restriction profiles did not concur with phenotypic profiles or biotypes, confirming that genotyping is required for epidemiological studies. All staphylococcal strains were investigated for the production of phenotypic characteristics. Significant differences were predominantly seen in the production of lipase, esterase and elastase in strains isolated from the renal patients with CRS and CAPD-associated peritonitis, compared with a non-septic control group. These phenotypic characteristics may therefore have a role in the maintenance of CRS in renal patients.