The genomic diversity of coagulase-negative staphylococci associated with nosocomial infections.

A total of 117 isolates of coagulase-negative staphylococci (CNS) were collected from patients in three medical centres. They were genotyped by pulsed-field gel electrophoresis (PFGE) following digestion with restriction enzymes SmaI and SstII. The isolates included Staphylococcus epidermidis, S. simulans, S. hominis, S. lugdunensis, S. capitis, S. saprophyticus, S. caprae and S. sciuri. They were collected at random from 82 patients and were associated with infected central venous lines, continuous ambulatory peritoneal dialysis (CAPD) catheters, endocarditis, osteomyelitis of prosthetic hips and internally fixed fractures. The genetic heterogeneity of the strains was demonstrated by PFGE profiles and two dendrograms. Though the strains were segregated into species, there was no clustering of the strains by type of infection, associated medical unit or geographical location of the patient. Numerous genotypes were identified, suggesting that no specific strains of CNS are associated with prosthetic related infection.