Clinical and epidemiological significance of species identification of coagulase-negative staphylococci in a microbiological laboratory.

Although coagulase-negative staphylococci have been implicated in certain human infections, they are generally regarded as contaminants and their clinical significance has been questioned. To assess their role as pathogens, we studied 203 isolates of coagulase-negative staphylococci cultured from blood, wounds, body fluids (pleural, peritoneal and cerebrospinal), urine, and catheter tips. Patients' charts were reviewed and the clinical significance of these isolates was determined. Staphylococcus epidermidis accounted for 48% of isolates, S. hemolyticus for 33%, and other species (including S. capitis, S. hominis, S. warneri, S. cohnii, S. simulans, S. xylosus and S. saprophyticus) for the remaining 19%. There was no correlation between the pathogenicity and the species isolated, the source it was isolated from, or the pattern of antibiotic susceptibility. These observations suggest that identification of coagulase-negative staphylococcal species may be of limited value in predicting clinical significance.