Clinical importance of identifying coagulase-negative staphylococci isolated from blood cultures: evaluation of MicroScan Rapid and Dried Overnight Gram-Positive panels versus a conventional reference method.

Journal Article (Journal Article)

We evaluated the clinical usefulness of species identification of blood isolates of coagulase-negative staphylococci as a predictor of the clinical significance of the isolates. In addition, we compared results of species identification obtained with MicroScan Rapid Gram-Positive Identification panels and Dried Overnight (Conventional) Gram-Positive Identification panels with those obtained by a tube reference method. Two hundred eighty-five blood isolates were tested, including 92 judged to represent true bacteremia and 193 judged to represent contamination. The most common species detected were Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus haemolyticus. These three species accounted for nearly 98% of the clinically significant isolates and 89% of the contaminants. The isolation of other species almost always represented contamination. However, identification of the three most common species did not help distinguish pathogens from contaminants. Both the Rapid and the Dried Overnight Gram-Positive panels identified S. epidermidis strains accurately, but the panels performed less well for the other species. Analysis revealed that S. hominis was frequently misidentified due to the presence of a previously unknown subspecies. Based on the initial results, revised investigational Dried Overnight Gram-Positive Identification panels (CPID-2) were prepared and tested. The CPID-2 panels identified 85 to 95% of S. epidermidis strains, 76 to 86% of S. hominis strains, and 88 to 92% of S. haemolyticus strains with high probability (>85%) and, overall, represented a significant improvement over the other panels for identification of these staphylococcal species.

Full Text

Duke Authors

Cited Authors

  • Weinstein, MP; Mirrett, S; Van Pelt, L; McKinnon, M; Zimmer, BL; Kloos, W; Reller, LB

Published Date

  • July 1998

Published In

Volume / Issue

  • 36 / 7

Start / End Page

  • 2089 - 2092

PubMed ID

  • 9650970

Pubmed Central ID

  • PMC104986

International Standard Serial Number (ISSN)

  • 0095-1137

Digital Object Identifier (DOI)

  • 10.1128/JCM.36.7.2089-2092.1998


  • eng

Conference Location

  • United States