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Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures.

Publication ,  Journal Article
Mirrett, S; Weinstein, MP; Reimer, LG; Wilson, ML; Reller, LB
Published in: J Clin Microbiol
September 2001

Coagulase-negative staphylococci (CNS) are the most commonly isolated contaminants from blood cultures, yet they frequently cause true infections. Determining the clinical significance of CNS is difficult, and clinicians often consider the number of positive bottles within a set of blood culture bottles in their assessment. Therefore, in three separate studies, we counted the number of positive bottles within blood culture sets comprising two, three, or four bottles in order to predict whether or not CNS were clinically significant isolates (CSI) in adult patients with suspected sepsis. Each culture was evaluated by independent, published clinical criteria to determine its clinical importance. Of 486 positive sets that included two adequately filled bottles, 127 (26%) CNS were CSI, 329 (67%) were contaminants, and 30 (6%) were indeterminate as a cause of sepsis. Among CSI, 39 and 61% were isolated from one and two bottles, respectively. The positive predictive value for sepsis was 18% when one bottle was positive and 37% when both bottles were positive. Of 235 positive sets that included three adequately filled bottles, 81 (34%) were CSI, 109 (46%) were contaminants, and 45 (19%) were indeterminate as a cause of sepsis. Of CSI, 43, 38, and 19% were found in one, two, and three bottles, respectively. The positive predictive value for sepsis was 28, 52, and 30% when one, two and three bottles were positive. Of 303 positive blood culture sets that included four adequately filled bottles, 64 (21%) were considered CSI, 197 (65%) were contaminants, and 42 (14%) were indeterminate as a cause of sepsis. Of CSI, 27, 28, 19, and 27% were found in one, two, three, and four bottles, respectively. The positive predictive value for sepsis was 11, 30, 34, and 37% when one, two, three, and four bottles were positive. We conclude that the number of culture bottles positive in a given culture set cannot reliably predict the clinical significance of the CNS isolated and, therefore, should not be used as a criterion for determining whether or not an isolate represents true infection or contamination.

Duke Scholars

Published In

J Clin Microbiol

DOI

ISSN

0095-1137

Publication Date

September 2001

Volume

39

Issue

9

Start / End Page

3279 / 3281

Location

United States

Related Subject Headings

  • Staphylococcus
  • Staphylococcal Infections
  • Sepsis
  • Microbiology
  • Humans
  • Equipment Contamination
  • Culture Media
  • Coagulase
  • Blood
  • Bacteriological Techniques
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Mirrett, S., Weinstein, M. P., Reimer, L. G., Wilson, M. L., & Reller, L. B. (2001). Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures. J Clin Microbiol, 39(9), 3279–3281. https://doi.org/10.1128/JCM.39.9.3279-3281.2001
Mirrett, S., M. P. Weinstein, L. G. Reimer, M. L. Wilson, and L. B. Reller. “Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures.J Clin Microbiol 39, no. 9 (September 2001): 3279–81. https://doi.org/10.1128/JCM.39.9.3279-3281.2001.
Mirrett S, Weinstein MP, Reimer LG, Wilson ML, Reller LB. Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures. J Clin Microbiol. 2001 Sep;39(9):3279–81.
Mirrett, S., et al. “Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures.J Clin Microbiol, vol. 39, no. 9, Sept. 2001, pp. 3279–81. Pubmed, doi:10.1128/JCM.39.9.3279-3281.2001.
Mirrett S, Weinstein MP, Reimer LG, Wilson ML, Reller LB. Relevance of the number of positive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures. J Clin Microbiol. 2001 Sep;39(9):3279–3281.

Published In

J Clin Microbiol

DOI

ISSN

0095-1137

Publication Date

September 2001

Volume

39

Issue

9

Start / End Page

3279 / 3281

Location

United States

Related Subject Headings

  • Staphylococcus
  • Staphylococcal Infections
  • Sepsis
  • Microbiology
  • Humans
  • Equipment Contamination
  • Culture Media
  • Coagulase
  • Blood
  • Bacteriological Techniques