1887

Abstract

Coagulase-negative staphylococci (CNS) are frequently isolated from blood cultures, where they may be only a contaminant or the cause of bacteraemia. Determining whether an isolate of CNS represents a true CNS bacteraemia is difficult, and there is no single criterion with sufficient specificity. The aim of this study was to assess those clinical, microbiological, pathogenic and genotypic features that characterize true CNS bacteraemia. Twenty patients having two or more blood cultures positive for CNS and 20 patients with only one positive blood culture were studied. Significant bacteraemia was defined according to clinical and laboratory criteria. Incubation time for blood cultures to become positive, macroscopic appearance of colonies, species determination, biotype, susceptibility to antimicrobials, PFGE pattern and adherence capacity were all studied. Clinical bacteraemia was present in 16/20 patients with two or more positive blood cultures and in 2/20 patients with only one positive blood culture. A significant difference was seen in the median time to positivity between the 18 clinical bacteraemias and 22 contaminations (23.6 versus 29.2 h; = 0.04, Wilcoxon). There was also a significant difference between the two groups in the median absorbance of the slime test (1.36 versus 0.58; = 0.005). All significant bacteraemias with two or more positive blood cultures had the same species identified, the same antimicrobial susceptibility pattern and the same PFGE pattern. In two patients with true bacteraemia with only one positive blood culture, the incubation time for the culture to turn positive was <24 h and the slime production absorbance was >2.5. The most useful parameters for the diagnosis of true CNS bacteraemia for patients with two positive blood cultures were incubation time until positive, species identification, antimicrobial susceptibility pattern, slime production and PFGE pattern. For patients with only one blood culture positive for CNS, the useful parameters for prediction of true bacteraemia were incubation time until positive and slime production, both of which are simple, low-cost tests.

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2004-01-01
2024-04-23
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References

  1. Ammendolia M. G., Di Rosa R., Montanaro L., Arciola C. R., Baldassarri L. 1999; Slime production and expression of the slime-associated antigen by staphylococcal clinical isolates. J Clin Microbiol 37:3235–3238
    [Google Scholar]
  2. Arciola C. R., Baldassarri L., Montanaro L. 2001; Presence of icaA and icaD genes and slime production in a collection of staphylococcal strains from catheter-associated infections. J Clin Microbiol 39:2151–2156 [CrossRef]
    [Google Scholar]
  3. Baldassarri L., Simpson W. A., Donelli G., Christensen G. D. 1993; Variable fixation of staphylococcal slime by different histochemical fixatives. Eur J Clin Microbiol Infect Dis 12:866–868 [CrossRef]
    [Google Scholar]
  4. Bates D. W., Cook E. F., Goldman L., Lee T. H. 1990; Predicting bacteremia in hospitalized patients.A prospectively validated model. Ann Intern Med 113:495–500 [CrossRef]
    [Google Scholar]
  5. Bates D. W., Goldman L., Lee T. H. 1991; Contaminant blood cultures and resource utilization.The true consequences of false-positive results. JAMA 265:365–369 [CrossRef]
    [Google Scholar]
  6. Bates D. W., Sands K., Miller E. & 12 other authors; 1997; Predicting bacteremia in patients with sepsis syndrome.Academic Medical Center Consortium Sepsis Project Working Group. J Infect Dis 176:1538–1551 [CrossRef]
    [Google Scholar]
  7. Christensen G. D., Simpson W. A., Bisno A. L., Beachey E. H. 1982; Adherence of slime-producing strains of Staphylococcus epidermidis to smooth surfaces. Infect Immun 37:318–326
    [Google Scholar]
  8. Davenport D. S., Massanari R. M., Pfaller M. A., Bale M. J., Streed S. A., Hierholzer W. J. Jr 1986; Usefulness of a test for slime production as a marker for clinical significant infections with coagulase-negative staphylococci. J Infect Dis 153:332–339 [CrossRef]
    [Google Scholar]
  9. Freeman D. J., Falkiner F. R., Keane C. T. 1989; New method for detecting slime production by coagulase negative staphylococci. J Clin Pathol 42:872–874 [CrossRef]
    [Google Scholar]
  10. García P., Julio C., Calvo M., Sánchez T., Labarca J. 1999; Valor predictivo positivo de staphylococcus coagulasa negativa en hemocultivos . XVI Congreso Chileno de Infectología Chile, abstract: no:78 (in Spanish
    [Google Scholar]
  11. Gemmell C. G. 1986; Coagulase-negative staphylococci. J Med Microbiol 22:285–295
    [Google Scholar]
  12. Herwaldt L. A., Geiss M., Kao C., Pfaller M. A. 1996; The positive predictive value of isolating coagulase-negative staphylococci from blood cultures. Clin Infect Dis 22:14–20 [CrossRef]
    [Google Scholar]
  13. Huebner J., Goldmann D. A. 1999; Coagulase-negative staphylococci: role as pathogens. Annu Rev Med 50:223–236 [CrossRef]
    [Google Scholar]
  14. Hussain M., Collins C., Hastings J. G., White P. J. 1992; Radiochemical assay to measure the biofilm produced by coagulase-negative staphylococci on solid surfaces and its use to quantitate the effects of various antibacterial compounds on the formation of the biofilm. J Med Microbiol 37:62–69 [CrossRef]
    [Google Scholar]
  15. Ishak M. A., Groschel D. H., Mandell G. L., Wenzel R. P. 1985; Association of slime with pathogenicity of coagulase-negative staphylococci causing nosocomial septicemia. J Clin Microbiol 22:1025–1029
    [Google Scholar]
  16. Khatib R., Riederer K. M., Clark J. A., Khatib S., Briski L. E., Wilson F. M. 1995; Coagulase-negative staphylococci in multiple blood cultures: strain relatedness and determinants of same-strain bacteremia. J Clin Microbiol 33:816–820
    [Google Scholar]
  17. Kim S. D., McDonald L. C., Jarvis W. R., McAllister S. K., Jerris R., Carson L. A., Miller J. M. 2000; Determining the significance of coagulase-negative staphylococci isolated from blood cultures at a community hospital: a role for species and strain identification. Infect Control Hosp Epidemiol 21:213–217 [CrossRef]
    [Google Scholar]
  18. Kotilainen P. 1990; Association of coagulase-negative staphylococcal slime production and adherence with the development and outcome of adult septicemias. J Clin Microbiol 28:2779–2785
    [Google Scholar]
  19. Leonard R. B., Carroll K. C. 1997; Rapid lysis of gram-positive cocci for pulsed-field gel electrophoresis using achromopeptidase. Diagn Mol Pathol 6:288–291 [CrossRef]
    [Google Scholar]
  20. MacGregor R. R., Beaty H. N. 1972; Evaluation of positive blood cultures.Guidelines for early differentiation of contaminated from valid positive cultures. Arch Intern Med 130:84–87 [CrossRef]
    [Google Scholar]
  21. Martin M. A., Pfaller M. A., Wenzel R. P. 1989; Coagulase-negative staphylococcal bacteremia.Mortality and hospital stay. Ann Intern Med 110:9–16 [CrossRef]
    [Google Scholar]
  22. Mirret S., Weinstein M. P., Reimer L. G., Wilson M. L., Reller L. B. 1993; Interpretation of coagulase-negative staphylococci in blood culture: does the number of positive bottles help?. In Program and Abstracts of the 93rd General Meeting of the American Society for Microbiology Atlanta, GA, USA:p– 458 abstract C69
    [Google Scholar]
  23. O'Gara J. P., Humphreys H. 2001; Staphylococcus epidermidis biofilms: importance and implications. J Med Microbiol 50:582–587
    [Google Scholar]
  24. Peacock S. J., Bowler I. C., Crook D. W. 1995; Positive predictive value of blood cultures growing coagulase-negative staphylococci. Lancet 346:191–192 [CrossRef]
    [Google Scholar]
  25. Sloos J. H., Dijkshoorn L., Vogel L., van Boven C. P. 2000; Performance of phenotypic and genotypic methods to determine the clinical relevance of serial blood isolates of Staphylococcus epidermidis in patients with septicemia. J Clin Microbiol 38:2488–2493
    [Google Scholar]
  26. Weinstein M. P., Towns M. L., Quartey S. M., Mirrett S., Reimer L. G., Parmigiani G., Reller L. B. 1997; The clinical significance of positive blood cultures in the 1990s: a prospective comprehensive evaluation of the microbiology, epidemiology, and outcome of bacteremia and fungemia in adults. Clin Infect Dis 24:584–602 [CrossRef]
    [Google Scholar]
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