Coagulase-negative Staphylococcus bacteraemia accounts for one third of Staphylococcus bacteraemia in a French university hospital

Abstract

Background: We sought to determine the epidemiological patterns of Staphylococcus bacteraemia, with a focus on the proportion of coagulase-negative Staphylococcus (CoNS) as compared to Staphylococcus aureus bacteraemia, and the prognosis. Methods: All patients with significant Staphylococcus bacteraemia at the university hospital in Reims in 2008 were included in the study. Data were retrieved retrospectively from the patient records using a standardized case investigation form. Quantitative variables were compared using the Mann–Whitney U-test and qualitative variables were compared using Fisher's exact test or Pearson's Chi-square test, as appropriate. Bivariate logistic regression was performed on both S. aureus and CoNS bacteraemia. All variables with a p-value of < 0.15 were entered into a multiple logistic regression model. Results: CoNS represented 31.6% of all strains isolated. The methicillin resistance rate was higher in CoNS (66.1%) than in S. aureus (19.1%) (p < 0.0001). CoNS were more frequently associated with intravascular catheters and neoplastic disease, whereas S. aureus was associated with chronic renal failure (p < 0.0001) and diabetes mellitus (p = 0.004). Mortality was 30.7% for S. aureus and 19.6% for CoNS bacteraemia (p = 0.12). Methicillin resistance was not associated with mortality (p = 0.99). Factors independently associated with mortality in CoNS and S. aureus bacteraemia were age and acute renal failure. The presence of severe sepsis/septic shock was only associated with mortality in S. aureus bacteraemia. Conclusions: CoNS represent one third of Staphylococcus bacteraemia. The mortality difference between CoNS and S. aureus bacteraemia was not statistically significant. Acute renal failure is associated with mortality in both S. aureus and CoNS bacteraemia.

Keywords::

• Bacteraemia
• coagulase-negative Staphylococcus
• epidemiology
• acute renal failure

Acknowledgements

We thank the following Professors and Doctors, and their secretariat, for allowing us access to the medical records: Prof. S. Backchine, Prof. B. Baehrel, Dr A. Bazin, Prof. P. Bernard, Prof. F. Blanchard, Prof. A. Chays, Prof. C. Clement, Prof. E. Dehoux, Prof. J. F. Delattre, Prof. B. Delemer, Prof. A. Delmer, Prof. J. P. Eschard, Prof. F. Lebargy, Prof. A. Leon, Prof. D. Metz, Prof. J. L. Pennaforte, Prof. P. Rieu, Prof. P. Rousseaux, Prof. F. Staerman, Prof. G. Thieffin.

Declaration of interest: The authors declare that they have no conflict of interest.