Background: Routine surveillance by our antimicrobial stewardship program identified an increased linezolid usage. In parallel, our 2014 institutional antibiogram reflected a reduction in linezolid-susceptible Enterococcus isolates. These observations prompted a retrospective review of linezolid use in our children's hospital from 2007-2014 to investigate if the linezolid use was associated with the reduction in the rate of linezolid susceptible Enterococcus isolates.
Methods: The Pediatric Health Information Systems database was used to determine the number of hospitalized patients receiving linezolid between 2007 and 2014 inclusive. Primary discharge ICD-9 code associated with each use of linezolid was identified and these were grouped by clinical syndrome or organ system. Hospital antibiograms for the same period were reviewed to determine changes in susceptibility patterns of Enterococcus isolates.
Results: The proportion of E. faecalis and E. faecium isolates susceptible to linezolid fell from 95% and 100%, respectively, in 2007 to 45% and 46% in in 2014. During the same timeframe linezolid use was found to have increased five-fold from 15 cases/year in 2007 to 80 cases/year in 2014 (Figure 1). The most common ICD-9 discharge diagnosis codes of the hospitalized pediatric patients receiving linezolid varied by the year. While linezolid use for cellulitis and pneumonia remained relatively constant over the years reviewed, an yearly increase in use for patients with cystic fibrosis and heart disease was observed.
Conclusion: Linezolid susceptibility among Enterococcal isolates at our institution between 2007 and 2014 has declined in association with a concomitant increase in linezolid use. These events seem to be temporally although a causal association cannot be established. The greatest increase in linezolid use was occurred among patients with discharge diagnoses of cystic fibrosis and heart disease. In response to these observations, linezolid use guidelines and prospective audit with feedback to prescribers have been implemented by our antimicrobial stewardship program.
S. R. Arnold, None
D. Guimera, None
S. Buckingham, None
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