Vancomycin drug monitoring in infants with CoNS sepsis-target attainment, microbiological response and nephrotoxicity.

Objectives: To characterize residual vancomycin concentrations (Cmin) and assess the relationships between Cmin, the risk of nephrotoxicity and persistent CoNS sepsis.

Methods: In this 5-year retrospective study among infants treated with vancomycin, the primary outcome was the proportion of those with a steady state Cmin between 10 and 20 mg/L. The secondary outcomes were nephrotoxicity and persistent CoNS sepsis.

Results: Of 120 infants included, the median first steady state Cmin was 12.4 mg/L and 77 (64%) had a Cmin between 10 and 20 mg/L. Six percent developed nephrotoxicity. This risk was not associated with Cmin. Of the 30 infants with CoNS sepsis, 17 (57%) had persistent bacteremia, and this risk did not correlate significantly with Cmin, CoNS minimal inhibitory concentration (MIC) for vancomycin, or Cmin/MIC.

Conclusions: The majority of infants achieved targeted levels of vancomycin, but persistent bacteremia was common. We did not identify a Cmin threshold associated with nephrotoxicity, nor with microbiological clearance.