Target attainment of cefotaxime in critically ill children with meningococcal septic shock as a model for cefotaxime dosing in severe pediatric sepsis

Reduced target attainment of β-lactam antibiotics is reported in critically ill patients. However, as target attainment of cefotaxime in severely ill pediatric sepsis patients may differ from adults due to age-related variation in pharmacokinetics, we aimed to assess target attainment of cefotaxime in this pilot study using meningococcal septic shock patients as a model for severe sepsis. Secondary analysis of prospectively collected data from a randomized controlled trial. Children with meningococcal septic shock (1 month to 18 years) included in this study received cefotaxime 100–150 mg/kg/day as antibiotic treatment. Left-over plasma samples were analyzed using LC-MS/MS to determine cefotaxime concentrations. MIC values from EUCAST were used to determine target attainment of cefotaxime for Neisseria meningitidis (0.125 mg/l), but also for Streptococcus pneumoniae (0.5 mg/l), Enterobacteriaceae (1 mg/l), and Staphylococcus aureus (4 mg/l). Target attainment was adequate when all samples exceeded MIC or fourfold MIC values. One thirty-six plasma samples of 37 severe septic shock patients were analyzed for cefotaxime concentrations. Median age was 2 years with a median PRISM-score of 24 and mortality of 24.8%. The median unbound cefotaxime concentration was 4.8 mg/l (range 0–48.7). Target attainment ranged from 94.6% for the MIC of N. meningitidis to 16.2% for fourfold the MIC S. aureus. Creatinine levels were significantly correlated with cefotaxime levels. Target attainment of cefotaxime with current dosing guidelines seems to be adequate for N. meningitidis but seems to fail for more frequently encountered pathogens in severely ill children.