The objective of NEOPOPI is to conduct a population pharmacokinetic study of amoxicillin in neonates, in order to evaluate and optimize neonatal dose regimen.

There will be no change to the medication treatment received by participants. An opportunistic pharmacokinetic sampling approach will be followed: samples will be scavenged from blood or cerebrospinal fluid drawn for routine biochemical tests. In this way, no additional invasive tests will be needed.

• Administration of the antibiotic according to the usual procedures for prescribing services: in particular, neither the indications nor the doses nor the methods of administration are fixed by the protocol
• Opportunistic sampling strategy: no biological samples are specifically collected for the purposes of the study (measurements of concentrations on "bottoms" or "left-over" samples); the performance of this non-invasive sampling strategy has been previously demonstrated in the neonatal population.
• Micro-analytical method (assay of concentrations on micro-volumes, of the order of 50μL)
• Population pharmacokinetic analysis

Inclusion Criteria:

• Neonates receiving amoxicillin and blood/CSF tests during amoxicillin treatment, as part of their routine clinical care
• No parental opposition to the study participation

Exclusion Criteria:

• None

Neonates (including both preterm and full-term neonates) receiving amoxicillin as part of their routine clinical care (for suspected or proven neonatal sepsis).