In this prospective observational study, the investigators want to document pharmacokinetic/pharmacodynamic (PK/PD) target attainment of frequently used antimicrobials in an adult non critically ill surgery population (abdominal surgery, traumatology and septic orthopedic surgery). Furthermore, the investigators want to identify risk factors for not attaining predefined PK/PD targets.

The antibiotics of interest are amoxicillin(-clavulanic acid), flucloxacillin, piperacillin-tazobactam, meropenem and clindamycin.

In this research proposal, the primary objective is to describe PK parameters (area under the curve (AUC), clearance (Cl), distribution volume (Vd) and half life (T1/2)) for the antibiotics of interest (amoxicillin(-(clavulanic acid), flucloxacillin, piperacillin-tazobactam, meropenem and clindamycin) for this adult non critically ill surgery population.

Besides, the investigators want to document pharmacokinetic/pharmacodynamic (PK/PD) target attainment of frequently used ABs in this population and to identify risk factors, for example augmented renal clearance (ARC), for not attaining predefined PK/PD targets.

Inclusion Criteria:

Every adult non-critically ill surgery patient admitted at the abdominal, trauma or septic orthopaedic surgery wards from the University Hospitals Leuven treated with multiple doses of one of the antimicrobials of interest (i.e. intravenous (IV) amoxicillin(-clavulanic acid), flucloxacillin, piperacillin-tazobactam, meropenem, oral or IV clindamycin) is eligible for inclusion.

Exclusion Criteria:

• age ≤ 18 years
• treatment restrictions corresponding to a Do Not Reanimate code
• pregnancy
• lactation
• renal replacement therapy
• planned discharge or surgery in the coming antimicrobial dosing interval making sampling impossible

adult non-critically ill surgery patient admitted at the abdominal, trauma or septic orthopaedic surgery wards from the University Hospitals Leuven