The study will be conducted to investigate the pharmacokinetics of ampicillin / sulbactam and amoxicillin/clavulanic acid during intermittent haemodialysis.

Inclusion Criteria:

• Age >18 years
• Suspected or proven bacterial infection requiring parenteral antibiotic therapy.
• Renal replacement therapy (HD)

Exclusion Criteria:

• Known hypersensitivity to ampicillin / sulbactam, amoxicillin / clavulanic acid or other beta-lactames, or severe hypersensitivity (anaphylactic reaction) to beta-lactam antibacterial agents.
• An expected survival of less than two days.
• Known pregnancy
• Co-administration of one of the following drugs: probenecid which cannot be discontinued for the duration of the study
• Ampicillin / sulbactam respectively amoxicillin / clavulanic acid as monotherapy for resistant species or fungal infections.
• Other reasons opposing the study participation on the discretion of the investigators.