The investigators will determine the difference of pharmacokinetics of ciprofloxacin and imipenem between healthy volunteers and intensive care patients suffering from pneumonia in plasma and at the target site - lung - using bronchoalveolar lavage. As additional aspect the feasibility of combining microdosing of C14 ciprofloxacin with microdialysis, saliva sampling and bronchoalveolar lavage is studied by comparing pharmacokinetics of microdose and macrodose.