hdr isap

News December 2013

Tissue concentrations again (Eng`s principle of medical procedures: „The easier it is to do, the harder it is to change.“)
Stein et al recently published a paper in the Journal of Antimicrobial Chemotherapy reporting the tissue penetration of trimethoprim/sulfamethoxazole and linezolid in patients with diabetic foot infection to support their use in the treatment of diabetic foot infections (JAC 2013; 68: 2852–2858). This study used tissue biopsy homogenates to determine the concentrations at the site of infection, a method that measures a mixture of total (bound+free) concentrations in intra-, extracellular and blood compartments where antibiotics and bacteria are not distributed evenly. It is difficult to discourage methods that are easy and cheap though they bring potenially misleading results.
ISAP and the ESCMID PK/PD study group submitted a response to JAC with the intention to raise awareness regarding methodological pitfalls of tissue concentration measurements.