Pharmacodynamics of antibiotics in fibrin clots.

Fibrin is an integral component of intravascular thrombus, surgical wounds, haematomas, vegetations and foreign bodies which predispose to infection. The tropism that many pathogens have for fibrin may favour bacterial growth and lead to infection. To improve our understanding of the pharmacodynamic interaction between antibiotics and pathogens infecting fibrin clots, this review will: define the role of fibrin as a protective environment for microorganisms; give an historical perspective of in-vitro and in-vivo fibrin clots; describe the pharmacodynamic model of infected fibrin clots; review pharmacodynamic determinants of outcome; and discuss intramicrobial pharmacokinetics. Fibrin clots are hard to penetrate following antibiotic administration and there is a major gradient of concentration from the surface to the core of the clots which has great influence on bacterial growth and lysis. Resistance can develop and morphological and structural changes in bacteria may vary within the different regions of the clot.