Comparison between MRI, microbiology and histology in evaluation of antibiotics in a murine model of thigh infection.

Although in vivo magnetic resonance imaging (MRI) is rapidly becoming a recognised tool in experimental pharmacological research, at the best of our knowledge, scarce application in the field of antibacterial drug research has been reported so far. In this last field, animal models of bacterial infections are used to test the efficacy of novel compounds. In this paper we have explored the potential usefulness of MRI in monitoring the chronological evolution of experimental bacterial infections and the effect of different therapeutic treatments. A murine model of thigh infection induced by Staphylococcus aureus has been used and the efficacy of vancomycin and imipenem/cilastatin has been tested. Three groups of infected animals were studied by microbiology, histology and MRI methods. The results obtained show that in vivo MRI data are highly consistent with microbiological and histological data, allowing, similarly to these commonly used techniques, the efficacy of different antibacterial treatments to be quantified. Our findings suggest that MRI could be used to assess the efficacy of new chemical entities in antibacterial pharmacological research. The advantages of MRI, as a non invasive technique, in comparison with commonly used microbiological and histological methods are discussed.