Described is the use of a microorganism or cell containing a DNA sequence encoding a detectable protein or a protein capable of inducing a detectable signal, e.g., a luminescent or fluorescent protein for the preparation of a diagnostic composition for diagnosis and/or visualization of wounded or inflamed tissue or a disease associated therewith. Moreover, therapeutic uses are described, wherein said microorganism or cell additionally contain an expressible DNA sequence encoding a protein suitable for therapy, e.g. an enzyme causing cell death or digestion of debris. <;IMAGE>;