Described is a an object comprising a polymer coating, the coating comprising one or more polymers,wherein said polymers comprise a first cleavage site,and a first agent releasable from said coating upon cleavage of said first cleavage site. The first cleavage site is cleaved by a first compound specifically provided by a microbe belonging to a first group consisting of a limited number of microbial strains, species or genera, and not cleaved by any compound provided by any microbe not belonging to said first group, wherein cleavage of the said first cleavage site results in release of the said first agent from the coating, the release of said first agent being indicative for the presence of a microbe belonging to the said first group. Further, methods of detecting a microbial infection and of visualizing the presence of microbes are presented.
