Monitoring the colonization of monuments by bacteria: cultivation versus molecular methods

Abstract

Building materials commonly used in wall paintings and monuments (mortar, limestone and sandstone) were inoculated with an artificial consortium composed of 14 microorganisms and incubated for 6 months at 28°C. The colonization of the different materials by the consortium was investigated. Culture-independent techniques revealed the presence of a diversity of bacteria, whereas culture-dependent techniques yielded mainly spore-forming bacteria. The data suggest that plating leads to an overestimation of the number of spore-forming bacteria with respect to quiescent vegetative forms; the latter are less easily cultured, but are readily detected by culture-independent techniques.