Microorganisms (IMAGE) PLOS Caption Bacteria detected on the painting: Samples were collected from the recto (a, b, c) and the verso (d, e, f) of the painting. a) colonies of Staphylococcus spp. on a Mego agar plate; b) the same Staphylococcus spp. viewed by OM after Gram staining (original magnification 100X) and c) by SEM. d) colonies of Bacillus spp. on a TSA agar plate; e) the same Bacillus spp. viewed by OM after Gram staining (original magnification 100X) and f) SEM. Credit Caselli et al., 2018 Usage Restrictions CC-BY: Redistribution permitted with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.