Echoes of 1816: microbial footprints in heritage artifacts from Argentina’s museum of independence

Abstract

Historical artifacts preserved in museums are invaluable cultural treasures, yet often vulnerable to biodeterioration caused by microbial colonization. This study presents the first comprehensive investigation of bacteria inhabiting heritage artifacts from Casa Histórica, Argentina’s Museum of Independence. By integrating advanced microscopy with phenotypic and genomic characterization, we analyzed samples collected from wooden objects, textiles, architectural elements, and exterior walls. Scanning electron microscopy revealed diverse and well-structured biofilms, with intricate three-dimensional arrangements embedded in extracellular polymeric substances. A total of 49 bacterial strains were isolated and identified via VITEK MALDI-TOF mass spectrometry, with a predominance of Gram-positive genera such as Bacillus, Micrococcus, and Kocuria. Remarkably, the 19th-century albumen print photograph emerged as the most biodiverse artifact, yielding 21 distinct strains, including Streptomyces, Oceanobacillus, and Caldibacillus thermoamylovorans. The protein-rich and halophilic environment of the albumen layer likely facilitated microbial colonization and persistence. Pseudomonas species were exclusively associated with this photographic substrate, further underscoring its niche specificity. Human-associated taxa like Staphylococcus epidermidis and Staphylococcus equorum were prevalent in high-contact areas, while exterior surfaces displayed distinct microbial signatures, including potential pathogens linked to environmental exposure. These findings reveal a complex and artifact-specific microbial landscape, emphasizing the need for tailored, bio-informed conservation strategies. This work advances the field of heritage microbiology and supports efforts to safeguard culturally significant objects through a deeper understanding of their microbial ecosystems.