Screening and isolation of microbes from a Mud Community of Ischia Island Thermal Springs: preliminary analysis of a bioactive compound

Introduction: Balneotherapy centers of Ischia island (Italy) offer treatments for different dermatological diseases (psoriasis, acne, atopic dermatitis) and upper respiratory tract infections. In this study, we integrated morphological and molecular approaches to give bacterial diversity of microbial mat samples collected from the thermae of Ischia. Methods: Samples were collected during 2019 at four sites. Some bacterial strains ATCC for antibacterial and antibiofilm Activity were tested. After morphological characterization, screening for antagonistic isolates was made. The colonies isolated from thermal mud samples were submitted to molecular characterization. Susceptibility testing by dilution spotting was carried out and antibacterial efficacies of most active isolate were evaluated with a Minimal inhibition concentration assay. Biofilm formation, inhibition, eradication were examined. Statistical analyses were carried out utilizing Microsoft® Excel 2016/XLSTAT©-Pro. Results: We isolated a natural compound with antimicrobial and antibiofilm activities. Conclusions: The results obtained in this study are discussed in the context of how hydrothermal systems are important environmental source of uncharted antimicrobial and antibiofilm compounds. This is, to our knowledge, the first view of a spring water microbiome analysis of Ischia.