Clofoctol (o-CLO): isolation from cave environment, radioiodination and its antibiofilm effect

Abstract Antibiotics are commonly used worldwide to treat microbial infections. However, the prolonged overuse of antibiotics has given rise to antibiotic resistance. Innovative approaches are needed for the diagnosis and treatment of bacterial infections, especially those caused by biofilm-forming bacteria. One approach is to use organic antibiotics produced by cave bacteria as an alternative to synthetic antibiotics. We explored the antibiotic production potential of bacteria isolated from the third deepest cave in Turkey. Following the purification of the antibiotic clofoctol (CLO) from cave bacteria, minimal inhibitory concentrations of organic, radioactively, and inertly labelled CLO against Staphylococcus aureus were compared with minimal inhibitory concentrations of synthetic, radioactively, and inertly labelled CLO. The antibiofilm effects of antibiotics, as well as their labelled derivatives, were also determined. When the effect of radiolabeled antibiotics on the number of bacteria in the biofilm was examined, it was found that they exhibited more pronounced effects with increasing antibiotic concentrations. After 24 h of incubation, the bacterial numbers in the biofilm for radiolabeled antibiotic concentrations of 4 µg/mL were determined to be 3.4 and 2.9 Log10 CFU/mL, respectively. When all experimental results were evaluated, it was observed that 131 I-o-CLO is promising as a new strategic anti-biofilm agent.