Pyrrolomycins as potential anti-staphylococcal biofilms agents

With the goal of discovering new anti-infective agents active against microbial biofilms, we focused on some natural pyrrolomycins, a family of halogenated pyrrole antibiotics. In this study we investigated the anti-staphylococcal biofilm activity of pyrrolomycins C, D, F1, F2a, F2b, F3 and of the synthesized related compounds I, II, III. The susceptibility of six staphylococcal biofilms was determined by methyltiazotetrazolium (MTT) staining. Most of the compounds were active at concentrations of 1.5 μg/mL with significant inhibition percentages. A few of the compounds were active at the lowest screening concentration of 0.045μg/mL. We also report the population log reduction of activity against the two best biofilm forming S. aureus strains as determined by viable plate counts. In order to adequately assess the utility of these compounds, their toxicity against human cells was evaluated. In conclusion, pyrrolomycins and synthetic derivatives are promising compounds for developing novel effective chemical countermeasures against staphylococcal biofilms