Inhibitory potential of 1,10-phenanthroline against Acinetobacter baumannii

Acinetobacter baumannii is a Gram-negative bacterium associated with hospital-acquired infections and is frequently resistant to multiple antibiotics, making the search for new therapeutic strategies necessary. As iron plays an essential role in the survival and virulence of this pathogen, this study evaluated the antimicrobial activity of 1,10-phenanthroline and ethylenediaminetetraacetic acid (EDTA) against ten clinical isolates of A. baumannii , the antibiofilm and cytotoxic effects of 1,10-phenanthroline in Vero cells (BCRJ 0245) and the in silico physicochemical and pharmacokinetic profiles of 1,10-phenanthroline, EDTA, and ciprofloxacin. The minimum inhibitory concentration (MIC) of the two chelating agents ranged from 0.85 to 223.3 µg/mL, with 1,10-phenanthroline showing the most notable results (MIC ranging from 0.85 to 13.5 µg/mL). In addition, 1,10-phenanthroline inhibited biofilm formation, with percentages ranging from 24.4% to 88.9% among the evaluated isolates, and showed no cytotoxicity in Vero cells up to the highest concentration tested (1600 µg/mL). The in silico evaluation demonstrated the hydrophilic nature of EDTA and the lipophilicity of 1,10-phenanthroline, indicating greater potential for absorption and interaction with bacterial membranes, in contrast to the balanced profile of ciprofloxacin. Therefore, the results indicate that 1,10-phenanthroline exhibits antimicrobial activity, encouraging further investigations into its application against A. baumannii .