The gram-negative coccobacillus Acinetobacter baumannii has frequently been associated with infections occurring after the hospitalization of patients in intensive care units. Its dissemination in hospitals has been favored by its ability to form biofilms, a matrix composed of carbohydrates, proteins, nucleic acids, and other macromolecules, on surfaces and medical devices. Studies have shown that mechanisms related to reduced microbial susceptibility tend to promote cross-resistance among antibiotics, biocides, and disinfectants, contributing to longer hospital stays and increased resistance to available antimicrobials. In addition, few biocides are available on the market, and some already have intrinsic resistance documented and exacerbated by incorrect use and concentration. Even so, progress in the development of strategies for new compounds acting on devices and surfaces remains limited.

The study was conducted with clinical isolates from a hospital in southern Brazil. The ability to form microbial biofilms was determined as proposed by Halicki et al. (2019). Subsequently, in polystyrene plates, 10⁶ CFU/mL of each isolate was exposed to three concentrations of EDTA (12, 0.6, and 0.3 mM). After incubation for 24 hours at 37°C, the inhibitory capacity of biofilm formation was evaluated using 0.4% crystal violet as an indicator.

Half of the isolates (5/10) were classified as moderate biofilm formers. Regarding the biofilm inhibition potential of EDTA, which has a high capacity for metal ion chelation, it was observed that the mean inhibition was 90.8% at a concentration of 12 mM, 82.2% at 0.6 mM, and 22% at 0.3 mM.

The ability of the chelating agent EDTA to interact with cations that maintain the structural stability of the bacterial outer membrane may make it more susceptible to the entry of antimicrobial agents and to cell lysis, thereby inhibiting the initial stages of biofilm formation. In this context, EDTA demonstrates potential to inhibit this important virulence mechanism of A. baumannii, highlighting the relevance of further studies exploring its mechanism of action and potential as a biocidal agent.