In Vitro Activity of Silver-Bound Titanium Dioxide (Tiab) Against Multidrug-Resistant Bacteria from Dermatological Infections.

Objectives: To evaluate the in vitro antimicrobial activity of TiAB, a compound based on silver-bound titanium dioxide, against clinical isolates from dermatological infections.

Methods: We tested 155 strains clinically isolated from ulcers and skin infections, including MRSA, ESBL-producing Enterobacterales, and P. aeruginosa. MIC and MBC values were determined using broth microdilution according to CLSI guidelines. Time-kill assays were performed at 0.5×, 1×, and 2× MIC. Median values were used to describe susceptibility profiles.

Results: TiAB exhibited strong bactericidal activity against Gram-negative bacteria, including ESBL-positive E. coli and K. pneumoniae, with complete killing at 2× MIC (4-8%) within 4-8 h. Gram-positive pathogens exhibited higher MICs (≥8%) and limited response within 24 h; however, extending exposure to 48 h resulted in enhanced activity.

Conclusions: TiAB exhibited in vitro bactericidal activity with median MIC values ranging from 1% to 2% (w/v) against Gram-negative clinical isolates such as E. coli and P. aeruginosa, and 2% to 4% against Gram-positive strains including MRSA. Time-kill assays confirmed ≥3 log₁₀ CFU/mL reductions for Gram-negative bacteria at 2× MIC within 24 h. These results suggest TiAB's potential as a topical antimicrobial agent, though further in vivo studies are needed to validate its safety and efficacy.