In Vitro Activity of Silver-Bound Titanium Dioxide (TiAB) Against Multidrug-Resistant Vaginal Pathogens

<b>Background:</b> Gynecological infections, including bacterial vaginosis, vulvovaginal candidiasis, and recurrent urinary tract infections, represent a major clinical burden and are often complicated by biofilm formation and antimicrobial resistance. Novel non-antibiotic strategies are urgently needed. We previously demonstrated the antimicrobial activity of silver-bound titanium dioxide (TiAB) against multidrug-resistant bacteria isolated from dermatological infections. <b>Objectives:</b> We evaluated whether TiAB, at concentrations used in marketed medical devices, exerts antibacterial and antifungal effects against clinically relevant vaginal isolates by determining Minimum Inhibitory Concentration/ Minimum Bactericidal and Fungicidal Concentration (MIC, MBC/MFC), and time-kill kinetics. <b>Methods:</b> A total of 73 clinical isolates were collected from vaginal swabs, including Staphylococcus aureus (MSSA, MRSA), <i>Escherichia coli</i> (ESBL+ and non-ESBL), <i>Klebsiella pneumoniae</i>, <i>Enterococcus</i> spp., <i>Streptococcus agalactiae</i>, and <i>Candida albicans</i>. Minimum inhibitory concentrations (MICs) and minimum bactericidal/fungicidal concentrations (MBCs/MFCs) were determined by broth microdilution, and bactericidal activity was confirmed by time-kill assays. <b>Results:</b> TiAB exhibited potent activity against Gram-negative bacteria, with median MIC values of 1-2% (<i>w</i>/<i>v</i>) for <i>E. coli</i> and <i>K. pneumoniae</i>. Gram-positive isolates, including <i>S. agalactiae</i> and <i>Enterococcus</i> spp., showed higher MIC values (2-4%). Candida albicans displayed fungistatic inhibition at 4%. Time-kill assays confirmed rapid bactericidal effects for Gram-negative isolates within 8 h at 2× MIC, while Gram-positive bacteria required prolonged exposure. <b>Conclusions:</b> These findings extend previous evidence of TiAB's antimicrobial properties to gynecological pathogens, supporting its potential as a topical, non-antibiotic option for managing vaginal infections in an era of rising antimicrobial resistance. Further in vivo validation is warranted.