Antibacterial Activity of Geraniol in Prevalent and Resistant Bacteria of the Oral Microbiota of Patients

Dysbiotic diseases of the oral microbiota, such as dental caries, endodontic infections, and periodontitis, represent a clinical challenge due to bacterial resistance and biofilm formation. In this context, plant-derived secondary metabolites such as Geraniol have emerged as promising alternatives owing to their low toxicity and multiple mechanisms of action. This study aimed to evaluate the antibacterial and antibiofilm activity of Geraniol against resistant and prevalent bacterial species from the oral microbiota of patients treated at the Dental Clinic of the Federal University of Pernambuco (UFPE). Samples were collected from patients with oral alterations, and microorganisms were identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Antimicrobial susceptibility was determined using the VITEK® automated system. Multidrug-resistant (MDR) isolates and reference strains were selected to assess the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and antibiofilm activity of Geraniol. A total of 74 isolates were identified, including Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, and Pseudomonas stutzeri, with 60% classified as MDR. Geraniol exhibited significant inhibitory activity against Streptococcus mutans (ATCC 700610) and Enterococcus faecalis (ATCC 29212), with an MIC of 0.032 mg/mL. Furthermore, Geraniol inhibited biofilm formation in six isolates of S. mutans and E. faecalis. These findings highlight the potential of Geraniol as a therapeutic alternative for resistant oral infections, particularly in dysbiosis-associated biofilms. Future studies should explore its clinical applications and potential combinations with other agents to overcome bacterial resistance and improve outcomes in the treatment of oral diseases.