control of opportunistic oral cavity infections using postbiotics secreted by aerobic oral flora, with minimal impact on host cells

Introduction: postbiotics derived from the natural oral microbiome offer a potential solution for chemotherapy-induced oral dysbiosis by restoring microbial balance. these compounds hold promise for managing oral infections, particularly in vulnerable populations, by restoring microbial balance, directly inhibiting pathogen growth, and promoting a healthy mucosal immune response. this study evaluates the antimicrobial activity of postbiotics derived from aerobic oral bacteria against staphylococcus aureus and assesses their cytotoxicity in human cells, contributing to the development of new therapeutic strategies for oral infections. methods: specific strains of aerobic oral bacteria were isolated and cultured in nutrient broth at 37°c in a 5% co2 atmosphere. after 24 h of incubation, the supernatant containing postbiotics was collected and centrifuged, followed by filtration to isolate the postbiotics. the antibacterial activity of these postbiotics was assessed against s. aureus isolated from oral wounds using the agar well diffusion method on mueller-hinton agar plates. in parallel, the cytotoxic effects on normal human dermal fibroblasts (nhdf) were evaluated through mtt viability assays to measure metabolic activity, and sybr green staining to quantify dna content, and assess cell membrane integrity. statistical analysis was performed using one-way anova followed by tukey’s post-hoc test, with significance set at p < 0.05. results: postbiotics exhibited significant antimicrobial activity against s. aureus, as evidenced by a mean zone of inhibition of 17.0 mm (±1.4 mm), while no inhibition was observed in saline controls. furthermore, postbiotics treatment resulted in nhdf cell viability of 94% (±1.6%) compared to the untreated controls 75.2% (±0.7%); p < 0.0001, demonstrating their biocompatibility. conclusion: this study demonstrates the promising therapeutic potential of postbiotics for combating opportunistic oral infections, exhibiting negligible cytotoxicity towards host cells. future research will explore isolating and identifying the active components of these postbiotics and evaluating their efficacy in vivo models and human oral cell lines.