Background: Kocuria kristinae (earlier known as Rothia kristinae) is a relatively new opportunistic pathogen responsible for ear infections. The ability of this organism to form biofilms increases its resistance to therapy and promotes the development of antimicrobial resistance, necessitating new treatment methods. Objective: To assess the effect of 3-caffeoylquinic acid on K. kristinae isolated from patients with ear infections. Methods: Isolation of five clinical strains was done by conventional microbiological procedures. The ability of K. kristinae to form biofilms was determined by the crystal violet method (absorbance at OD₅₇₀) before and after 3-caffeoylquinic acid exposure; statistical data analysis was done using a paired t-test (p < 0.05). Results: All strains showed the presence of strong biofilm production ability before treatment (OD 0.54–0.80). After treatment, it was significantly reduced (0.642 ± 0.108 vs 0.124 ± 0.025), by 80.7%. All the isolates changed from being strong biofilm formers to weak ones (p < 0.05). Conclusion: 3-caffeoylquinic acid exhibited strong antibiofilm activity against K. kristinae isolates, suggesting it could be used as an alternative treatment for ear infections. In vivo studies need to be further carried out.
