A Novel Approach to Combat Antibiotic Resistance in Nosocomial Infections: Exploring the Synergistic Potential of Berberine and Glycerol Aziza Abugaliyeva, Annette Vincent, and Simon Faulkner Biological Sciences Program, Carnegie Mellon University Qatar Abstract Introduction Figure 1. Calibration curve for Berberine Chloride (BC) in Methanol. 10-50 ug/mL dilutions of BC were prepared using methanol. The absorbance was measured at 429 nm using Agilent 8453 UV-Vis spectrophotometer. Conclusions and Future Work References [1] Wojtyczka, R., Dziedzic, A., Kępa, M., Kubina, R., Kabała-Dzik, A., Mularz, T., & Idzik, D. (2014). Berberine Enhances the Antibacterial Activity of Selected Antibiotics against Coagulase-Negative Staphylococcus Strains in Vitro. Molecules, 19(5), 6583–6596 [2] Nguyen, H. T., Pham, T. N., Le, A. T., Thuy, N. T., Huy, T. Q., & Nguyen, T. T. T. (2022). Antibacterial activity of a berberine nanoformulation. Beilstein journal of nanotechnology, 13, 641–652. [3] AlMulla, M. (2023). Solubility Verification of Berberine Chloride (BC) in Natural Deep Eutectic Solvents (NADES) for the Development of Novel Antimicrobial Agents, CMUQ. [4] Battu, S. K., Repka, M. A., Maddineni, S., Chittiboyina, A. G., Avery, M. A., & Majumdar, S. (2010). Physicochemical characterization of berberine chloride: a perspective in the development of a solution dosage form for oral delivery. AAPS PharmSciTech, 11(3), 1466– 1475. • BC is an isoquinoline alkaloid extracted from plants. It exhibits weak antimicrobial activity against E. coli by itself [1]. • Early studies proposed certain approaches such as synergistic effects with other antimicrobial drugs to increase the effectiveness of BC [2]. • BC has limited solubility in water (1.96 ± 0.11 mg/mL) but it was found to readily dissolve in glycerol which stabilizes bacterial growth and prevents any damage to the cell membrane [3] [4]. Acknowledgments I want to express my immense gratitude to Dr. Simon Faulkner, Dr. Annette Vincent, and Ms. Maria Navarro for their guidance, assistance, and support throughout this research. Methods Gly 5% Gly 10% Gly 15% Gly LB+ LB+ LB+ Water LB Nosocomial infections, acquired during hospital treatment, are a significant challenge in healthcare settings. They are often caused by pathogens like E. coli, which have multiple virulence genes, making traditional treatments less effective due to antibiotic resistance. Berberine chloride (BC), a compound derived from the plant genus Berberis comprised of ~450-500 species, has shown antimicrobial activity against E. coli but its efficacy is limited when used alone. Combining BC with other antibiotics enhances its antimicrobial properties synergistically. Our research aims to improve BC's solubility in glycerol, enabling better dissolution in aqueous media without toxic co-solvents using Minimum inhibitory concentration (MIC) assay and solubility tests. This enhancement will optimize BC's therapeutic potential against nosocomial infections, providing valuable insights for more efficient treatment strategies. Sample Average rate (abs/hrs) STDEV control 0.309 0.006 (n=4) 5% Gly 0.259* 0.031 (n=4) 10% Gly 0.152 0.006 (n=2) 15% Gly 0.023# 0.015 (n=3) Table 1. Average growth rate of E. coli C600. Table 2. Solubility of BC in Gly, Water, and LB. y = 0.0147x + 0.0036 R2 = 0.9997 Results Figure 2. MIC assay to determine the effect of varying concentrations of Glycerol on E. coli C600. 0-70% glycerol was mixed with 10-3 diluted bacteria in a 96-well microplate incubated at 600 nm and 30OC for 20 hours in a Varioskan Lux machine. Solvent mass (mg) of BC added to 5 mL solvent Concentration of dissolved BC (mg/mL) Gly 101.6 14.45 Water 100.5 1.87 LB 100.7 0.06 Solvent mass (mg) of BC added to 5 mL solvent Concentration of dissolved BC (mg/mL) 5% Gly + LB 100.8 0.12 10% Gly + LB 100.2 0.11 15% Gly + LB 100.1 0.19 Table 3. Solubility of BC in 5, 10, and 15% Gly including LB. The solubility of BC in 5, 10, and 15% glycerol-LB mixture