Evaluation of the Role of Antioxidant Vitamin C in Reversal of Antimicrobial Agent (Amoxicillin) Resistance

Objectives: To evaluate the potential of Vitamin C in reversing microbial resistance to amoxicillin in Escherichia coli strains (CFT073) by exploring its antioxidant property as a modulator of antibiotic efficacy. Methods: An in vitro study was conducted using amoxicillin-resistant E. coli (CFT073) isolates. The antimicrobial effects of amoxicillin alone, Vitamin C alone (5 mg/mL and 10 mg/mL), and combinations of amoxicillin with Vitamin C were tested. The zone of inhibition was measured on Day 1, Day 3, and Day 5 to assess antibacterial activity. Statistical analysis was performed using Student’s t-test. Results: Vitamin C alone, at both concentrations, did not exhibit any inhibitory effect. Amoxicillin alone did not produce inhibition. The combination of amoxicillin with Vitamin C at 5 mg/mL and 10 mg/mL enhanced the antibacterial activity significantly, with zones of inhibition measuring 14.8±0.92 mm and 16.2±0.93 mm, respectively (p<0.05). Conclusion: Vitamin C, when combined with amoxicillin, significantly increased the susceptibility of resistant E. coli strains by potentially reducing oxidative stress. Vitamin C, being safe, inexpensive, and widely available, could serve as an effective adjuvant in antimicrobial therapy.