Antimicrobial activity of Vitamin C demonstrated on uropathogenic Escherichia coli and Klebsiella pneumoniae

Abstract

Purpose: Studies have demonstrated the ability of Vitamin C (ascorbic acid) to inhibit pathogenic bacteria and inhibit biofilms. The effect of varying concentrations of ascorbic acid on bacterial growth was studied on uropathogenic Escherichia coli and Klebsiella pneumoniae. The concentration at which maximal inhibition occurred was determined. Methods: All uropathogenic strains of E. coli and K. pneumoniae isolated from patients over a 3-month period were incubated in varying concentrations (5, 10 and 20 mg/ml) of Vitamin C-supplemented Trypticase Soy Broth. Effect on bacterial growth was quantified as a change in absorbance measured by spectrophotometry (450 nm), as compared to controls. Independent samples t-test was used to calculate P value. Results: Bacterial growth was inhibited at all Vitamin C concentrations. Mean absorbances of E. coli and K. pneumoniae broths containing 5, 10, and 20 mg/ml Vitamin C were significantly less than absorbances of growth control broths without Vitamin C (P 0.005). Thus, the inhibitory activity of Vitamin C appears to be dose-dependent, with 10 mg/ml being the optimum concentration of ascorbic acid. Conclusions: Ascorbic acid's ability to inhibit bacterial growth may find novel clinical applications. Vitamin C may find potential use in topical antibacterial applications, or urinary bladder irrigation fluid for catheterized patients with urinary tract infections or during bladder instrumentation. There is a need to further explore the possibility of using Vitamin C safely as an effective antimicrobial agent.