In vitro Antibacterial Activity of Vitamin C and in Combination with Ciprofloxacin against Uropathogenic Escherichia coli

Abstract

Introduction: Multidrug Resistant (MDR) bacteria have become a major cause for concern; there has been limited success in the search for newer antibiotics. The search for options has led researchers to vitamin C, an unlikely ally. Its antibacterial effects on Staphylococcus aureus, Mycobacterium tuberculosis, and Escherichia coli (E. coli) have been documented. It can also enhance the action of antibiotics such as levofloxacin. Aim: This study aims to analyse the inhibitory effects of vitamin C alone and in combination with ciprofloxacin against E. coli. Materials and Methods: Present laboratory based prospective study was conducted at Department of Microbiology, Pondicherry Institute of Medical Sciences, Puducherry, India. A total 50 isolates of E. coli from urine samples sent between August to September 2016 were inoculated in media containing vitamin C (ascorbic acid and sodium ascorbate) in concentrations of 5 mg/mL, 10 mg/mL both alone and in combination with ciprofloxacin (1 µg/mL). After overnight incubation, absorbance was measured by spectrophotometry at 450 nm. Mean absorbance at each concentration was calculated. Unpaired t-test and multivariate analysis by ANOVA were used to compare mean absorbance of isolates. A p-value <0.05 was considered as statistically significant. Results: Absorbance values of bacterial solutions revealed a decreasing trend as vitamin C concentration was increased. The combination of vitamin C and ciprofloxacin produced no statistically significant drop in the absorbance (p-value=1). Conclusion: Ascorbic acid did not show any synergistic action in combination with ciprofloxacin when tested on uropathogenic E. coli. However when tested alone, ascorbic acid significantly inhibited the growth of E. coli.

Keywords

• ascorbic acid
• quinolone
• sodium ascorbate
• uropathogen