Synergistic and antagonistic effects of vinegar and sodium bicarbonate on antibiotic-resistant Escherichia coli

Escherichia coli with antimicrobial resistance has become a frequent global problem in recent decades, which makes it challenging to treat with conventional medicines. This study aimed to evaluate different strategies for managing microbial resistance. E. coli was isolated from wounds and the urinary tract infections and then cultured on blood agar, MacConkey agar and EMB media. The well diffusion method was used to evaluate the activity of vinegar (5%) alone and combined with three concentrations (5%, 10%, and 20%) of sodium bicarbonate (SBC). The diameter of the zone of inhibition was measured in millimeters. Statistical analyses were performed using Excel and the SPSS 26 software. Of the 24 E. coli isolates, approximately 66.6% were sensitive to vinegar combined with 5% SBC compared to 75% sensitivity to vinegar alone. Furthermore, 41.66% of the bacteria were sensitive to vinegar combined with 10% SBC. This study showed that 33.33% of the bacteria were sensitive to vinegar combined with 20% SBC. Comparison of the mean of the inhibition zone for vinegar 13 ± 6.04 mm alone with 20% SBC plus vinegar 7.83 ± 5.56 mm was significant (P = 0.01). Vinegar combined with 10% SBC had an inhibitory effect (antagonism) on the antibacterial activity of vinegar (P = 0.02). The antibacterial efficacy of vinegar with SBC decreased with increasing SBC concentrations, demonstrating an antagonistic effect owing to sodium acetate formation.