Evaluation of the Antimicrobial and Antibiofilm Effect of Vitamin C and Ceftriaxone Against Uropathogenic Escherichia coli

Abstract

     Urinary tract infections (UTIs) are among the most common bacterial infections, with Escherichia coli accounting for the predominant uropathogen, posing a significant challenge in healthcare and treatment. This study investigates biofilm formation, antibiotic resistance, and the impact of vitamin C, Ceftriaxone, and their combination on uropathogenic Escherichia coli (UPEC). Twenty multi-drug (MDR) isolates were obtained from hospitals in Baghdad; the isolates were identified and confirmed using the VITEK® 2 Compact system. The biofilm assay showed that the isolates formed biofilms. Minimum inhibitory concentration (MIC) testing revealed high ceftriaxone resistance, whereas most isolates exhibited inhibition at varying concentrations. Three strong biofilm-forming isolates, with the highest Ceftriaxone MICs, were screened for biofilm-related genes (sfa, afa, and fimH) via PCR, confirming their presence. Sub-MIC concentrations of vitamin C decreased biofilm formation, while sub-MIC concentrations of Ceftriaxone unexpectedly enhanced biofilm production. Gene expression analysis by RT-PCR showed that vitamin C downregulated afa and fimH, but upregulated sfa in one isolate. Ceftriaxone alone variably affected gene expression, whereas its combination with vitamin C produced inconsistent synergistic effects, sometimes increasing sfa expression. These findings emphasize the strain-specific responses of UPEC to vitamin C and Ceftriaxone, underscoring the need for caution when considering vitamin C as a therapeutic adjunct in UTI treatment.