In Vitro Growth-Inhibitory Activity of Non Antibiotic Agents Toward Methicillin-Resistant S. Aureus and Esbl-Producing Escherichia Coli

Abstract

Antibiotic resistance has become a major global health concern, particularly due to the increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. The exploration of non-antibiotic agents with antibacterial properties offers a potential alternative approach for addressing resistant bacterial infections. This study aimed to evaluate the antibacterial activity of N-acetylcysteine (NAC), ascorbic acid (vitamin C), and diclofenac against MRSA and ESBL-producing E. coli. This experimental laboratory study employed a randomized post-test-only control group design. Clinical isolates of MRSA and ESBL-producing E. coli were evaluated. The bacterial strains were treated with various concentrations (100%, 50%, 25%, 12.5%, and 6.25%) of NAC (initial concentration: 200 mg/mL), vitamin C (initial concentration: 200 mg/mL), and sodium diclofenac (initial concentration: 25 mg/mL). Antibacterial activity was assessed using the microdilution method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).Diclofenac demonstrated the strongest antibacterial activity, with MIC and MBC values of 3.125 mg/dL against MRSA and 6.25 mg/dL against ESBL-producing E. coli. NAC showed moderate antibacterial activity, exhibiting bactericidal effects against E. coli (MIC/MBC: 100 mg/dL) but limited activity against MRSA (MIC: 200 mg/dL; MBC: >200 mg/dL). Vitamin C demonstrated the weakest antibacterial activity, showing bactericidal effects only against E. coli at 200 mg/dL and no bactericidal effect against MRSA. NAC, vitamin C, and sodium diclofenac demonstrated antibacterial activity against MRSA and ESBL-producing E. coli. Among the three tested agents, sodium diclofenac exhibited the strongest antibacterial activity, suggesting its potential role as an adjunctive agent in future investigations of strategies for managing resistant bacterial infections.