Objective: Recurrent Clostridium difficile infection (CDI) and the emergence of strains with reduced susceptibility to metronidazole and vancomycinwarrants alternative therapy. Hence, we tested the potential efficacy of the natural compound berberine hydrochloride (BBRHCl) against toxigenicC. difficile.Methods: Three representative polymerase chain reaction confirmed, toxin-positive strains were included in the study. Pulsed-field gel electrophoresis(PFGE) profile and antibiogram of the strains were analyzed along with 10 other toxin positive isolates. Efficacy of BBRHCl against toxigenic C. difficilewas determined using agar diffusion by punch well method.Results: PFGE grouped the test strains into three clusters with unique susceptibility pattern toward standard antibiotics. BBRHCl was efficaciousagainst the test strains at a concentration ranging between 6.25 μg/ml and 10 mg/ml. BBRHCl's breakpoint point inhibitory zone diameter wasequivalent (p<0.001) to the epidemiological cutoff values for teicoplanin, vancomycin and 2% black seed oil. Although the predicted concentration ofBBRHCl for breakpoint zone diameter equivalent to European Committee on Antimicrobial Susceptibility Testing's epidemiological cutoff value formetronidazole was observed to fall outside the tested concentration range; it was still within the safe dosage for humans.Conclusion: The present study is promising in considering BBRHCl as a potent substitute or adjunct not only for metronidazole, vancomycin andteicoplanin but also for natural compounds like 2% black seed oil for managing resistant cases of CDI. Owing to BBRHCl's direct antibacterial and antiinflammatoryaction, further investigations will aid in the proper characterization of the therapeutic effects of similar plant compounds, to developsafe and effective drugs against the epidemiological outbreak of CDI
