A STUDY OF COMBINED EFFECTS OF ANTIBIOTIC AND PLANT EXTRACTS AGAINST CORYNEBACTERIUM DIPHTHERIAE ISOLATED FROM UPPER RESPIRATORY TRACT

Abstract

The development of antimicrobial resistance (AMR) in Corynebacterium diphtheriae, including multidrug-resistant and toxigenic strains, requires new therapeutic approaches. Plant-based compounds are a potential source of synergistic agents to boost conventional antibiotics. This paper examined the synergetic effect of antibiotics and Musa acuminata (banana) peel extracts against clinical isolates of C. diphtheriae. A total of 23 confirmed C. diphtheriae isolates from the upper respiratory tract were used in an experimental study. Banana peels were dried, and bioactive compounds were extracted by ethanol and hexane solvents. Antibiotic susceptibility was tested by the disk diffusion method against a panel of antibiotics. The antibacterial activity of individual extracts and the synergistic effect of antibiotics was determined by the agar well diffusion method. There is a high level of antibiotic resistance, especially to sulphonamide (35.8%), clindamycin (46.2%), and ciprofloxacin (29.9%). Tetracycline (86.2%) and erythromycin (88.9%) were the most effective. The ethanolic extract of banana peel had a better antibacterial effect (22.5 mm zone of inhibition) than the hexane extract (18 mm). Synergy testing showed a significant enhancing effect of the ethanolic extract, especially with erythromycin (98.9% improvement) and tetracycline (91.1% improvement). In comparison, there were very low synergistic effects with penicillin (17.5%) and ciprofloxacin (32%). Ethanolic extract of banana peel has good antibacterial activity against C. diphtheriae and shows a good synergistic effect with erythromycin and tetracycline. This combination therapy offers a potential solution to the fight against antibiotic-resistant diphtheria infection, which valorizes agricultural waste for pharmaceutical use