Synergistic Effects of Medicinal Plants Carica papaya, Telferia ocidentalis and Oxytetracyline against some Pathogens Isolated from Clarias Gariepinus

Abstract

The problem of fish diseases may be due to the development of antibiotic-resistant bacteria and there is an increasing awareness to determine the efficacy of plants as an alternative to treat microbial diseases of aquatic animals. Antibacterial and antifungal synergistic evaluation of methanolic and ethanolic extracts of Fluted Pumpkin Leaves (FPL), Pawpaw Leaves (PL) and combination with oxytetracycline were investigated using the agar cup diffusion and broth diffusion techniques. The extracts were tested against 8 clinical strains of Gram-positive and Gram-negative bacteria and a fungal. Minimum Inhibitory Concentration (MIC) of methanolic and ethanolic extracts of pumpkin, pawpaw leaves and combination with oxytetracycline were determined using standard methods. Data were analyzed using descriptive statistics. The extracts displayed higher antimicrobial properties to the Gram-positive and G negative bacteria and these plants inhibited the growth of all the microorganisms used in the study when combine with oxytetracycline at 10 mg/ml and 30 mg/ml. The diameter of the zone of inhibition of methanolic and ethanolic extracts of fluted pumpkin and pawpaw leaves when combine with oxytetracycline (10 mg/ml and 30 mg/ml) were higher than single application and combination of the two plants with oxytetracycline. The combination of extracts of each plant with oxytetracycline was found to be the most effective combination in retarding microbial growth of all tested pathogenic bacteria The results of MIC of methanolic and ethanolic extracts of pawpaw leaves, fluted pumpkin leaves and oxytetracycline at 10 mg/ml and 30 mg/ml range between 212.5 µg/ml - 850 µg/ml while the control doesn’t show any antimicrobial properties in terms of zone of inhibition and minimum inhibitory concentration. The results observed in the pumpkin and pawpaw leaves and combination with oxytetracycline can provide additive or synergistic inhibitory effects making them more effective as antimicrobial agents against fish pathogens.