Antibacterial Activity Of Anonna Muricata (Soursop) Leaves Extracts On Urogenital Isolates Of Enterococcus Faecalis From Patients Attending A Tertiary Hospital In Calabar, Nigeria

Annona (A.) muricata leaves extracts were evaluated for antibacterial activity against urogenital isolates of Enterococcus (E.) faecalis obtained from University of Calabar Teaching Hospital, Calabar, Nigeria. Ethanol and aqueous extracts of A. muricata leaves were prepared by Soxhlet extraction method, and tested for antibacterial activity against 20 pre-identified isolates of E. faecalis using agar-well diffusion method. Minimum Inhibitory Concentration (MIC) of the extracts was determined using broth dilution method. Antibiotic susceptibility of the isolates was determined using Kirby-Bauer disc diffusion method. Both extracts of A. muricata leaves produced significant, concentration-dependent, antibacterial activity against E. faecalis isolates with MIC of 50 mg/ml (p= 0.0032). The ethanol extract showed a higher efficacy and inhibited more isolates [12(60%)] than the aqueous extract [10(50%)], with a mean inhibition-zone diameter of 16.5 ± 2.3 mm and 15.0 ± 1.0 mm, respectively. The size of the inhibition-zones correlated significantly, in direct proportion, with concentrations of the extracts (p= 0.012). The efficacy of the ethanol and aqueous extracts was lower than that of Ciprofloxacin (90%), Levofloxacin (80%), and Meropenem (65%), but corresponded with that of Cefoxitin (60%) and Gentamicin (55%), respectively. Identification and isolation of specific antimicrobial compounds present in A. muricata leaves crude extracts would likely optimize its potency against bacterial pathogens, such as E. faecalis, particularly multidrug resistant strains.