ANTIBACTERIAL ACTIVITIES OF NOTABLE ENDOPHYTIC BACTERIAL ISOLATED FROM LEAVES OF SPONDIAS MOMBIN

The antibacterial activities of endophytic bacteria isolated from the leaves of Spondias mombin were investigated. Fresh leaves of Spondias mombin were washed under running water and surface sterilized using 70% ethanol and 2% sodium hypochlorite solution. The sterilized leaves were cut into small pieces using a sterile blade and placed on nutrient agar before incubation for 24 hours. Pure isolates were subsequently transferred into nutrient broth to produce metabolites which were used in the antibacterial assay. A total of four (4) endophytic bacteria were isolated from the leaves of Spondias mombin and were identified as Micrococcus, Staphylococcus spp., Bacillus spp., and Fusobacterium. The agar well diffusion method was used to determine the sensitivity of the endophytic bacteria against selected test organisms which included Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Bacillus species. The results showed small zones of inhibition produced by the endophytic bacterial isolates against Klebsiella pneumoniae and Bacillus after 24 hours of incubation. Micrococcus produced a zone of inhibition of 3.5 mm against Bacillus and 4 mm against Klebsiella pneumoniae. Staphylococcus spp. produced inhibition zones of 5 mm against Bacillus and 2 mm against Klebsiella pneumoniae. Bacillus spp. produced inhibition zones of 2 mm against Bacillus and 6 mm against Klebsiella pneumoniae. Fusobacterium showed activity only against Klebsiella pneumoniae with a zone of inhibition of 6 mm. The highest zones of inhibition were recorded for Fusobacterium and Bacillus spp. against Klebsiella pneumoniae. Although these endophytic bacteria exhibited limited antibacterial activity against the selected test organisms, they may have potential applications in other relevant biological and medical fields.