ANTIBACTERIAL ACTIVITIES OF PSIDIUM GUAJAVA LINN LEAF-MEDIATED BIOSYNTHESIZED SILVER NANOPARTICLES AGAINST METALLO BETA-LACTAMASE-PRODUCING PSEUDOMONAS AERUGINOSA ISOLATES

This study reports the biogenic synthesis of silver nanoparticles using methanolic extracts from Psidium guajava Linn leaf and evaluation of their antibacterial potentials against metallo β-lactamase-producing Pseudomonas aeruginosa isolates using agar well diffusion method. Phytochemicals such as saponins, alkaloids, tannins, phenols and flavonoids were detected in the crude extracts. The biosynthesized AgNPs were analyzed using UV-Vis specroscopy, Fourier-transofrm infrared spectroscopy (FTIR), scanning elctron microscopy and dynamic light scattering (DLS). The extract mediated particles were deep brown in colour with maximum absorbance at wavelength 408 nm. The synthesized particles were spherical in shapes, less aggregated with size ranges from 10 – 50 nm and FTIR revealed that AgNPs contained alkanes, esters and alcohol functional groups. The AgNPs exhibited better antibacterial properties at higher concentration with the zones of inhibition produced at 100 µg/mL ranging from 10.80±0.20 mm to 18.30±0.20 mm while at 25 µg/mL, zones of inhibition ranged from 11.00±0.20 mm to 14.00±0.20. The MIC of the AgNPs against the metallo β-lactamase-producing Pseudomonas aeruginosa isolates was 25 µg/mL, The results of the findings therefore suggests that extract biosynthesized particles have enhanced antibacterial activities against metallo β-lactamase-producing Pseudomonas aeruginosa compared to the crude extracts. Data generated implies that Psidium guajava Linn leaf extract mediated silver nanoparticles could a source of antibacterial agent for infections caused by metallo β-lactamase-producing Pseudomonas aeruginosa.