ANTIBACTERIAL ACTIVITY OF THE LEAF FRACTIONS OF ALCHORNEA CORDIFOLIA AGAINST ISOLATES FROM PATIENTS WITH RESPIRATORY TRACT INFECTION IN AHMADU BELLO UNIVERSITY TEACHING HOSPITAL ZARIA, NIGERIA
Yusuf I.*, Tytler B. A., Olayinka A. T. and Adeshina G. O.
Background: Recent years have witnessed a dramatic increase in antibacterial resistance and a decline in the development of novel antibiotics. This problem is prevalent among common etiologic pathogens associated with Respiratory Tract Infections. The aim of this study is to determine the antibacterial activity of the leaf fractions of Alchornea cordifolia against isolates from patients with respiratory tract infections. Methodology:The aqueous extract of Alchornea cordifolia leaf was fractionated using column chromatography. Thin layer Chromatography method was used to identify similar fractions. Agar-dilution method was employed to determine the Minimum Inhibitory Concentration(M.I.C) and Minimum Bactericidal Concentration (M.B.C) of fractions. Spread plate method was employed to determine the rate of kill of most active fraction. Result:The fractionation of the aqueous extract gave thirty five (35) fractions but after pooling together of similar ones, Seven (7) different fractions were obtained. Seventeen (17) bacteria species were isolated from samples of patients with respiratory tract infections and the isolates were identified as;Staphylococcus aureus (7), Streptococcus spp. (5), Pseudomonas aeruginosa (2), Klebsiella pneumoniae (2), and Escherichia coli (1). The M.I.C of the fractions showed that F2 had the lowest M.I.C values against all the isolates. The F2 fraction had M.I.C values that ranged between 2.5 – 5 mg/ml against S. aureus and 5 – 10 mg/ml against Strep. spp. The death/survival rate showed that at 1440 minutes, M.I.C concentration of 2.5 mg/ml of F2 had 100 % kill; there was reduction in surviving cells with both the Sub-M.I.C concentration of 1.25 mg/ml and amoxicillin clavulanic acid 30 μg/ml against S. aureus (T38) isolate. A total kill was observed at 240 minutes, with M.I.C concentration of 5 mg/ml and at 1440 minutes, with Sub-M.I.C concentration of 2.5 mg/ml against Klebsiella pneumoniae (S16). Discussion: The observed low M.I.C values from fraction F2 could be due to the fact that F2 contains the secondary metabolites responsible for the superior antibacterial activity of the aqueous extract. The lower M.I.C confirm the high activity of fraction (F2) at low concentration. High activity of antibacterial agent at low concentration is very essential for chemotherapeutic purposes because of their toxicity to patient system. References:Smith, R. P., Paxman, J. J., Scanlon, M. J., Heras, B. (2016). Targetting bacterial Dsb protein for the development of anti-virulence agent. Molecules. 21: 811 CLSI, (2006). Method for dilution antimicrobial susceptibility test for bacteria that grow aerobically. Wayne, Pa, USA. Approved standard M7-A7.
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