Biochemical Characterization and Molecular Identification of Escherichia coli Isolate from Abattoir Wastes and Its Susceptibility to Ethanolic Root Extract of Azadirachta indica (neem)

Abstract

Aim: The study evaluates the molecular identification of Escherichia coli isolate from abattoir wastes and its susceptibility to ethanolic root extract of Azadirachta indica (neem). Methodology: The isolation, cultural characterization and identification of Escherichia coli isolate using biochemical methods and molecular identification (polymerase chain reaction)  were carried out using standard methods. Gas Chromatography-Mass Spectrometry (GC-MS) and phytochemical analysis of the ethanolic root extract of Azadirachta indica (neem) were determined using standard methods. Antibacterial activities were determined by disc diffusion and agar well diffusion methods. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined using standard procedures.  Results: The result of the phytochemical screening shows that the plant contains phenolic       compounds, flavonoids, carbohydrate, alkaloids, saponins, tannin and cardiac glycosides. forty compounds were identified in the root of A. indica using GC-MS analysis with 9-Octadecenoic acid, (E)- being the most abundant with peak area of 28.13% and retention time of 22.044. The organism was confirmed to be Escherichia coli using polymerase chain reaction with specific primer pairs and later resolved in an agarose gel electrophoresis for 16S rRNA gene with band size of 253 base pair. The organism was susceptible to gentamycin, amoxicillin, pefloxacin, sparfloxacin and resistant to tarivid with weak response. The study shows that ethanolic root extract of A. indica exhibited strong response antimicrobial activity against Escherichia coli with zone of inhibition of 19.48±0.23 and 21.36±0.54 at concentration of 250 and 500 mg/dl respectively. At 100 mg/ml, the extract showed little or no response with zone of inhibition of 9.33±0.33. Azithromycin solution at 12.50 and 25.00 mg/ml showed strong response and potent response against E. coli with zone of inhibition of 23.37±0.48 and 37.34±0.65 respectively. At 5.00 mg/ml, azithromycin antibiotic exhibited weak response against E. coli with zone of inhibition of 15.37 ± 0.33. The ethanolic root extract of A. indica and azithromycin solution have MIC and MBC values of 31.25, 15.63, 62.50 and 31.25 mg/ml respectively against E. coli. The ethanolic root extract of A. indica was bactericidal with MBC/MIC ratio of 2.00. The plant has antimicrobial activity against Escherichia coli and may prevent pathogenic diseases caused by the organism. Conclusions: The root of Azadirachta indica (neem) contains phytochemicals, possesses antibacterial activity and may prevent pathogenic diseases caused by Escherichia coli.