ANTIBACTERIAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST ESCHERICHIACOLI STRAINS ISOLATED FROM DIARRHOEIC STOOL OF CHILDREN IN NIGER STATE, NIGERIA

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Date
2021-04
Authors
MUHAMMAD, Isah Legbo
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Abstract
The study was carried out to determine the antibacterial activity of Entadaafricana, Ptericarpuserinaceus and Vitexdoniana extracts against Escherichia coli strains isolated from diarrhoeic stool of patients (0-5) years attending selected Hospitals in Niger State, Nigeria. The Hospitals include UmaruSanda General Hospital, Bida; General Hospital, Minna and General Hospital, Kontagora. A total of 480 stool samples were collected from diarrhoeal patients between February and October, 2014. The samples were cultured on MacConkey agar and Eosin Methylene Blue agar. The isolates obtained were Gram-stained, identified and serotyped using biochemical tests and Escherichia coliidentification strain kits. The phytochemical screening of Entadaafricana, Ptericarpuserinaceusand Vitexdoniana leaf and stem-bark extracts was evaluated using standard qualitative methods. Acute toxicity (LD50) was determined using oral administration method. The antibacterial activity of Entadaafricana, Ptericarpuserinaceusand Vitexdonianaleaf and stem-bark extracts were also evaluated using agar well diffusion method. The minimum inhibitory and minimum bactericidal concentration was evaluated using broth tube dilution and pour plating methods respectively. The work established a value of 16.9% of diarrhoeagenic Escherichia coli in the study area. Different strains of Escherichia coli associated with diarrhoeal patients that were isolated include Enteroaggregative Escherichia coli (n=16, 19.8%), Enterohaemorrhagic Escherichia coli (n=13, 16.1%), Enteroinvasive Escherichia coli (n=8, 9.9%), EnteropathogenicEscherichia coli (n=27, 33.3%) and EnterotoxigenicEscherichia coli (n= 17, 21.0%). Socio-demographic and risk factors found to be associated with diarrhoea in the study area were: age, area of domicile, occupation, educational status of parents, source of water and feeding pattern were statistically significant. The phytochemical screening of all the crude extracts were found to have anthraquinones, flavonoids, glycosides,saponins, steroids, tannins and resins except forPtericarpus erinaceousin which resins was not detected. The acute toxicity (LD50) of thethree plant extracts against albino rats wasgreater than5000mg/kg body weight could be safe for use in human or higher animals. The methanolic extracts ofEntadaafricana, Ptericarpuserinaceus and Vitexdoniana showed highest activity against Escherichia coli at 20mg/mL with zones of inhibition ranging between 20.00-36.00mm, 20.00- 30.00mm and 24.00-38.00mm respectively.The methanolic leaf fraction of Vitexdonianahad the highest activity against all the testedEscherichia coli strain except Enteroinvasive Escherichia coli which had 50% susceptibility. The Vitexdoniana aqueous stem-bark fraction with minimum inhibitory concentration (MIC) and minimum bactericidal concentration(MBC) values of 5.0 and 10.0mg/mL emerged as the active fraction against 75% of the EAEC, while methanolic leaf fraction had MIC and MBC values of 5.0 and 10mg/mL against 77% of the EHEC. The aqueous leaf fraction had MIC and MBC values of 10mg/mL against 62.5% of the EIEC, while methanolic leaf fraction had MIC and MBC values of 5.0 and 10mg/mL against 61% and 81% of the EPEC. The methanolic stem-bark fraction exhibited highest activity with MIC and MBC values of 5.0 and 10mg/mL against 79% and 100% of the EnterotoxigenicEscherichia coli.The extracts of the plants could be promoted for search of new leads against enterobacterial pathogens having MIC values of 5.0-20mg/mL. The result has justified their utilization by traditional medicine practitioners for the treatment of diarrhoea and other related ailments associated with Escherichia coli strains.
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A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DOCTOR OF PHILOSOPHY (Ph.D) DEGREE IN MICROBIOLOGY DEPARTMENT OF MICROBIOLOGY, FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA
Keywords
ANTIBACTERIAL ACTIVITY,, SELECTED MEDICINAL PLANT,, ESCHERICHIACOLI STRAINS ISOLATED,, DIARRHOEIC STOOL,, CHILDREN,, NIGER STATE,, NIGERIA
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