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|Title: ||Antimicrobial Activity of Selected Plant Species and Antibiotic Drugs against Escherichia Coli O157:H7|
|Authors: ||Itelima, J. U.|
Agina, S. E.
Pandukur, S. G.
|Keywords: ||in vitro|
|Issue Date: ||2017|
|Publisher: ||African Journal of Microbiology Research|
|Series/Report no.: ||Vol. 11;No. 20; Pp 793-803|
|Abstract: ||Recent research has focused on natural plant products as alternative for disease control in both
developed and developing countries. Medicinal plants can be a possible source for new potent
antimicrobial agents to which pathogenic strains are not resistant. The present study was carried out to
determine the in vitro antimicrobial activity of 14 plant species namely; Allium sativum, Aloe vera,
Bryophyllum pinnatum, Cassia ocidentalis, Citrus sinensis, Euphorbia hirta, Mangifera indica, Myristica
fragrans, Ocimium gratissimum, Piper guineese, Psidium guajava, Spermacoce verticilata, Vernonia
amygdalina and Zingiber officinale and 3 antibiotic drugs namely; ampicillin, ciprofloxacin and
streptomycin on Escherichia coli O157:H7 isolated from human clinical sample. The extracts of the
plant species were prepared by cold percolation method using ethanol and water as solvents.
Phytochemical analyses of the extracts of the different plant species were determined using standard
methods. Agar well diffusion method was used to evaluate the antimicrobial sensitivity test of the plant
extracts and that of antibiotic drugs at different concentrations ranging from 31.25 to 500 mg/ml. The
minimum inhibitory concentration (MIC) of the antimicrobial agents against Escherichia coli O157:H7
was also conducted. Phytochemical analyses of the plant species revealed the presence of bioactivity
principle such as alkaloids, balsam, cardiac glucoside, flavonoids, phenols, resins, saponins, tannins,
terpenes and steroids. The results showed that all the antimicrobial agents exhibited inhibitory effects
against the growth of the bacterial isolate at various degrees. Among the plant species employed in the
study, the ethanolic and water extracts of P. guajava showed the highest inhibitory effect against the
bacterium with growth inhibition mean zone diameters of 29.9 and 26.0 mm respectively at 500 mg/ml.
Following P. guagava in order of inhibitory effect against E. coli O157:H7 are ethanolic extracts A.
sativum, Z. officinale, V. amygdalina and M. indica with mean zones of inhibition of 21.2, 20.8, 20.3 and
19.9 mm respectively at 500 mg/ml. The results also revealed that of the three antibiotic drugs used in
the study, ciprofloxacin exhibited the highest inhibitory effect against the organism with zone of
inhibition of 38.6 mm, followed by streptomycin 30.2 mm, while ampicilin had the least 22.3 mm. The
MIC results reveal that some of the plant species showed similar inhibitory effect against the bacterium,
while the MIC results of the rest of the plants varied from one another. The in vitro study of the
antimicrobial activity of the extracts of the various plant species and that of the antibiotic drugs against
E. coli O157:H7 has demonstrated that certain folk medicine can be as effective as modern medicine in
combating pathogenic microorganisms|
|Appears in Collections:||Plant Science and Biotechnology|
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