Evaluation of antibacterial activity of medicinal plant extracts against clinical isolates of pathogens from children with acute gastroenteritis at Katutura State Hospital¸ Windhoek, Namibia

  • Albertina M.N. Iikasha
  • Isaac K. Quaye
  • Davis R. Mumbengegwi
Keywords: Acute Diarrhea, Medicinal Plants, Antibacterial, Resistance, Minimum Inhibitory Concentration.


Background: Diarrhea is a major health concern in Namibia with an estimate of 17000 cases in 2015 in Omusati and Kunene regions. The present study aimed at isolating and identifying gastrointestinal bacteria from stool samples of children admitted at Katutura hospital, Windhoek, and to determine the efficacy of selected medicinal plants used in treating gastroenteritis in Namibia.

Materials and Methods: Stool samples were collected for 6 months from children under age five admitted with acute diarrhea. Seeplex12 automated DNA extractor and PCR were used for isolation and identification of bacterial DNA from the samples. Serially diluted stool samples were cultured on selective media, sub-cultured in Nutrient broth and preserved in 80% glycerol. Parts of Boscia albitrunca, Ziziphus mucronata, Combretum apiculatum, Solanum linnaeanum and Terminalia sericea were collected, dried, ground and extracted using distilled water and ethanol. Disc diffusion method was used to determine the antibacterial activity of the plant extracts against isolated bacteria.

Results: A total of 12 out of the 18 stool samples collected had bacterial pathogens successfully identified by PCR. 33.3% were positive for Salmonella, 11.1% for E. coli 157:H7 VTEC and 22.2% for E.coli H7. C. apiculatum organic extracts exhibited potent antibacterial activity of (16±  0.57mm) at 1000 μg/ml against Shigella and Salmonella with a moderate minimum inhibitory concentration (MIC) of 250 μg/ml against  Salmonella. Salmonella and Shigella showed resistance to 10 μg/ml of ampicillin.

Conclusion: Plant extracts showed in vitro antibacterial activity. However, toxicology and in vivo efficacy of these plant extracts should be  determined before recommending their mainstream uses.

Key words: Acute Diarrhea, Medicinal Plants, Antibacterial, Resistance, Minimum Inhibitory Concentration.


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eISSN: 0189-6016