Antibacterial Activity of Some Plants of Traditional Herbal Medicine in Vitro against Escherichia Coli Originated from Liquid Pig Manure

The present study was designed to evaluate antimicrobial resistance of Escherichia coli (E.coli) isolated from liquid pig manure and to determine in vitro the antibacterial activity of nine traditional Latvian medical plants against various profiles of isolated antibiotic resistant E.coli. The commensal E.coli and extended-spectrum Beta-lactamase (ESBL)-producing E.coli isolates were tested to 12 antibiotics by the disk diffusion method. The in vitro antimicrobial activities of extracts of plants were evaluated, using well diffusion technique. Results showed that overall 72% of the E.coli isolates were antibiotic resistant, being divided into 55.5% resistant to up to three different classes of antibiotics and 44.5% resistant to four or more (up to 6) different classes. In the present study, majority of tested plants (Urtica dioica, Hypericum perforatum, Hippophae rhamnoides, Viburnum L., Vaccinium macrocarpon L., Cuminum cyminum L.) have not demonstrated antimicrobial activity to E.coli isolates. However, the oil extract of leaves of Plantago major, aqueous extract of green husk of Juglans regia L. and ethanol extract of seeds of Tropaeolum majus L. demonstrated activity against test cultures.