Screening of desert plants for use against bacterial pathogens in fish

The antibacterial activity of aqueous extracts of 104 desert plant species was studied on the following fish bacterial pathogens: Aeromonas hydrophila, Photobacterium damselae subspecies piscicida, Streptococcus iniae, and Vibrio alginolyticus. Seventeen plant species had antibacterial activity, as identified by disk diffusion assay. The pathogen P. damselae was sensitive to all 17 active extracts except Peganum harmala and a high inhibitory effect (14-19.5 mm) was produced by Anchusa strigosa, Hammada scoparia, Achillea fragrantissima, Pulicaria crispa and Loranthus acaciae. The pathogens A. hydrophila and V. alginolyticus were inhibited by H. scoparia, L. acaciae, and P. harmala (7-20.5 mm). The pathogen S. iniae was inhibited by Ochradenus baccatus and Reseda stenostachya (10.5 mm). The benefits of using desert plants as an alternative to conventional antibiotics are discussed.