Résumé
The present work was carried out to study bacterial pathogens isolated from wheat field water and also effect of some plant extracts on these bacterial pathogens. Five bacterial strains were isolated from wheat field water. Different morphological and biochemical tests were performed to identify and characterize bacterial pathogens. Among isolated strains two belonged to genus Staphylococcus sp., other two were Pseudomonas spp. and one strain belonged to genus Salmonella sp. Effect of various parameters such as temperature, pH, antibiotics and heavy metals of these pathogens were also studied. Optimum temperature for all bacterial strains was 37°C and optimum pH was 7 except strain 3 which had pH 6. Different antibiotics with different potency were applied to check the resistance of bacterial strains against them. Among these antibiotics Cloxacillin and Teicoplanin were most potent while Oxacillin was as less potent antibiotic because three bacterial strains were resistant against it. While remaining antibiotics proved as potent. Seven heavy metals which were zinc [Zn[+2]], copper [Cu[+2]], Ferrous [Fe[+2]], mercury [Hg[+2]], Nickel [Ni[+2]], chromium [Cr[+2]]and cobalt [Co[+2]] with different concentrations were applied to bacterial strains. Minimum inhibitory concentration of heavy metals for all bacterial was different. Different plant extracts [Artemezia incise, Colebrookia oppositifolia, Rhynchosia pseudocajan] checked for their antibacterial activity against these pathogens. These plant extracts showed antibacterial activity against antibiotic and metal resistant bacterial isolates