الملخص

Abstract The antibacterial activates of Quercus infectoria and Hibiscus sabdariffa extract were screened against Yersinia enterocolitica, Brucella melitensis, Listeria monocytogenes . Nutgalls of Quercus infectoria and calyces of Hibiscus sabdriffa were extracted in acetone using a Soxhlet apparatus. Extract of the plants showed high antibacterial activates on all types of bacteria tested using well diffusion method. The study also detecte the antibacterial effect to of some antibiotics using the disc diffusion method, The two extracts showed agood effect on Yersinia enterocolitica, the inhibition zone of nutgalls extract aganist this bacteria was (28)mm using the concentration (200) mg/cm3 which was greater than cephalexin, while the inhibition zone of Hibiscus sabdariffa extract was (20)mm using the same concentration which was greater than chloramphenicol.