The most sensitive bacteria against extract concentrations were Bacillus subtilis, Bacillus cereus and Mycobacterium smegmatis. In addition, E. coli O157:H7 shown resistance against effect of Istanbul thyme extract. While the most sensitive microorganism against Karabas thyme extract had Mycobacterium smegmatis, Yersiniae enterocolitica shown strong resistance. The inhibitory effect of extracts changed depending on concentrations. Most sensitive bacteria against extract concentration had Gram (+) bacteria that Mycobacterium smegmatis, Bacillus subtilis and Bacillus cereus. The most resistant bacteria is Gram (-) bacteria, E. coli O157: H7, Klebsiella pneumoniae, Staphylococcus aureus and Yersiniae enterocolitica were found. Generally, antibacterial effects of Istanbul extracts obtained by different application and extraction systems were found partly high compared with effects of Karabas thyme extracts.