Prevalence of tir Gene in E. coli Strain Isolated from Cold Foods

E. coli resides in natural intestinal tract of human and warm blooded animals. This bacteria can be transferred (fecal, oral) into cold foods like salad, cold sandwich that are not heated and infect other people. In this research, using enriched and isolated culture media (e.g. nutrient broth and MacConkey agar and EMB agar) and performing biochemical experiments (e.g. sugars fermentation, movement and Andole and etc.) as well as molecular method PCR, it was cleared that only 25 samples out of collected 100 cold food samples (e.g. lettuce, sausage, cabbage and tomato) had E. coli bacteria and tir gene in this bacterium have tir gene suggesting that pathogenic bacteria E. coli is in 25 (25%) samples. From between collected 100 cold food samples (25 lettuce, 25 sausage, 25 cabbage and 25 tomato) cultured samples in the isolated culture media and Direct PCR experiment indicated that just 25 samples (25%) sausage have tir gene. Samples sausage have tir gene. In fact, the results of cultivation and without cultivation (directly) were similar in PCR and in PCR from samples from cultivation and without cultivation, 25% tir gene has been observed. This research indicated that the gene tir can be identified using direct PCR in cold foods used in cold sandwich and salads in a shorter time (24 h) compared to cultures in isolated media and biochemical experiments. The presence of tir in the collected samples indicates the pathogenicity of the bacterium E. coli. Therefore, earlier identification of this gene through molecular method PCR can result in distinguished pathogenic Escherichia coli.