Abstract

Escherichia coli O157:H7 is a member of Enterobacteriaceae cocobacilla, which is gram negative and it causes gastrointestinal disease such as Diarrhea, Hemorrhagic colitis, and Hemolytic uremic. The first aim of this study was to examine E. coli O157:H7 in planktonic and biofilm state under stressed conditions of NaCl, pH, temperature and ORS (Oral Rehydration Salt) powder and then make comparisons. The second aim was to examine the shape of the bacterium in microscopic (bacteria shape) and macroscopic (bacterial colonies in Nutrient Agar culture media). Bacterial strains of E. coli O157:H7 were purchased (No. (NCTC) 12900). The bacteria were placed in liquid Nutrient Broth culture media and then transferred to Nutrient Agar culture media into plates to examine colonial shape. Microtitration plate was used in order to determine the biofilm formation under stressed conditions. Under these conditions, colonial morphology and bacterial shapes were significantly changed and their shapes tended to Cocci and Bacilli in order to survive more. Bacteria survival under stressed conditions was more in biofilm state rather than in Plankton state. This research demonstrated that E. coli O157: H7 had a different kind of effects in physicochemical stresses, while the optimal conditions were found in NaCl, pH, Tm and ORS stresses. (C) 2016 Friends Science Publishers