Inhibitory effects of alcoholic extracts of thyme on verotoxin pruduction of entro heorrhagic Escherichia coli o157:h7

Entrohemorrhagic Escherichia coli is a human pathogen that causes hemorrhagic colitis due to its verotoxin. It is an agent with food poisoning importance; a significant number of cases subsequntly develop hemolitic uremic syndrome (HUS) which is probably the most common cause of renal failure in childeren and occasionally resulting in death. Inhibition of bacterial growth in food is the most important factor in prevention. Rate of heating, incubating temperature and type of substances in food cooking are important factors to control the microbial contamination. Since a long time ago, plants also have been applied in food compounds for their preservative and flavor characteristics. In this research, the inhibitory effect of thyme alcoholic extract on verotoxin production of Entrohemorrhagic Escherichia coli was examined. Thyme plant from natural resource research center of Tehran was provided and Entrohemorrhagic Escherichia Coli (ATCC 42889) was provided from Boo-Ali reference laboratory. After providing of alcoholic extract of plant (10% w/v) the effect of extract against Entrohemorrhagic Escherichia coli was studied by cylinder plate method (40 µl) and broth tube (contained extracts) and verotoxin production in sub inhibitory concentrations with VTEC-RPLA (Reserve passive Latex Agglutination) was examined. Experiments were repeated three times. Results were documented by Mean diameter of inhibitory zones and number of cfu. The most effect in cylinder plate method was observed in marsh and cumin extracts. Result showed that MIC and MBC of Alcoholic thyme extract for EHEC were 1/64 (780 µg/ml) While diluted 1/128 (390 µg/ml) inhibited verotoxin production. The finding results indicate that this plant can be used as a food flavor to affect the growth and verotoxin production of Entrohemorrhagic Escherichia coli and as a food preservative instead of chemical substances.