The Effect of Aqueous and Alcoholic Extracts of Thyme, Eucalyptus, Chamomile and Fennel on Virulence Factors of Escherichia Coli, Causative Agent of Urinary Tract Infection

Introduction: Escherichia coli is a gram negative bacilli and the most common cause of urinary tract infection especially in patients admitted to the hospital, the elderly and pregnant women. Nowadays, the excessive use of antibiotics has led to an ever-increasing prevalence of drug-resistant strains, and it seems that the spread of these strains is much faster than the discovery of new drugs. Medicinal herbs are a rich and valuable source of various compounds with antimicrobial properties and can be a good option for solving the problems of using antibiotics. The purpose of this study was to investigate the inhibitory effects of aqueous and alcoholic extracts of chamomile, thyme, fennel and eucalyptus on some pathogenic factors of Escherichia coli causative agent of urinary tract infection. Materials and Methods: In this study, the Escherichia coli bacterium was isolated from the urine specimen of patients with urinary tract infection and identified by biochemical methods. The effect of different dilutions of plant extracts on motility, hemolysin production and biofilm formation was investigated. MIC and MBC of extracts were investigated using disc diffusion method. Results: The results showed that, the alcoholic extract of thyme in three concentrations of 10, 5 and 2.5 mg/ml can prevent motility of the studied strain. Among the four plants studied, the alcoholic and aqueous extracts of thyme had the most effect in inhibiting the formation of biofilm. Alcoholic extract of thyme at concentration of 218.75 µg/ml and the alcoholic eucalyptus Extract at Concentration of 54.6875 µg/ml had inhibitory effects on the growth of bacterium, also the thyme alcoholic extract at concentration of 3500 μg / ml had bactericidal effect. None of the extracts had an effect on hemolysin production. Conclusion: Considering the inhibitory effect of thyme and eucalyptus alcoholic extracts on bacterial growth and the ability of these extracts to prevent biofilm formation and bacterial motility, these two herbs can be considered as the first choice for the treatment of urinary tract infections.