Introduction: Bacterial resistance to antibiotics is a global problem. Thus, discovery of newer antibacterial agents is always necessary. As a result of this problem, researchers are usually focusing on natural products to develop better medications against drug- resistant microbial strains. This study aimed to investigate the antibacterial activity of Scrophularia striataa gainst standard and clinical isolates of Escherichia coli.

Materials & methods: Ethanol, cold water and hot water extracts of S. striata were carried out by using soxhlet apparatus. Minimum Inhibitory Concentration (MIC) and Minimum Bacterial Concentration (MBC) of plant extracts were determined in six different concentrations (25, 50-100-200-400-800 mg/ml) using disk-diffusion agar method and the dilution method. The antibiotics amikacin and gentamicin as a positive control and DMSO was used as negative control.

Findings: The results obtained from the cold water extract of this plant have no antimicrobial effect on standard and clinical strains. Ethanol extract at concentrations of 800 and 400 mg/ml and boiling water extract a tall concentrations had antimicrobial effect. Spread on agar disk diffusion method has a significant inhibitory effect on the E.coli. MIC and MBC were 100 and 400 mg respectively.

Discussion & Conclusions: Methanol and hot water extracts of this plant inhibited growth of pathogenic bacteria. Clinical applications of these materials needed further investigations.