Effect of Althaea officinalis Extract on Growth and Biofilm Formation in Pseudomonas aeruginosa

Pseudomonas aeruginosa is an important opportunistic pathogen that typically produces the biofilm. Biofilm- producing bacteria are inherently resistant to chemical treatment. This study examines the effect of Althaea officinalis extract on the biofilm formation by Pseudomonas aeruginosa. Antibiotic susceptibility test of Pseudomonas aeruginosa was performed by disk diffusion method and the effect of alcoholic extract of herb marshmallow (Althaea officinalis) was studied on bacteria. Hock extract collected from Northwest of Iran (Kurdistan) was prepared using soxhlet extractor. Antimicrobial properties of the extract were evaluated using well plates. Minimum inhibitory concentration (MIC) and minimal lethal concentration (MBC) of plant extracts and antibiotics were determined using CLSI standard plate. Biofilm formation was performed using a modified micro-titer plates. The MIC and MBC (62.5 mg D ml) showed significant effects of studied plants on the bacteria. Different concentrations of Althaea officinalis extract significantly reduced the biofilm produced by Pseudomonas aeruginosa in comparison with the positive control (P value = 0.0124). According to our findings, significant effect of this natural substance can be a promising agent in the treatment of Pseudomonas aeruginosa infection; and also an inhibitor of biofilm formation.