The antibiofilm effects of some Cistus spp. against pathogenic microorganisms

Abstract

Recently, the potential antibacterial or antibiofilm effects of some plant species belonging to the Cistus sp. have motivated investigation of their use as herbal remedies. In this study, antibiofilm activities of aqueous (dH2O) leaf extracts of Cistus laurifolius L., C. creticus L. and C. salviifolius L. on some pathogenic microorganisms with biofilm forming ability were investigated. Biofilm forming ability of pathogen test microorganisms were evaluated by congo red agar method and microtiter plate method and all tested microorganisms were confirmed as biofilm producers. Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 11778, S. aureus ATCC 6538, P. aeruginosa ATCC 27853 and S. aureus ATCC 12600 were evaluated as strong biofilm producers. The highest concentration of examined extracts both showed biofilm inhibition and biofilm eradication against the tested pathogen microorganisms. In particular, studied plant extracts showed good antibiofilm effect, and biofilm eradication against S. aureus ATCC 6538 and S. aureus ATCC 12600. MBIC50 values of S. aureus ATCC 6538 were found as 6.25 µg/ml of C. laurifolius, and 50 µg/ml of C. creticus extracts. Also, 50 µg/ml of C. creticus extract showed ≥ 90% inhibition of biofilm growth (MBIC90 = 50 µg/ml). MBEC50 values of S. aureus ATCC 12600 were determined as 6.25 µg/ml in all tested plant extracts and 50 µg/ml of C. creticus extract was required to induce ≥ 90% eradication (MBEC90) of biofilm growth of S. aureus ATCC 12600. Our study revealed that aqueous leaf extracts of C. laurifolius, C. creticus and C. salviifolius could be potential candidates for drug discovery to treat pathogen test microorganisms capable to induce infectious diseases especially by their biofilm forming ability.