The Inhibition Effects of Eugenol and Pulegone on Stenotrophomonas maltophilia: an Opportunistic Pathogen

TLDR: According to the biological activity results, it can be concluded that these natural agents may be potentially used for veterinary sciences, food industry or pharmaceutical applications that aim to manage S. maltophilia biofilm.

Abstract: Aerobic, non-fermentative and Gram-negative Stenotrophomonas maltophilia is a multidrug-resistant bacilli that is known to be pathogen for human and animals. S. maltophilia has been isolated from different animal species and also found in a variety of environments including soil, water, and plants. S. maltophilia , which has the ability to form biofilms on surfaces that cause environmental problems, is resistant to many antibiotic classes such as cephalosporins, carbapenems, and aminoglycosides.  Here in this study, its aimed to determine the inhibition activities of natural phenolic compounds eugenol and pulegone against S. maltophilia MU69. Antibacterial activities of eugenol and pulegone were initially determined by disc diffusion method. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were also determined by tube dilution assay. Antibiofilm activities of the compounds were investigated by crystal violet staining and also monitorized using Scanning Electron Microscopy (SEM). Zone of inhibition measurements were found to be 39 mm and 28 mm for eugenol and pulegone, respectively. MIC and MBC values were found to be 3.12 mg/mL for eugenol while these were 2.5 mg/mL and 5 mg/mL for pulegone, respectively. The highest antibiofilm activity was found to be 56.30±0.45% for MIC of eugenol. To our knowledge, this is the first report of the antibacterial and antibiofilm activity of eugenol and pulegone against S. maltophilia . According to the biological activity results, it can be concluded that these natural agents may be potentially used for veterinary sciences, food industry or pharmaceutical applications that aim to manage S. maltophilia biofilm.