<i>Cymbopogon citratus</i> L. essential oil as a potential anti-biofilm agent active against antibiotic-resistant bacteria isolated from chronic rhinosinusitis patients

Chronic rhinosinusitis (CRS) is long-term inflammation of the sinuses that can be caused by infection due to antibiotic-resistant bacteria. Biofilm developed by microbes is postulated to cause antibiotic treatment failure. Thus, the anti-biofilm activities of seven Thai herbal essential oils (EOs) against antibiotic-resistant bacteria isolated from CRS patients was investigated. Lemongrass (<i>Cymbopogon citratus</i> L.) EO showed the most effective antibiofilm activity against <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i> and <i>Staphylococcus epidermidis</i> grown as biofilm. GC-MS analysis found that myrcene was the major bioactive compound. Pretreatment with lemongrass EO significantly inhibited biofilm formation of all bacterial strains in more than 50% of cases. Furthermore, confocal microscopy analysis revealed the biofilm-disrupting activity of lemongrass EO against the biofilm matrix of all these bacterial species and also increased <i>P. aeruginosa</i> swarming motility with no toxicity to human cells. These results suggest that lemongrass EO has promising clinical applications as an anti-biofilm agent for CRS patients.