The biofilm formation of bacteria in different parts of the human body can influence
the success of antibiotic therapy. Essential oils (EOs) and their components are becoming
increasingly popular in point of view of medicinal applications, because of their
antibacterial efficacy. The immortelle EO has been used traditionally as an expectorant;
however, there are no studies summarizing its antibacterial effect against respiratory
tract bacteria. Our aim was to investigate the antibacterial and biofilm inhibitory
activity of immortelle (Helichrysum italicum) EO against respiratory tract pathogens
such as Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa and Streptococcus
pneumoniae. In order to prove the antibacterial effect of the immortelle EO, broth
microdilution and biofilm inhibition tests, and membrane damage assay were investigated.
Scanning electron microscopy was used to identify the structural modifications in
bacterial cells. Our results showed that immortelle EO has antibacterial and anti-biofilm
effects against respiratory tract bacteria used in this study. H. parainfluenzae was
the most sensitive to each treatment, however, P. aeruginosa was the most resistant
bacteria. In conclusion, the studied EO may have a role in the treatment of respiratory
tract infections due to their antibacterial and anti-biofilm activity.
