Anti-Virulence Properties of Coridothymus capitatus Essential Oil against Pseudomonas aeruginosa Clinical Isolates from Cystic Fibrosis Patients

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen responsible for nosocomial infections, and is often involved in airway infections of cystic fibrosis (CF) patients. P. aeruginosa virulence is related to its ability to form biofilm, trigger different types of motilities, and produce toxins (for example, bacterial pigments). In this scenario, essential oils (EOs) have gained notoriety for their role in phenotype modulation, including virulence modulation. Among different EOs previously analyzed, herein we investigated the activity of Coridothymus capitatus EO (CCEO) against specific virulence factors produced by P. aeruginosa isolated from CF patients. CCEO showed inhibition of new biofilm formation and reduction in mature biofilm in about half of the tested strains. On selected strains, SEM analysis provided interesting information regarding CCEO action in a pre-adhesion assay. CCEO treatment showed a dramatic modification of the extracellular matrix (ECM) structure. Our results clearly showed a drastic reduction in pyocyanin production (between 84% and 100%) for all tested strains in the presence of CCEO. Finally, CCEO was also able to strongly affect P. aeruginosa swarming and swimming motility for almost all tested strains. In consideration of the novel results obtained on clinical strains isolated from CF patients, CCEO may be a potential candidate to limit P. aeruginosa virulence.

Essential Oils Biofilm Modulation Activity and Machine Learning Analysis on Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

“…In previous reports, it has been demonstrated that EOs can exert either antibacterial [ 15 , 17 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ] or biofilm modulation effects [ 15 , 16 , 17 , 20 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. As a continuation of a previously reported screen for antibacterial and antibiofilm EOs [ 15 , 16 , 17 , 20 , 42 ], herein, 61 previously investigated commercial samples have been evaluated for their abilities to modulate the biofilm formation of six P. aeruginosa clinical strains (22P, 25P, 26P, 27P, 37P, and 39P) in comparison with the reference strains PAO1 and PA14. Except for a few samples, the EOs tested at a concentration of 1.00% v / v showed a wide variability in either positively or negatively modulating bacterial biofilm production.…”

Effect of the antibiotic levofloxacin on the ability of Pseudomonas aeruginosa to form biofilm and produce pyocyanin pigment

“…(Gupte et al, 2021). (Vrenna et al, 2021) indicated that Pyocyanin plays an increasingly prominent role in a variety of serious hospital patient infections and is the main cause of pneumonia and cystic fibrosis, and confirmed that Pyocyanin is more frequent in the pus of clinical isolates than in the environment.…”

Serratiopeptidase Affects the Physiology of Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

“…Assays were also performed on preformed biofilms [ 39 ]. A total of 100 µL of BHI medium containing 1:100 dilution of overnight bacterial culture was used to fill the wells of a sterile 96-well flat-bottomed polystyrene plate and incubated for 24 h at 37 °C under static conditions.…”

“…The determination of pyocyanin production was performed as previously described [ 39 ]. Briefly, single bacterial colonies were inoculated separately in 10 mL of BHI broth with or without 200 U/mL of SPEP and incubated for different times at 37 °C under 180 rpm orbital shaking.…”

“…The swarming assay was performed as previously published by Vrenna and coworkers [ 39 ], with some modifications. Briefly, 200 U/mL SPEP was added to molten swarming agar at a concentration of 200 U/mL.…”