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Essential Oils from Southern Italian Aromatic Plants Synergize with Antibiotics against Escherichia coli , Pseudomonas aeruginosa and Enterococcus faecalis Cell Growth and Biofilm Formation.

Authors :
Sena, Giada
De Rose, Elisabetta
Crudo, Michele
Filippelli, Gianfranco
Passarino, Giuseppe
Bellizzi, Dina
D'Aquila, Patrizia
Source :
Antibiotics (2079-6382); Jul2024, Vol. 13 Issue 7, p605, 18p
Publication Year :
2024

Abstract

The spread of antibiotic-resistant pathogens has prompted the development of novel approaches to identify molecules that synergize with antibiotics to enhance their efficacy. This study aimed to investigate the effects of ten Essential Oils (EOs) on the activity of nine antibiotics in influencing growth and biofilm formation in Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis. The effects of the EOs alone and in combination with antibiotics on both bacterial growth and biofilm formation were analyzed by measuring the MIC values through the broth microdilution method and the crystal violet assay, respectively. All EOs inhibited the growth of E. coli (1.25 ≤ MIC ≤ 5 mg/mL) while the growth of P. aeruginosa and E. faecalis was only affected by EOs from Origanum vulgare, (MIC = 5 mg/mL) and O. vulgare (MIC = 1.25 mg/mL) and Salvia rosmarinus (MIC = 5 mg/mL), respectively. In E. coli, most EOs induced a four- to sixteen-fold reduction in the MIC values of ampicillin, ciprofloxacin, ceftriaxone, gentamicin, and streptomycin, while in E. faecalis such a reduction is observed in combinations of ciprofloxacin with C. nepeta, C. bergamia, C. limon, C. reticulata, and F. vulgare, of gentamicin with O. vulgare, and of tetracycline with C. limon and O. vulgare. A smaller effect was observed in P. aeruginosa, in which only C. bergamia reduced the concentration of tetracycline four-fold. EO-antibiotic combinations also inhibit the biofilm formation. More precisely, all EOs with ciprofloxacin in E. coli, tetracycline in P. aeruginosa, and gentamicin in E. faecalis showed the highest percentage of inhibition. Combinations induce up- and down-methylation of cytosines and adenines compared to EO or antibiotics alone. The study provides evidence about the role of EOs in enhancing the action of antibiotics by influencing key processes involved in resistance mechanisms such as biofilm formation and epigenetic changes. Synergistic interactions should be effectively considered in dealing with pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20796382
Volume :
13
Issue :
7
Database :
Complementary Index
Journal :
Antibiotics (2079-6382)
Publication Type :
Academic Journal
Accession number :
178699599
Full Text :
https://doi.org/10.3390/antibiotics13070605