Abstract
The antibiotic resistance of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased drastically in recent years. In our study, we determined the principle mechanisms of action for the food-grade additive carvacrol against ESBL E. coli isolated from the blood of patients with a urinary tract infection. Carvacrol, which has a minimum inhibitory concentration of 150 μg/ml and a minimum bactericidal concentration of 300 μg/ml, reduced E. coli cell counts in a time-dependent manner. After treatment with carvacrol, the E. coli killing time was found to be 120 min. Fluorescent staining confirmed an increase in bacterial cell death, greater membrane depolarization, and an elevated oxidative burst in carvacrol-treated E. coli. Carvacrol also induced the release of cellular DNA, proteins, and potassium ions from bacterial cells and reduced both the number of E. coli in invasion assays against macrophages and the levels of the inflammatory proteins TNF-α and COX-2. In addition, carvacrol was found to inhibit β-lactamase enzyme activity (in vitro), which was supported by in silico results. Moreover, carvacrol inhibited motility, and protected against bacterial invasion. Overall, the findings suggest that carvacrol has significant antimicrobial potential against ESBL E. coli.
Original language | English (US) |
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Article number | 104046 |
Journal | Microbial Pathogenesis |
Volume | 142 |
Early online date | Feb 12 2020 |
DOIs | |
State | Published - May 2020 |
Bibliographical note
Funding Information:This work was supported by the Basic Science Research Program through the National Research Foundation of Korea ( NRF-2014R1A5A1009799 and NRF-2019R1A2B5B01070543 ) funded by the Ministry of Science, ICT and Future Planning (MSIP) , Republic of Korea.
Publisher Copyright:
© 2020 Elsevier Ltd
Keywords
- Carvacrol
- Escherichia coli
- Extended-spectrum β-lactamase
- Reactive oxygen species
- Urinary tract infection
PubMed: MeSH publication types
- Journal Article