Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance
Antimicrobial resistance is now commonly observed in bacterial isolates from multiple settings, compromising the efficacy of current antimicrobial agents. Therefore, there is an urgent requirement for efficacious novel antimicrobials to be used as therapeutics, prophylactically or as preservatives....
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/11/10/2495 |
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| author | Ryan Sweet Catherine Booth Kathryn Gotts Stephen F. Grove Paul A. Kroon Mark Webber |
| author_facet | Ryan Sweet Catherine Booth Kathryn Gotts Stephen F. Grove Paul A. Kroon Mark Webber |
| author_sort | Ryan Sweet |
| collection | DOAJ |
| description | Antimicrobial resistance is now commonly observed in bacterial isolates from multiple settings, compromising the efficacy of current antimicrobial agents. Therefore, there is an urgent requirement for efficacious novel antimicrobials to be used as therapeutics, prophylactically or as preservatives. One promising source of novel antimicrobial chemicals is phytochemicals, which are secondary metabolites produced by plants for numerous purposes, including antimicrobial defence. In this report, we compare the bioactivity of a range of phytochemical compounds, testing their ability to directly inhibit growth or to potentiate other antimicrobials against <i>Salmonella enterica</i> Typhimurium, <i>Pseudomonas aeruginosa</i>, <i>Listeria monocytogenes</i>, and <i>Staphylococcus aureus</i>. We found that nine compounds displayed consistent bioactivity either as direct antimicrobials or as potentiators. Thymol at 0.5 mg/mL showed the greatest antimicrobial effect and significantly reduced the growth of all species, reducing viable cell populations by 66.8%, 43.2%, 29.5%, and 70.2% against <i>S. enterica</i> Typhimurium, <i>S. aureus</i>, <i>P. aeruginosa</i>, and <i>L. monocytogenes</i>, respectively. Selection of mutants with decreased susceptibility to thymol was possible for three of the pathogens, at a calculated rate of 3.77 × 10<sup>−8</sup>, and characterisation of <i>S. enterica</i> Typhimurium mutants showed a low-level MDR phenotype due to over-expression of the major efflux system AcrAB-TolC. These data show that phytochemicals can have strong antimicrobial activity, but emergence of resistance should be evaluated in any further development. |
| first_indexed | 2024-03-10T21:01:48Z |
| format | Article |
| id | doaj.art-9d4fbbaa2a7b403db5df65f143bac1b1 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T21:01:48Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-9d4fbbaa2a7b403db5df65f143bac1b12023-11-19T17:27:38ZengMDPI AGMicroorganisms2076-26072023-10-011110249510.3390/microorganisms11102495Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of ResistanceRyan Sweet0Catherine Booth1Kathryn Gotts2Stephen F. Grove3Paul A. Kroon4Mark Webber5Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UKQuadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UKQuadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UKMcCain Foods, 1 Tower Lane, Oakbrook Terrace, IL 60181, USAQuadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UKQuadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, UKAntimicrobial resistance is now commonly observed in bacterial isolates from multiple settings, compromising the efficacy of current antimicrobial agents. Therefore, there is an urgent requirement for efficacious novel antimicrobials to be used as therapeutics, prophylactically or as preservatives. One promising source of novel antimicrobial chemicals is phytochemicals, which are secondary metabolites produced by plants for numerous purposes, including antimicrobial defence. In this report, we compare the bioactivity of a range of phytochemical compounds, testing their ability to directly inhibit growth or to potentiate other antimicrobials against <i>Salmonella enterica</i> Typhimurium, <i>Pseudomonas aeruginosa</i>, <i>Listeria monocytogenes</i>, and <i>Staphylococcus aureus</i>. We found that nine compounds displayed consistent bioactivity either as direct antimicrobials or as potentiators. Thymol at 0.5 mg/mL showed the greatest antimicrobial effect and significantly reduced the growth of all species, reducing viable cell populations by 66.8%, 43.2%, 29.5%, and 70.2% against <i>S. enterica</i> Typhimurium, <i>S. aureus</i>, <i>P. aeruginosa</i>, and <i>L. monocytogenes</i>, respectively. Selection of mutants with decreased susceptibility to thymol was possible for three of the pathogens, at a calculated rate of 3.77 × 10<sup>−8</sup>, and characterisation of <i>S. enterica</i> Typhimurium mutants showed a low-level MDR phenotype due to over-expression of the major efflux system AcrAB-TolC. These data show that phytochemicals can have strong antimicrobial activity, but emergence of resistance should be evaluated in any further development.https://www.mdpi.com/2076-2607/11/10/2495antimicrobial resistanceAMRphenolicsflavonoidsnatural products |
| spellingShingle | Ryan Sweet Catherine Booth Kathryn Gotts Stephen F. Grove Paul A. Kroon Mark Webber Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance Microorganisms antimicrobial resistance AMR phenolics flavonoids natural products |
| title | Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance |
| title_full | Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance |
| title_fullStr | Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance |
| title_full_unstemmed | Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance |
| title_short | Comparison of Antibacterial Activity of Phytochemicals against Common Foodborne Pathogens and Potential for Selection of Resistance |
| title_sort | comparison of antibacterial activity of phytochemicals against common foodborne pathogens and potential for selection of resistance |
| topic | antimicrobial resistance AMR phenolics flavonoids natural products |
| url | https://www.mdpi.com/2076-2607/11/10/2495 |
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