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Se J, Xie Y, Ma Q, Zhu L, Fu Y, Xu X, Shen C, Nannipieri P. Drying-wetting cycle enhances stress resistance of Escherichia coli O157:H7 in a model soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 350:123988. [PMID: 38648967 DOI: 10.1016/j.envpol.2024.123988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/13/2024] [Accepted: 04/13/2024] [Indexed: 04/25/2024]
Abstract
Outbreaks of Escherichia coli (E. coli) O157:H7 in farms are often triggered by heavy rains and flooding. Most cells die with the decreasing of soil moisture, while few cells enter a dormant state and then resuscitate after rewetting. The resistance of dormant cells to stress has been extensively studied, whereas the molecular mechanisms of the cross-resistance development of the resuscitated cells are poorly known. We performed a comparative proteomic analysis on O157:H7 before and after undergoing soil dry-wet alternation. A differential expression of 820 proteins was identified in resuscitated cells compared to exponential-phase cells, as determined by proteomics analysis. The GO and KEGG pathway enrichment analyses revealed that up-regulated proteins were associated with oxidative phosphorylation, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), aminoacyl-tRNA biosynthesis, ribosome activity, and transmembrane transporters, indicating increased energy production and protein synthesis in resuscitated O157:H7. Moreover, proteins related to acid, osmotic, heat, oxidative, antibiotic stress and horizontal gene transfer efficiency were up-regulated, suggesting a potential improvement in stress resistance. Subsequent validation experiments demonstrated that the survival rates of the resuscitated cells were 476.54 and 7786.34 times higher than the exponential-phase cells, with pH levels of 1.5 and 2.5, respectively. Similarly, resuscitated cells showed higher survival rates under osmotic stress, with 7.5%, 15%, and 30% NaCl resulting in survival rates that were 460.58, 1974.55, and 3475.31 times higher. Resuscitated cells also exhibited increased resistance to heat stress, with survival rates 69.64 and 139.72 times higher at 55 °C and 90 °C, respectively. Furthermore, the horizontal gene transfer (HGT) efficiency of resuscitated cells was significantly higher (153.12-fold) compared to exponential phase cells. This study provides new insights into bacteria behavior under changing soil moisture and this may explain O157:H7 outbreaks following rainfall and flooding, as the dry-wet cycle promotes stress cross-resistance development.
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Affiliation(s)
- Jing Se
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China
| | - Yinan Xie
- Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Qingxu Ma
- Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Lin Zhu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China
| | - Yulong Fu
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China
| | - Xin Xu
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China
| | - Chaofeng Shen
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China.
| | - Paolo Nannipieri
- Emeritus Professor, University of Firenze, Firenze, 50144, Italy
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Merino N, Berdejo D, Pagán E, Girard C, Kerros S, Spinozzi E, Pagán R, García-Gonzalo D. Phenotypic and Genotypic Comparison of Antimicrobial-Resistant Variants of Escherichia coli and Salmonella Typhimurium Isolated from Evolution Assays with Antibiotics or Commercial Products Based on Essential Oils. Pharmaceuticals (Basel) 2023; 16:1443. [PMID: 37895914 PMCID: PMC10610042 DOI: 10.3390/ph16101443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/06/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
On account of the widespread development and propagation of antimicrobial-resistant (AMR) bacteria, essential oils (EOs) have emerged as potential alternatives to antibiotics. However, as already observed for antibiotics, recent studies have raised concerns regarding the potential emergence of resistant variants (RVs) to EOs. In this study, we assessed the emergence of RVs in Escherichia coli and Salmonella enterica Typhimurium after evolution assays under extended exposure to subinhibitory doses of two commercial EOs (AEN and COLIFIT) as well as to two antibiotics (amoxicillin and colistin). Phenotypic characterization of RVs from evolution assays with commercial EOs yielded no relevant increases in the minimum inhibitory concentration (MIC) of E. coli and did not even modify MIC values in S. Typhimurium. Conversely, RVs of E. coli and S. Typhimurium isolated from evolution assays with antibiotics showed increased resistance. Genotypic analysis demonstrated that resistance to commercial EOs was associated with enhanced protection against oxidative stress and redirection of cell energy toward efflux activity, while resistance to antibiotics was primarily linked to modifications in the cell binding sites of antibiotics. These findings suggest that AEN and COLIFIT could serve as safe alternatives to antibiotics in combating the emergence and dissemination of antimicrobial resistance within the agrifood system.
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Affiliation(s)
- Natalia Merino
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain
| | - Daniel Berdejo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain
| | - Elisa Pagán
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain
| | | | | | - Eleonora Spinozzi
- Chemistry Interdiscplinary Project (ChIP), School of Pharmacy, University of Camerino, 62032 Camerino, Italy
| | - Rafael Pagán
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain
| | - Diego García-Gonzalo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain
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3
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Li A, Fan J, Jia Y, Tang X, Chen J, Shen C. Phenotype and metabolism alterations in PCB-degrading Rhodococcus biphenylivorans TG9 T under acid stress. J Environ Sci (China) 2023; 127:441-452. [PMID: 36522076 DOI: 10.1016/j.jes.2022.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 06/17/2023]
Abstract
Environmental acidification impairs microorganism diversity and their functions on substance transformation. Rhodococcus is a ubiquitously distributed genus for contaminant detoxification in the environment, and it can also adapt a certain range of pH. This work interpreted the acid responses from both phenotype and metabolism in strain Rhodococcus biphenylivorans TG9T (TG9) induced at pH 3. The phenotype alterations were described with the number of culturable and viable cells, intracellular ATP concentrations, cell shape and entocyte, degradation efficiency of polychlorinated biphenyl (PCB) 31 and biphenyl. The number of culturable cells maintained rather stable within the first 10 days, even though the other phenotypes had noticeable alterations, indicating that TG9 possesses certain capacities to survive under acid stress. The metabolism responses were interpreted based on transcription analyses with four treatments including log phase (LP), acid-induced (PER), early recovery after removing acid (RE) and later recovery (REL). With the overview on the expression regulations among the 4 treatments, the RE sample presented more upregulated and less downregulated genes, suggesting that its metabolism was somehow more active after recovering from acid stress. In addition, the response mechanism was interpreted on 10 individual metabolism pathways mainly covering protein modification, antioxidation, antipermeability, H+ consumption, neutralization and extrusion. Furthermore, the transcription variations were verified with RT-qPCR on 8 genes with 24-hr, 48-hr and 72-hr acid treatment. Taken together, TG9 possesses comprehensive metabolism strategies defending against acid stress. Consequently, a model was built to provide an integrate insight to understand the acid resistance/tolerance metabolisms in microorganisms.
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Affiliation(s)
- Aili Li
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiahui Fan
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yangyang Jia
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xianjin Tang
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jingwen Chen
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chaofeng Shen
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
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Carvalho F, Coimbra AT, Silva L, Duarte AP, Ferreira S. Melissa officinalis essential oil as an antimicrobial agent against Listeria monocytogenes in watermelon juice. Food Microbiol 2023; 109:104105. [DOI: 10.1016/j.fm.2022.104105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 10/15/2022]
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5
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Hakeem MJ, Feng J, Ma L, Ma L, Lu X. Whole transcriptome sequencing analysis of synergistic combinations of plant-based antimicrobials and zinc oxide nanoparticles against Campylobacter jejuni. Microbiol Res 2023; 266:127246. [DOI: 10.1016/j.micres.2022.127246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/25/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022]
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6
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Transcriptomic and phenotypic changes of Cronobacter sakazakii ATCC 29544 grown under desiccation stress. Lebensm Wiss Technol 2023. [DOI: 10.1016/j.lwt.2022.114279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Correlation between Perturbation of Redox Homeostasis and Antibiofilm Capacity of Phytochemicals at Non-Lethal Concentrations. Antioxidants (Basel) 2022; 11:antiox11122451. [PMID: 36552659 PMCID: PMC9774353 DOI: 10.3390/antiox11122451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022] Open
Abstract
Biofilms are the multicellular lifestyle of microorganisms and are present on potentially every type of biotic or abiotic surface. Detrimental biofilms are generally targeted with antimicrobial compounds. Phytochemicals at sub-lethal concentrations seem to be an exciting alternative strategy to control biofilms, as they are less likely to impose selective pressure leading to resistance. This overview gathers the literature on individual phytocompounds rather than on extracts of which the use is difficult to reproduce. To the best of our knowledge, this is the first review to target only individual phytochemicals below inhibitory concentrations against biofilm formation. We explored whether there is an overall mechanism that can explain the effects of individual phytochemicals at sub-lethal concentrations. Interestingly, in all experiments reported here in which oxidative stress was investigated, a modest increase in intracellular reactive oxygen species was reported in treated cells compared to untreated specimens. At sub-lethal concentrations, polyphenolic substances likely act as pro-oxidants by disturbing the healthy redox cycle and causing an accumulation of reactive oxygen species.
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8
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Chen L, Zhao X, Li R, Yang H. Integrated metabolomics and transcriptomics reveal the adaptive responses of Salmonella enterica serovar Typhimurium to thyme and cinnamon oils. Food Res Int 2022; 157:111241. [DOI: 10.1016/j.foodres.2022.111241] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 01/22/2023]
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9
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Scandorieiro S, Rodrigues BCD, Nishio EK, Panagio LA, de Oliveira AG, Durán N, Nakazato G, Kobayashi RKT. Biogenic Silver Nanoparticles Strategically Combined With Origanum vulgare Derivatives: Antibacterial Mechanism of Action and Effect on Multidrug-Resistant Strains. Front Microbiol 2022; 13:842600. [PMID: 35602016 PMCID: PMC9121793 DOI: 10.3389/fmicb.2022.842600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/11/2022] [Indexed: 12/27/2022] Open
Abstract
Multidrug-resistant bacteria have become a public health problem worldwide, reducing treatment options against several pathogens. If we do not act against this problem, it is estimated that by 2050 superbugs will kill more people than the current COVID-19 pandemic. Among solutions to combat antibacterial resistance, there is increasing demand for new antimicrobials. The antibacterial activity of binary combinations containing bioAgNP (biogenically synthesized silver nanoparticles using Fusarium oxysporum), oregano essential oil (OEO), carvacrol (Car), and thymol (Thy) was evaluated: OEO plus bioAgNP, Car plus bioAgNP, Thy plus bioAgNP, and Car plus Thy. This study shows that the mechanism of action of Thy, bioAgNP, and Thy plus bioAgNP involves damaging the membrane and cell wall (surface blebbing and disruption seen with an electron microscope), causing cytoplasmic molecule leakage (ATP, DNA, RNA, and total proteins) and oxidative stress by enhancing intracellular reactive oxygen species and lipid peroxidation; a similar mechanism happens for OEO and Car, except for oxidative stress. The combination containing bioAgNP and oregano derivatives, especially thymol, shows strategic antibacterial mechanism; thymol disturbs the selective permeability of the cell membrane and consequently facilitates access of the nanoparticles to bacterial cytoplasm. BioAgNP-treated Escherichia coli developed resistance to nanosilver after 12 days of daily exposition. The combination of Thy and bioAgNP prevented the emergence of resistance to both antimicrobials; therefore, mixture of antimicrobials is a strategy to extend their life. For antimicrobials alone, minimal bactericidal concentration ranges were 0.3-2.38 mg/ml (OEO), 0.31-1.22 mg/ml (Car), 0.25-1 mg/ml (Thy), and 15.75-31.5 μg/ml (bioAgNP). The time-kill assays showed that the oregano derivatives acted very fast (at least 10 s), while the bioAgNP took at least 30 min to kill Gram-negative bacteria and 7 h to kill methicillin-resistant Staphylococcus aureus (MRSA). All the combinations resulted in additive antibacterial effect, reducing significantly minimal inhibitory concentration and acting faster than the bioAgNP alone; they also showed no cytotoxicity. This study describes for the first time the effect of Car and Thy combined with bioAgNP (produced with F. oxysporum components) against bacteria for which efficient antimicrobials are urgently needed, such as carbapenem-resistant strains (E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) and MRSA.
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Affiliation(s)
- Sara Scandorieiro
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Bianca C. D. Rodrigues
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Erick K. Nishio
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Luciano A. Panagio
- Laboratory of Medical Mycology and Oral Mycology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Admilton G. de Oliveira
- Laboratory of Microbial Biotechnology, Department of Microbiology – Laboratory of Electron Microscopy and Microanalysis, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Nelson Durán
- Institute of Biology, Universidade Estadual de Campinas, Campinas, Brazil
| | - Gerson Nakazato
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
| | - Renata K. T. Kobayashi
- Laboratory of Basic and Applied Bacteriology, Department of Microbiology, Center of Biological Sciences, Universidade Estadual de Londrina, Londrina, Brazil
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10
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Heat shock in Cronobacter sakazakii induces direct protection and cross-protection against simulated gastric fluid stress. Food Microbiol 2022; 103:103948. [DOI: 10.1016/j.fm.2021.103948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 11/21/2022]
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11
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Al-Mnaser A, Dakheel M, Alkandari F, Woodward M. Polyphenolic phytochemicals as natural feed additives to control bacterial pathogens in the chicken gut. Arch Microbiol 2022; 204:253. [PMID: 35412092 PMCID: PMC9001821 DOI: 10.1007/s00203-022-02862-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 01/21/2023]
Abstract
Poultry provides an important protein source consumed globally by human population, and simultaneously, acts as a substantial reservoir of antibiotic resistant bacterial species such as Escherichia coli, Salmonella, Campylobacter, Clostridium perfringens. These bacterial species can include commensal strains with beneficial roles on poultry health and productivity, and pathogenic strains not only to poultry but zoonotically to man. This review paper evaluates the role of phytochemicals as possible alternatives to antibiotics and natural anti-bacterial agents to control antibiotic resistance in poultry. The focus of this paper is on the polyphenolic phytochemicals as they constitute the major group; carvacrol oil (the active ingredient of oregano), thymol oil (the main ingredient of oregano), oregano oil, and tannins oil as feed additives and their mechanism of actions that might enhance avian gut health by controlling antibiotic-resistant bacterial strains spread in poultry.
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Affiliation(s)
- Afnan Al-Mnaser
- Department of Food and Nutritional Sciences, School of Chemistry, Food and Pharmacy, University of Reading, Reading, RG6 6DZ, UK.
- Dasman Diabetes Institute, Dasman, Sharq, Kuwait.
| | - Mohammed Dakheel
- Department of Veterinary Public Health, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq
| | - Fatemah Alkandari
- Department of Plant Protection, Public Authority of Agriculture Affairs and Fish Resources, Al-Rabia, Kuwait
| | - Martin Woodward
- Department of Food and Nutritional Sciences, School of Chemistry, Food and Pharmacy, University of Reading, Reading, RG6 6DZ, UK
- Folium Science, Unit DX, Bristol, BS2 0XJ, UK
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12
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Li Q, Yu S, Han J, Wu J, You L, Shi X, Wang S. Synergistic antibacterial activity and mechanism of action of nisin/carvacrol combination against Staphylococcus aureus and their application in the infecting pasteurized milk. Food Chem 2022; 380:132009. [PMID: 35077986 DOI: 10.1016/j.foodchem.2021.132009] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/14/2021] [Accepted: 12/14/2021] [Indexed: 11/04/2022]
Abstract
Synergistic antibacterial effect is a promising way to overcome the challenge of microbial contamination in food. In this study, we detected the synergistic interactions of nisin and carvacrol. The MIC of nisin and carvacrol against S. aureus were 60 and 125 μg/mL, respectively. The FICI and FBCI were 0.28125 and 0.09375, which suggested that the nisin/carvacrol combination presented synergistic antibacterial effect against S. aureus. The antibacterial activity of nisin/carvacrol combination was much higher than their individuals and the dose of antibacterials was obviously reduced. The combination could completely kill S. aureus within 8 h, accelerate the destruction of cell membrane, and inhibit formation of biofilm. Under the intervention of nisin, more CAR could enter cell to hunt intracellular targets, leading to an increase in intracellular antibacterial level. Besides, in the storage of pasteurized milk, the combinational treatment successfully inhibited microbial reproduction at 25 °C and 4 °C. Thus, the combination of nisin and carvacrol was a potential synergistic strategy for food preservation.
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Affiliation(s)
- Qingxiang Li
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China
| | - Shuna Yu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China
| | - Jinzhi Han
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China
| | - Jiulin Wu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China.
| | - Lijun You
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China
| | - Xiaodan Shi
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China
| | - Shaoyun Wang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, PR China.
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Shi D, Shi H. The synergistic antibacterial effect and inhibition of biofilm formation of nisin in combination with terpenes against Listeria monocytogenes. Lett Appl Microbiol 2021; 75:632-642. [PMID: 34953143 DOI: 10.1111/lam.13636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/16/2021] [Accepted: 12/15/2021] [Indexed: 11/29/2022]
Abstract
This study was to investigate the synergistic antibacterial effect and inhibition of biofilm formation of nisin in combination with terpenes (carvacrol, cinnamaldehyde, citral, and thymol) against Listeria monocytogenes. The bactericidal ranking of terpenes combined with nisin was carvacrol > cinnamaldehyde, citral > thymol. The minimum inhibitory concentration assay (MIC) of nisin and carvacrol when used together were determined to be 0.1563 mg/ml + 0.0195 mg/ml (nisin at MIC/2 + carvacrol at MIC/16). The addition of nisin at MIC/2 + carvacrol at MIC/2 caused more decrease in membrane potential than carvacrol or nisin at MIC individually. The decrease rates of hlyA and plcA gene expressions caused by nisin at MIC/2 + carvacrol at MIC/2 were significantly higher than those caused by carvacrol or nisin at MIC individually (P < 0.05). Nisin combined with carvacrol showed the highest inhibition activity to formation of L. monocytogenes biofilm on stainless steel and lettuce. The inhibition effect of nisin at MIC/2 + carvacrol at MIC/16 was significantly higher than that of nisin at MIC/2 and carvacrol at MIC/16 (P < 0.05).
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Affiliation(s)
- Dongling Shi
- College of Food Science, Southwest University, Chongqing, China, 400715
| | - Hui Shi
- College of Food Science, Southwest University, Chongqing, China, 400715
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14
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New insights into the formation and recovery of sublethally injured Escherichia coli O157:H7 induced by lactic acid. Food Microbiol 2021; 102:103918. [PMID: 34809944 DOI: 10.1016/j.fm.2021.103918] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 08/19/2021] [Accepted: 09/26/2021] [Indexed: 11/21/2022]
Abstract
Escherichia coli O157:H7 can be injured by the action of lactic acid (LA) and injured cells can be recovered under suitable condition. In this study, RNA sequencing analysis revealed the overall genes change of sublethally injured (4 mM LA, 60 min; SI) and initial recovered (minA, 20 min; R) cells. Compared with untreated samples, 53 up-regulated and 98 down-regulated differentially expressed genes (DEGs; Padj < 0.05, change fold ≥2) were found in SI. Meanwhile, Genes related to carbohydrate transport and metabolic were up-regulated and the addition of carbohydrate increased cells resistance to LA. Genes involved in osmotic stress response and cell membrane integrity were down-regulated and E. coli O157:H7 cells were sensitive to osmotic stress during sublethal injury. Genes related to iron stress response and cation transport were changed and cation may affect sublethal injury formation by influencing production of ROS and cellular processes. In R, 1370 up-regulated and 1110 down-regulated DEGs were subdivided into various GO terms and membrane, biological adhesion, cell projection, oxidation-reduction process and catalytic activity, etc., showed significant enrichment (corrected P < 0.05). Particularly, genes related to fimbrial, flagellum and type III secretion system were up-regulated, which may improve infection ability and virulence property during recovery of injured cells. These findings provide novel insights into formation and recovery of sublethally injured E. coli O157:H7 induced by LA.
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15
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Sun L, Rogiers G, Michiels CW. The Natural Antimicrobial trans-Cinnamaldehyde Interferes with UDP-N-Acetylglucosamine Biosynthesis and Cell Wall Homeostasis in Listeria monocytogenes. Foods 2021; 10:foods10071666. [PMID: 34359536 PMCID: PMC8307235 DOI: 10.3390/foods10071666] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/12/2021] [Accepted: 07/16/2021] [Indexed: 01/07/2023] Open
Abstract
Trans-cinnamaldehyde (t-CIN), an antimicrobial compound from cinnamon essential oil, is of interest because it inhibits various foodborne pathogens. In the present work, we investigated the antimicrobial mechanisms of t-CIN in Listeria monocytogenes using a previously isolated yvcK::Himar1 transposon mutant which shows hypersensitivity to t-CIN. Time-lapse microscopy revealed that t-CIN induces a bulging cell shape followed by lysis in the mutant. Complementation with wild-type yvcK gene completely restored the tolerance of yvcK::Himar1 strain to t-CIN and the cell morphology. Suppressor mutants which partially reversed the t-CIN sensitivity of the yvcK::Himar1 mutant were isolated from evolutionary experiments. Three out of five suppression mutations were in the glmU-prs operon and in nagR, which are linked to the biosynthesis of the peptidoglycan precursor uridine-diphosphate-N-acetylglucosamine (UDP-GlcNAc). GlmU catalyzes the last two steps of UDP-GlcNAc biosynthesis and NagR represses the uptake and utilization of N-acetylglucosamine. Feeding N-acetylglucosamine or increasing the production of UDP-GlcNAc synthetic enzymes fully or partially restored the t-CIN tolerance of the yvcK mutant. Together, these results suggest that YvcK plays a pivotal role in diverting substrates to UDP-GlcNAc biosynthesis in L. monocytogenes and that t-CIN interferes with this pathway, leading to a peptidoglycan synthesis defect.
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16
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Chang Y, Bai J, Yu H, Chang PS, Nitin N. Synergistic Inactivation of Bacteria Using a Combination of Erythorbyl Laurate and UV Type-A Light Treatment. Front Microbiol 2021; 12:682900. [PMID: 34335506 PMCID: PMC8322444 DOI: 10.3389/fmicb.2021.682900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/25/2021] [Indexed: 11/13/2022] Open
Abstract
This study evaluated the synergistic antimicrobial activity of erythorbyl laurate (EL) and UV type-A (UVA). To investigate the mode of synergism, changes in gene expression and bacterial inactivation activity were examined. Individual treatments with EL (10 mM) or UVA caused a 1.9- or 0.5-log CFU/ml reduction respectively, whereas EL/UVA co-treatment resulted in a 5.5-log CFU/ml reduction in Escherichia coli viable cell numbers. Similarly, treatment with either EL (2 mM) or UVA for 30 min resulted in a 2.8- or 0.1-log CFU/ml reduction in Listeria innocua, respectively, whereas combined treatment with both EL and UVA resulted in a 5.4-log CFU/ml reduction. Measurements of gene expression levels showed that EL and UVA treatment synergistically altered the gene expression of genes related to bacterial membrane synthesis/stress response. However, addition of 10–50-fold excess concentration of exogenous antioxidant compared to EL reduced the synergistic effect of EL and UVA by approximately 1 log. In summary, the results illustrate that synergistic combination of EL and UVA enhanced membrane damage independent of the oxidative stress damage induced by UVA and thus illustrate a novel photo-activated synergistic antimicrobial approach for the inactivation of both the Gram-positive and Gram-negative bacteria. Overall, this study illustrates mechanistic evaluation of a novel photochemical approach for food and environmental applications.
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Affiliation(s)
- Yoonjee Chang
- Department of Food and Nutrition, Kookmin University, Seoul, South Korea.,Department of Food Science and Technology, University of California, Davis, Davis, CA, United States
| | - Jaewoo Bai
- Department of Food Science and Technology, University of California, Davis, Davis, CA, United States.,Division of Applied Food System, Major in Food Science & Technology, Seoul Women's University, Seoul, South Korea
| | - Hyunjong Yu
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Pahn-Shick Chang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea.,Research Institute of Agriculture and Life Science, Seoul National University, Seoul, South Korea
| | - Nitin Nitin
- Department of Food Science and Technology, University of California, Davis, Davis, CA, United States.,Department of Biological and Agricultural Engineering, University of California, Davis, Davis, CA, United States
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17
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Natural Anti-Microbials for Enhanced Microbial Safety and Shelf-Life of Processed Packaged Meat. Foods 2021; 10:foods10071598. [PMID: 34359468 PMCID: PMC8305275 DOI: 10.3390/foods10071598] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/30/2021] [Accepted: 07/06/2021] [Indexed: 12/14/2022] Open
Abstract
Microbial food contamination is a major concern for consumers and food industries. Consumers desire nutritious, safe and “clean label” products, free of synthetic preservatives and food industries and food scientists try to meet their demands by finding natural effective alternatives for food preservation. One of the alternatives to synthetic preservatives is the use of natural anti-microbial agents in the food products and/or in the packaging materials. Meat and processed meat products are characteristic examples of products that are highly perishable; hence natural anti-microbials can be used for extending their shelf-life and enhancing their safety. Despite several examples of the successful application of natural anti-microbial agents in meat products reported in research studies, their commercial use remains limited. This review objective is to present an extensive overview of recent research in the field of natural anti-microbials, covering essential oils, plant extracts, flavonoids, animal-derived compounds, organic acids, bacteriocins and nanoparticles. The anti-microbial mode of action of the agents, in situ studies involving meat products, regulations and, limitations for usage and future perspectives are described. The review concludes that naturally derived anti-microbials can potentially support the meat industry to provide “clean label”, nutritious and safe meat products for consumers.
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18
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Giacometti F, Shirzad-Aski H, Ferreira S. Antimicrobials and Food-Related Stresses as Selective Factors for Antibiotic Resistance along the Farm to Fork Continuum. Antibiotics (Basel) 2021; 10:671. [PMID: 34199740 PMCID: PMC8230312 DOI: 10.3390/antibiotics10060671] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/29/2021] [Accepted: 06/01/2021] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global problem and there has been growing concern associated with its widespread along the animal-human-environment interface. The farm-to-fork continuum was highlighted as a possible reservoir of AMR, and a hotspot for the emergence and spread of AMR. However, the extent of the role of non-antibiotic antimicrobials and other food-related stresses as selective factors is still in need of clarification. This review addresses the use of non-antibiotic stressors, such as antimicrobials, food-processing treatments, or even novel approaches to ensure food safety, as potential drivers for resistance to clinically relevant antibiotics. The co-selection and cross-adaptation events are covered, which may induce a decreased susceptibility of foodborne bacteria to antibiotics. Although the available studies address the complexity involved in these phenomena, further studies are needed to help better understand the real risk of using food-chain-related stressors, and possibly to allow the establishment of early warnings of potential resistance mechanisms.
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Affiliation(s)
- Federica Giacometti
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, 40064 Bologna, Italy;
| | - Hesamaddin Shirzad-Aski
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan 49178-67439, Iran;
| | - Susana Ferreira
- CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, 6200-506 Covilhã, Portugal
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19
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Du GF, Yin XF, Yang DH, He QY, Sun X. Proteomic Investigation of the Antibacterial Mechanism of trans-Cinnamaldehyde against Escherichia coli. J Proteome Res 2021; 20:2319-2328. [PMID: 33749271 DOI: 10.1021/acs.jproteome.0c00847] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Trans-Cinnamaldehyde (TC) is a widely used food additive, known for its sterilization, disinfection, and antiseptic properties. However, its antibacterial mechanism is not completely understood. In this study, quantitative proteomics was performed to investigate differentially expressed proteins (DEPs) in Escherichia coli in response to TC treatment. Bioinformatics analysis suggested aldehyde toxicity, acid stress, oxidative stress, interference of carbohydrate metabolism, energy metabolism, and protein translation as the bactericidal mechanism. E. coli BW25113ΔyqhD, ΔgldA, ΔbetB, ΔtktB, ΔgadA, ΔgadB, ΔgadC, and Δrmf were used to investigate the functions of DEPs through biochemical methods. The present study revealed that TC exerts its antibacterial effects by inducing the toxicity of its aldehyde group producing acid stress. These findings will contribute to the application of TC in the antibacterial field.
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Affiliation(s)
- Gao-Fei Du
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China.,Medical Technology School, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xing-Feng Yin
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Dong-Hong Yang
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Qing-Yu He
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Xuesong Sun
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
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20
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Berdejo D, Merino N, Pagán E, García-Gonzalo D, Pagán R. Genetic Variants and Phenotypic Characteristics of Salmonella Typhimurium-Resistant Mutants after Exposure to Carvacrol. Microorganisms 2020; 8:microorganisms8060937. [PMID: 32580471 PMCID: PMC7356045 DOI: 10.3390/microorganisms8060937] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 12/12/2022] Open
Abstract
The emergence of antimicrobial resistance has raised questions about the safety of essential oils and their individual constituents as food preservatives and as disinfection agents. Further research is required to understand how and under what conditions stable genotypic resistance might occur in food pathogens. Evolution experiments on Salmonella Typhimurium cyclically exposed to sublethal and lethal doses of carvacrol permitted the isolation of SeSCar and SeLCar strains, respectively. Both evolved strains showed a significant increase in carvacrol resistance, assessed by minimum inhibitory and bactericidal concentrations, the study of growth kinetics in the presence of carvacrol, and the evaluation of survival under lethal conditions. Moreover, antibiotic susceptibility tests revealed a development of SeLCar resistance to a wide range of antibiotics. Whole genome sequencing allowed the identification of single nucleotide variations in transcriptional regulators of oxidative stress-response: yfhP in SeSCar and soxR in SeLCar, which could be responsible for the increased resistance by improving the response to carvacrol and preventing its accumulation inside the cell. This study demonstrates the emergence of S. Typhimurium-resistant mutants against carvacrol, which might pose a risk to food safety and should therefore be considered in the design of food preservation strategies, or of cleaning and disinfection treatments.
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21
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Al-Kandari F, Al-Temaimi R, van Vliet AHM, Woodward MJ. Thymol tolerance in Escherichia coli induces morphological, metabolic and genetic changes. BMC Microbiol 2019; 19:294. [PMID: 31842755 PMCID: PMC6915861 DOI: 10.1186/s12866-019-1663-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 11/26/2019] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Thymol is a phenolic compound used for its wide spectrum antimicrobial activity. There is a limited understanding of the antimicrobial mechanisms underlying thymol activity. To investigate this, E. coli strain JM109 was exposed to thymol at sub-lethal concentrations and after 16 rounds of exposure, isolates with a 2-fold increased minimal inhibitory concentration (MIC) were recovered (JM109-Thyr). The phenotype was stable after multiple sub-cultures without thymol. RESULTS Cell morphology studies by scanning electron microscopy (SEM) suggest that thymol renders bacterial cell membranes permeable and disrupts cellular integrity. 1H Nuclear magnetic resonance (NMR) data showed an increase in lactate and the lactic acid family amino acids in the wild type and JM109-Thyr in the presence of thymol, indicating a shift from aerobic respiration to fermentation. Sequencing of JM109-Thyr defined multiple mutations including a stop mutation in the acrR gene resulting in a truncation of the repressor of the AcrAB efflux pump. AcrAB is a multiprotein complex traversing the cytoplasmic and outer membrane, and is involved in antibiotic clearance. CONCLUSIONS Our data suggests that thymol tolerance in E. coli induces morphological, metabolic and genetic changes to adapt to thymol antimicrobial activity.
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Affiliation(s)
- Fatemah Al-Kandari
- Department of Food and Nutrition Science, School of Chemistry, University of Reading, Reading, RG6 6AP UK
- Department of Plant Protection, Public Authority Of Agriculture Affairs & Fish Resources, Al-Rabia, Kuwait
| | - Rabeah Al-Temaimi
- Human Genetics Unit, Department of Pathology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Arnoud H. M. van Vliet
- Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL UK
| | - Martin J. Woodward
- Department of Food and Nutrition Science, School of Chemistry, University of Reading, Reading, RG6 6AP UK
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22
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Zhang Y, Wei J, Qiu Y, Niu C, Song Z, Yuan Y, Yue T. Structure-Dependent Inhibition of Stenotrophomonas maltophilia by Polyphenol and Its Impact on Cell Membrane. Front Microbiol 2019; 10:2646. [PMID: 31798564 PMCID: PMC6863799 DOI: 10.3389/fmicb.2019.02646] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/30/2019] [Indexed: 11/16/2022] Open
Abstract
As natural occurring antimicrobial substances, phenolic compounds have been used to inhibit various bacteria. Stenotrophomonas maltophilia 4–1, a strain isolated from food, exhibited spoilage potential in vitro with proteolysis and lipolysis at 25°C. The present study evaluated the antibacterial properties of 13 polyphenols on S. maltophilia 4–1, and selected 6 compounds (ferulic acid, p-coumaric acid, caffeic acid, chlorogenic acid, (−)-epigallocatechin, and phloretin) for binary combination treatments. The results revealed that antibacterial activities of polyphenols were structure-dependent, and cinnamic acid showed strong inhibitory effects, with a minimum inhibitory concentration (MIC) of 0.125 mg/mL. Importantly, we did not observe any obvious synergistic effects across all binary combinations. The antibacterial mechanism of cinnamic acid was related to membrane damage, caused by the loss of cell membrane integrity and alteration of cell morphology. These findings suggest that cinnamic acid is a promising candidate for the control of spoilage bacteria in food.
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Affiliation(s)
- Yuxiang Zhang
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China
| | - Jianping Wei
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China
| | - Yue Qiu
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China
| | - Chen Niu
- College of Food Science and Technology, Northwest University, Xi'an, China
| | - Zihan Song
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China
| | - Yahong Yuan
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China
| | - Tianli Yue
- College of Food Science and Engineering, Northwest A&F University, Yangling, China.,Laboratory of Quality & Safety Risk Assessment for Agro-products, Ministry of Agriculture, Yangling, China.,National Engineering Research Center of Agriculture Integration Test, Yangling, China.,College of Food Science and Technology, Northwest University, Xi'an, China
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23
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Yuan W, Yuk HG. Effects of Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde Adaptation on Virulence Properties of Escherichia coli O157:H7. Appl Environ Microbiol 2019; 85:AEM.00271-19. [PMID: 31076428 DOI: 10.1128/aem.00271-19/format/epub] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/28/2019] [Indexed: 05/27/2023] Open
Abstract
Essential oils (EOs) have demonstrated wide-spectrum antimicrobial activities and have been actively studied for their application in foods as alternative natural preservatives. However, information regarding microbial adaptive responses and changes in virulence properties following sublethal EO exposure is still scarce. The present study investigated the effect of sublethal thymol (Thy), carvacrol (Car), or trans-cinnamaldehyde (TC) adaptation on virulence gene expression and virulence properties of Escherichia coli O157:H7. The results demonstrated that E. coli O157:H7 grown to the early stationary phase in the presence of sublethal EO showed significantly (P < 0.05) reduced motility (reversible after stress removal), biofilm-forming ability, and efflux pump activity, with no induction of antibiotic resistance and no significant changes to its adhesion and invasion ability on a human colon adenocarcinoma (Caco-2) cell line. Reverse transcription-quantitative PCR revealed reduced expression of relevant virulence genes, including those encoding flagellar biosynthesis and function, biofilm formation regulators, multidrug efflux pumps, and type III secretion system components. This study demonstrated that Thy, Car, and TC at sublethal concentrations did not potentiate virulence in adapted E. coli O157:H7, which could benefit to their application in the food industry.IMPORTANCE The present study was conducted to evaluate changes in virulence properties in Escherichia coli O157:H7 adapted to sublethal essential oils (EOs). The results demonstrated reduced motility, biofilm-forming ability, and efflux pump activities in EO-adapted E. coli O157:H7, with no induction of antibiotic resistance or infection (adhesion and invasion) on Caco-2 cells. Reverse transcription-quantitative PCR results revealed changes in the expression of related virulence genes. Thus, the present study provides new insights into microbial virulence behavior following EO adaptation and suggests that Thy, Car, and TC sublethal exposure did not constitute a significant risk in inducing microbial virulence.
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Affiliation(s)
- Wenqian Yuan
- Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Singapore
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
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24
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Effects of Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde Adaptation on Virulence Properties of Escherichia coli O157:H7. Appl Environ Microbiol 2019; 85:AEM.00271-19. [PMID: 31076428 DOI: 10.1128/aem.00271-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/28/2019] [Indexed: 01/22/2023] Open
Abstract
Essential oils (EOs) have demonstrated wide-spectrum antimicrobial activities and have been actively studied for their application in foods as alternative natural preservatives. However, information regarding microbial adaptive responses and changes in virulence properties following sublethal EO exposure is still scarce. The present study investigated the effect of sublethal thymol (Thy), carvacrol (Car), or trans-cinnamaldehyde (TC) adaptation on virulence gene expression and virulence properties of Escherichia coli O157:H7. The results demonstrated that E. coli O157:H7 grown to the early stationary phase in the presence of sublethal EO showed significantly (P < 0.05) reduced motility (reversible after stress removal), biofilm-forming ability, and efflux pump activity, with no induction of antibiotic resistance and no significant changes to its adhesion and invasion ability on a human colon adenocarcinoma (Caco-2) cell line. Reverse transcription-quantitative PCR revealed reduced expression of relevant virulence genes, including those encoding flagellar biosynthesis and function, biofilm formation regulators, multidrug efflux pumps, and type III secretion system components. This study demonstrated that Thy, Car, and TC at sublethal concentrations did not potentiate virulence in adapted E. coli O157:H7, which could benefit to their application in the food industry.IMPORTANCE The present study was conducted to evaluate changes in virulence properties in Escherichia coli O157:H7 adapted to sublethal essential oils (EOs). The results demonstrated reduced motility, biofilm-forming ability, and efflux pump activities in EO-adapted E. coli O157:H7, with no induction of antibiotic resistance or infection (adhesion and invasion) on Caco-2 cells. Reverse transcription-quantitative PCR results revealed changes in the expression of related virulence genes. Thus, the present study provides new insights into microbial virulence behavior following EO adaptation and suggests that Thy, Car, and TC sublethal exposure did not constitute a significant risk in inducing microbial virulence.
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