{"title":"Antibacterial and antibiofilm activities of star anise-cinnamon essential oil against multidrug-resistant <i>Salmonella</i> Thompson.","authors":"Jie Zhang, Dapei Zhang, Yanhua Chen, Yongyu Gong, Binfang Yuan, Zhiyuan Mo, Haibo Tang, Junyu Tao, Ziheng Xu","doi":"10.3389/fcimb.2024.1463551","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>The emergence of foodborne multidrug-resistant (MDR) <i>Salmonella</i> has attracted considerable global attention. Given that food is the primary transmission route, our study focuses on <i>Bellamya quadrata</i>, a freshwater snail that is commonly consumed as a specialty food in Guangxi, China.</p><p><strong>Methods: </strong>Eight MDR <i>Salmonella</i> strains were isolated from <i>Bellamya quadrata</i> samples collected across various markets. Previous animal experiments have confirmed their lethality in mice. We determined the minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) indices of cinnamon essential oil (CEO) and star anise essential oil (SAEO) using the microdilution plate and checkerboard methods. The time-kill curve method was employed to assess the antibacterial activity of the cinnamon-star anise essential oil (SCEO) against planktonic MDR <i>Salmonella</i>. The alkaline phosphatase assay and fluorescence microscopy demonstrated that SCEO causes damage to bacterial cell walls and membranes. Crystal violet staining and scanning electron microscopy (SEM) were used to observe changes in biofilms after SCEO treatment. Quantitative real-time PCR was utilized to analyze the expression of genes related to biofilm formation following SCEO treatment.</p><p><strong>Results: </strong>The MIC of SAEO was determined to be 25 mg/mL, whereas that of CEO was significantly lower at 0.62 mg/mL. The FIC index calculated was 0.375, which suggests a synergistic interaction between the two. When SCEO was used in combination at specific ratios, it demonstrated enhanced antibacterial and anti-biofilm capabilities compared to the individual effects of CEO or SAEO, potentially through the disruption of bacterial cell membranes and cell walls. However, in <i>Salmonella</i> treated with SCEO, an upregulation in the expression of biofilm-associated genes was observed, including <i>csgA, adrA, bcsA</i>, and <i>csgD</i>. This increase may be attributed to stress-induced transcriptional responses within the bacteria.</p><p><strong>Discussion: </strong>SCEO significantly impacts cell wall integrity, suggesting its crucial role in reducing biofilm formation. These findings indicate that SCEO holds potential as an alternative to traditional antibiotics and merits further scientific investigation and development.</p>","PeriodicalId":12458,"journal":{"name":"Frontiers in Cellular and Infection Microbiology","volume":"14 ","pages":"1463551"},"PeriodicalIF":4.6000,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11911814/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Cellular and Infection Microbiology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.3389/fcimb.2024.1463551","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/1/1 0:00:00","PubModel":"eCollection","JCR":"Q2","JCRName":"IMMUNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction: The emergence of foodborne multidrug-resistant (MDR) Salmonella has attracted considerable global attention. Given that food is the primary transmission route, our study focuses on Bellamya quadrata, a freshwater snail that is commonly consumed as a specialty food in Guangxi, China.
Methods: Eight MDR Salmonella strains were isolated from Bellamya quadrata samples collected across various markets. Previous animal experiments have confirmed their lethality in mice. We determined the minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) indices of cinnamon essential oil (CEO) and star anise essential oil (SAEO) using the microdilution plate and checkerboard methods. The time-kill curve method was employed to assess the antibacterial activity of the cinnamon-star anise essential oil (SCEO) against planktonic MDR Salmonella. The alkaline phosphatase assay and fluorescence microscopy demonstrated that SCEO causes damage to bacterial cell walls and membranes. Crystal violet staining and scanning electron microscopy (SEM) were used to observe changes in biofilms after SCEO treatment. Quantitative real-time PCR was utilized to analyze the expression of genes related to biofilm formation following SCEO treatment.
Results: The MIC of SAEO was determined to be 25 mg/mL, whereas that of CEO was significantly lower at 0.62 mg/mL. The FIC index calculated was 0.375, which suggests a synergistic interaction between the two. When SCEO was used in combination at specific ratios, it demonstrated enhanced antibacterial and anti-biofilm capabilities compared to the individual effects of CEO or SAEO, potentially through the disruption of bacterial cell membranes and cell walls. However, in Salmonella treated with SCEO, an upregulation in the expression of biofilm-associated genes was observed, including csgA, adrA, bcsA, and csgD. This increase may be attributed to stress-induced transcriptional responses within the bacteria.
Discussion: SCEO significantly impacts cell wall integrity, suggesting its crucial role in reducing biofilm formation. These findings indicate that SCEO holds potential as an alternative to traditional antibiotics and merits further scientific investigation and development.
期刊介绍：
Frontiers in Cellular and Infection Microbiology is a leading specialty journal, publishing rigorously peer-reviewed research across all pathogenic microorganisms and their interaction with their hosts. Chief Editor Yousef Abu Kwaik, University of Louisville is supported by an outstanding Editorial Board of international experts. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, clinicians and the public worldwide.
Frontiers in Cellular and Infection Microbiology includes research on bacteria, fungi, parasites, viruses, endosymbionts, prions and all microbial pathogens as well as the microbiota and its effect on health and disease in various hosts. The research approaches include molecular microbiology, cellular microbiology, gene regulation, proteomics, signal transduction, pathogenic evolution, genomics, structural biology, and virulence factors as well as model hosts. Areas of research to counteract infectious agents by the host include the host innate and adaptive immune responses as well as metabolic restrictions to various pathogenic microorganisms, vaccine design and development against various pathogenic microorganisms, and the mechanisms of antibiotic resistance and its countermeasures.
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