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Ke Z, Peng X, Jia S, Liu S, Zhou X, Ding Y. Mechanisms underlying the potent antimicrobial effects of plasma-activated seawater (PASW) on fish spoilage bacterium Shewanella putrefaciens. Food Chem 2024; 455:140147. [PMID: 38905783 DOI: 10.1016/j.foodchem.2024.140147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/31/2024] [Accepted: 06/15/2024] [Indexed: 06/23/2024]
Abstract
Plasma-activated seawater (PASW) presents a promising approach for marine fish preservation, yet its antimicrobial efficacy and mechanisms remain unclear. This study found that PASW exhibits superior bactericidal properties against the fish spoilage bacterium Shewanella putrefaciens compared to plasma-activated water (PAW), and increased effectiveness in preserving fish fillets. To clarify the mechanisms, a detailed investigation was conducted, including the generation of reactive oxygen/nitrogen species (ROS/RNS) and active halogen species in PASW, and their antimicrobial efficacy. Findings showed greater nitrite and hydrogen peroxide production in PASW relative to PAW, as well as the conversion of chloride/bromide ions into active species, which collectively enhanced PASW's antimicrobial activity. The synergistic action of ROS/RNS and active chlorine/bromine species in PASW promoted the generation of intracellular ROS, causing increased membrane damage, redox imbalance, and consequently higher bacterial mortality. This study enhances our understanding of PASW's antimicrobial effects and highlights its potential applications in the seafood industry.
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Affiliation(s)
- Zhigang Ke
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China.
| | - Xingjian Peng
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China
| | - Shiliang Jia
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China
| | - Shulai Liu
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China
| | - Xuxia Zhou
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China
| | - Yuting Ding
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Key Laboratory of Green, Low-carbon and Efficient Development of Marine Fishery Resources, Hangzhou 310014, China; National R&D Branch Center for Pelagic Aquatic Products Processing (Hangzhou), Hangzhou 310014, China.
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Atasoy M, Bartkova S, Çetecioğlu-Gürol Z, P Mira N, O'Byrne C, Pérez-Rodríguez F, Possas A, Scheler O, Sedláková-Kaduková J, Sinčák M, Steiger M, Ziv C, Lund PA. Methods for studying microbial acid stress responses: from molecules to populations. FEMS Microbiol Rev 2024; 48:fuae015. [PMID: 38760882 PMCID: PMC11418653 DOI: 10.1093/femsre/fuae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 03/27/2024] [Accepted: 05/16/2024] [Indexed: 05/20/2024] Open
Abstract
The study of how micro-organisms detect and respond to different stresses has a long history of producing fundamental biological insights while being simultaneously of significance in many applied microbiological fields including infection, food and drink manufacture, and industrial and environmental biotechnology. This is well-illustrated by the large body of work on acid stress. Numerous different methods have been used to understand the impacts of low pH on growth and survival of micro-organisms, ranging from studies of single cells to large and heterogeneous populations, from the molecular or biophysical to the computational, and from well-understood model organisms to poorly defined and complex microbial consortia. Much is to be gained from an increased general awareness of these methods, and so the present review looks at examples of the different methods that have been used to study acid resistance, acid tolerance, and acid stress responses, and the insights they can lead to, as well as some of the problems involved in using them. We hope this will be of interest both within and well beyond the acid stress research community.
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Affiliation(s)
- Merve Atasoy
- UNLOCK, Wageningen University and Research, PO Box 9101, 6700 HB, the Netherlands
| | - Simona Bartkova
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Zeynep Çetecioğlu-Gürol
- Department of Industrial Biotechnology, KTH Royal Institute of Technology, Roslagstullsbacken 21 106 91 Stockholm, Stockholm, Sweden
| | - Nuno P Mira
- iBB, Institute for Bioengineering and Biosciences, Department of Bioengineering, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Conor O'Byrne
- Microbiology, School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Fernando Pérez-Rodríguez
- Department of Food Science and Tehcnology, UIC Zoonosis y Enfermedades Emergentes ENZOEM, University of Córdoba, 14014 Córdoba, Spain
| | - Aricia Possas
- Department of Food Science and Tehcnology, UIC Zoonosis y Enfermedades Emergentes ENZOEM, University of Córdoba, 14014 Córdoba, Spain
| | - Ott Scheler
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
| | - Jana Sedláková-Kaduková
- Institute of Chemistry and Environmental Sciences, University of Ss. Cyril and Methodius, 91701 Trnava, Republic of Slovakia
| | - Mirka Sinčák
- Institute of Chemistry and Environmental Sciences, University of Ss. Cyril and Methodius, 91701 Trnava, Republic of Slovakia
| | - Matthias Steiger
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Carmit Ziv
- Department of Postharvest Science, Agricultural Research Organization, Volcani Center, 7505101 Rishon LeZion, Israel
| | - Peter A Lund
- School of Biosciences and Institute of Microbiology of Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Arvaniti M, Orologas-Stavrou N, Tsitsilonis OE, Skandamis P. Induction into viable but non culturable state and outgrowth heterogeneity of Listeria monocytogenes is affected by stress history and type of growth. Int J Food Microbiol 2024; 421:110786. [PMID: 38879956 DOI: 10.1016/j.ijfoodmicro.2024.110786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 03/17/2024] [Accepted: 06/02/2024] [Indexed: 06/18/2024]
Abstract
Exposure to sublethal stresses related to food-processing may induce a heterogenous mixture of cells that co-exist, comprising healthy, sublethally injured, dormant and dead cells. Heterogeneity in survival capacity and dormancy of single cells may impede the detection of foodborne pathogens. In this study, we exposed Listeria monocytogenes Scott A strain, to peracetic acid (PAA; 20-40 ppm) and to acidic conditions (hydrochloric (HCl) and acetic (AA) acid, adjusted to pH 2.7-3.0, to evaluate the resuscitation capacity and outgrowth kinetics of metabolically active cells in two different media. Injury and the viable-but-non-culturable (VBNC) status of cells were assessed by flow cytometry using CFDA (metabolically active) and PI (dead) staining. Stressed CFDA+PI- cells were sorted on Tryptic Soy (TS) Agar or in TS broth, both supplemented with 0.6 % Yeast Extract (TSAYE or TSBYE), to evaluate culturability. Resuscitation capacity of CFDA+PI-sorted cells (10 events/well) was monitored by visual inspection on TSAYE and by optical density measurement in TSBYE for 5 days. Sorting of L. monocytogenes viable cells (CFDA+PI-) in Ringer's solution on TSAYE and TSBYE showed 100 % recovery in both media (control condition), while the mean lag time in TSBYE was 9.6 h. Treatment with 20 ppm PAA for 90 and 180 min resulted in 74.79 % and 85.82 % of non-culturable cells in TSBYE and increased the average lag time to 41.7 h and 43.8 h, respectively, compared to the control (9.6 h). The longest average lag time (79.5 h) was detected after treatment with 30 ppm PAA for 90 min, while at the same condition sorting of CFDA+PI- cells resulted in 95.05 % and 93.94 % non-culturable cells on TSAYE and TSBYE, respectively. The highest percentage of wells with non-culturable cells (96.17 %) was detected on TSAYE after treatment with 40 ppm PAA for 30 min. Fractions of VBNC cells were detected in TSBYE after treatment with HCl pH 3.0 for 60 and 240 min, and in TSAYE and TSBYE after exposure to AA pH 2.7. Treatment with AA pH 2.7 for 150-300 min increased the range of recorded lag time values compared to 60 min, from 8.6 h up to 13.3 h, as well as the mean lag times in TSBYE. Modelling of the outgrowth kinetics comparing the two types of stress (oxidative vs acid) and the two systems of growth (colonial vs planktonic) revealed that low starting concentrations hindered the detection of viable L. monocytogenes cells, either due to VBNC induction or cell heterogeneity.
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Affiliation(s)
- Marianna Arvaniti
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Nikolaos Orologas-Stavrou
- Flow Cytometry Unit, Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Ourania E Tsitsilonis
- Flow Cytometry Unit, Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece.
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Snaidr L, Mühlhahn P, Beimfohr C, Kreuzer C, Richly C, Snaidr J. Specific cultivation-independent enumeration of viable cells in probiotic products using a combination of fluorescence in situ hybridization and flow cytometry. Front Microbiol 2024; 15:1410709. [PMID: 38933029 PMCID: PMC11199854 DOI: 10.3389/fmicb.2024.1410709] [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: 04/01/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024] Open
Abstract
This study introduces an optimized integration of flow cytometry and fluorescence in situ hybridization (Flow-FISH) as an approach for the specific enumeration of gram-positive bacteria in probiotic products, overcoming the limitations of conventional methods. The enhanced Flow-FISH technique synergizes the rapid and automated capabilities of flow cytometry with the high specificity of FISH, facilitating the differentiation of viable cells at the species level within probiotic blends. By analyzing lyophilized samples of Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum, and Bifidobacterium animalis subsp. lactis, and a commercial product, the study highlights the optimized Flow-FISH protocol's advantages, including reduced hybridization times to 1.5 h and elimination of centrifugation steps. Comparative evaluations with the widely accepted enumeration methods plate count and Live/Dead (L/D) staining were conducted. The study revealed that Flow-FISH produces higher viable cell counts than plate count, thereby challenging the traditional "gold standard" by highlighting its predisposition to underestimate actual viable cell numbers. Against L/D staining, Flow-FISH achieved comparable results, which, despite the different foundational premises of each technique, confirms the accuracy and reliability of our method. In conclusion, the optimized Flow-FISH protocol represents a significant leap forward in probiotic research and quality control. This method provides a rapid, robust, and highly specific alternative for the enumeration of probiotic bacteria, surpassing traditional methodologies. Its ability to enable a more detailed and reliable analysis of probiotic products paves the way for precise quality control and research insights, underscoring its potential to improve the field significantly.
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Shin M, Na G, Kang JW, Kang DH. Application of combined treatment of peracetic acid and ultraviolet-C for inactivating pathogens in water and on surface of apples. Int J Food Microbiol 2024; 411:110519. [PMID: 38101190 DOI: 10.1016/j.ijfoodmicro.2023.110519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/06/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
In this study, a combined treatment of peracetic acid (PAA) and 280 nm Ultraviolet-C (UVC) - Light emitting diode (LED) was applied for inactivating foodborne pathogens in water and apples. The combined treatment of PAA (50 ppm) and UVC-LED showed synergistic inactivation effects against Escherichia coli O157:H7 and Listeria monocytogenes in water. In mechanism analysis, PAA/UVC-LED treatment induced more lipid peroxidation, intracellular ROS, membrane, and DNA damage than a single treatment. Among them, membrane damage was the main synergistic inactivation mechanism of combination treatment. Cell rupture and shrink of both pathogens after PAA/UVC-LED treatment were also identified through scanning electron microscope (SEM) analysis. To examine inactivation of pathogens on the surface of apples by PAA, UVC-LED, and their combined treatment, a washing system (WS) was developed and used. Through applying the WS, PAA/UVC-LED treatment effectively inactivated two pathogens in washing solution and on the surface of apples below the detection limit (3.30 log CFU/2000 mL and 2.0 log CFU/apple) within 5 min. In addition, there was no significant difference in color or firmness of apples after PAA/UVC-LED treatment (p > 0.05).
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Affiliation(s)
- Minjung Shin
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Department of Food Science and Biotechnology, Dongguk University-Seoul, 32, Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 10326, Republic of Korea
| | - Gyumi Na
- Department of Food Science and Biotechnology, Dongguk University-Seoul, 32, Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 10326, Republic of Korea
| | - Jun-Won Kang
- Department of Food Science and Biotechnology, Dongguk University-Seoul, 32, Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 10326, Republic of Korea.
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea.
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6
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Boyte ME, Benkowski A, Pane M, Shehata HR. Probiotic and postbiotic analytical methods: a perspective of available enumeration techniques. Front Microbiol 2023; 14:1304621. [PMID: 38192285 PMCID: PMC10773886 DOI: 10.3389/fmicb.2023.1304621] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/20/2023] [Indexed: 01/10/2024] Open
Abstract
Probiotics are the largest non-herbal/traditional dietary supplements category worldwide. To be effective, a probiotic strain must be delivered viable at an adequate dose proven to deliver a health benefit. The objective of this article is to provide an overview of the various technologies available for probiotic enumeration, including a general description of each technology, their advantages and limitations, and their potential for the future of the probiotics industry. The current "gold standard" for analytical quantification of probiotics in the probiotic industry is the Plate Count method (PC). PC measures the bacterial cell's ability to proliferate into detectable colonies, thus PC relies on cultivability as a measure of viability. Although viability has widely been measured by cultivability, there has been agreement that the definition of viability is not limited to cultivability. For example, bacterial cells may exist in a state known as viable but not culturable (VBNC) where the cells lose cultivability but can maintain some of the characteristics of viable cells as well as probiotic properties. This led to questioning the association between viability and cultivability and the accuracy of PC in enumerating all the viable cells in probiotic products. PC has always been an estimate of the number of viable cells and not a true cell count. Additionally, newer probiotic categories such as Next Generation Probiotics (NGPs) are difficult to culture in routine laboratories as NGPs are often strict anaerobes with extreme sensitivity to atmospheric oxygen. Thus, accurate quantification using culture-based techniques will be complicated. Another emerging category of biotics is postbiotics, which are inanimate microorganisms, also often referred to as tyndallized or heat-killed bacteria. Obviously, culture dependent methods are not suitable for these products, and alternative methods are needed for their quantification. Different methodologies provide a more complete picture of a heterogeneous bacterial population versus PC focusing exclusively on the eventual multiplication of the cells. Alternative culture-independent techniques including real-time PCR, digital PCR and flow cytometry are discussed. These methods can measure viability beyond cultivability (i.e., by measuring cellular enzymatic activity, membrane integrity or membrane potential), and depending on how they are designed they can achieve strain-specific enumeration.
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Affiliation(s)
- Marie-Eve Boyte
- NutraPharma Consulting Services Inc., Sainte-Anne-des-Plaines, QC, Canada
| | | | - Marco Pane
- Probiotical Research s.r.l., Novara, Italy
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Jordal PL, Diaz MG, Morazzoni C, Allesina S, Zogno D, Cattivelli D, Galletti S, Guidesi E, Warzée JP, Pane M. Collaborative cytometric inter-laboratory ring test for probiotics quantification. Front Microbiol 2023; 14:1285075. [PMID: 38029213 PMCID: PMC10667725 DOI: 10.3389/fmicb.2023.1285075] [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: 08/29/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. From this definition, accurate enumeration of probiotic products is a necessity. Nonetheless, this definition does not specify the methods for assessing such viability. Colony forming units is the de facto gold standard for enumerating viable in probiotic products. The notion of microbial viability has been anchored in the concept of cultivability, which refers to a cell's capacity to replicate and form colonies on agar media. However, there is a growing consensus that the term "viability" should not be exclusively tied to the ability to cultivate cells. For example, bacterial cells can exist in a Viable But Non-Culturable (VBNC) state, characterized by the maintenance of characteristics such as membrane integrity, enzymatic activity, pH gradients, and elevated levels of rRNA, despite losing the ability to form colonies. Methods Herein we present the results of a collaborative inter-laboratory ring test for cytometric bacterial quantification. Specifically, membrane integrity fluorescence flow cytometry (FFC) method and the newer impedance flow cytometry (IFC) method have been used. Both methods interrogate single cells in solution for the presence of intact membranes. FFC exploits fluorochromes that reflect the presence or absence of an intact membrane. IFC probes membrane integrity in a label-free approach by detecting membrane-induced hindrances to the propagation of electricity. Results A performance ring-test and comparison design on the FFC method showed that the method is robust against the exchange of equipment, procedures, materials, and operators. After initial method optimization with assessments of rehydration medium, wake-up duration, and phase shift gating on the individual strains, the IFC method showed good agreement with the FFC results. Specifically, we tested 6 distinct species of probiotic bacteria (3 Lactobacillus and 3 Bifidobacterium strains) finding good agreement between FFC and IFC results in terms of total and live cells. Discussion Together, these results demonstrate that flow cytometry is a reliable, precise, and user-friendly culture-independent method for bacterial enumeration.
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Affiliation(s)
| | | | | | | | | | | | - Serena Galletti
- AAT – Advanced Analytical Technologies, Fiorenzuola d’Arda, Italy
| | - Elena Guidesi
- AAT – Advanced Analytical Technologies, Fiorenzuola d’Arda, Italy
| | - Jean-Pol Warzée
- European Scientific League for Probiotics, Brussels, Belgium
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Kang SY, Cho ER, Kang DH. Inactivation of foodborne pathogens in ground pork tenderloin using 915 MHz microwave heating depending on power level. Food Res Int 2023; 173:113231. [PMID: 37803544 DOI: 10.1016/j.foodres.2023.113231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 10/08/2023]
Abstract
The main purpose of this research was to investigate the effect of power level of 915 MHz microwave heating on the inactivation of foodborne pathogens in ground pork and its bactericidal mechanism. It was demonstrated that the heating rate was proportional to the power level. For instance, the heating rates observed at microwave heating powers of 2, 3, 4, and 5 kW were 1.70, 2.77, 3.35, and 4.03℃/s, respectively. The bactericidal effect of microwave heating also significantly (P < 0.05) increased with increasing power level. In particular, when ground pork was subjected to microwave heating at 5 kW, the reduction level of pathogens was>2 log units higher than at 2 kW. To determine the bactericidal mechanism of microwave heating depending on power level, changes in transmembrane potential and DNA damage were determined using fluorescence. The extent of depolarization in membrane potential of pathogens significantly (P < 0.05) increased as power level increased. There was no significant difference in degree of DNA damage at different power levels. However, the percentage of DNA damage was>86% at all power levels. The transmembrane potential assay indicates that the bacteria exhibited dramatic pore formation on the membrane at 5 kW. Through transmission electron microscopy, the electroporation effect was enhanced as power level increased. Moreover, the quality of ground pork subjected to microwave heating at 2-5 kW was determined by measuring the moisture content, cooking loss, and texture profile.
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Affiliation(s)
- Su-Yeon Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon do 25354, Republic of Korea
| | - Eun-Rae Cho
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon do 25354, Republic of Korea
| | - Dong-Hyun Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon do 25354, Republic of Korea.
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9
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Chen H, Moraru C. Synergistic effects of sequential light treatment with 222-nm/405-nm and 280-nm/405-nm wavelengths on inactivation of foodborne pathogens. Appl Environ Microbiol 2023; 89:e0065023. [PMID: 37800967 PMCID: PMC10617431 DOI: 10.1128/aem.00650-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/14/2023] [Indexed: 10/07/2023] Open
Abstract
Light-based technologies of different wavelengths can inactivate pathogenic microorganisms, but each wavelength has its limitations. This work explores the potential of sequential treatments with different wavelengths for enhancing the disinfection performance of individual treatments by employing various bactericidal mechanisms. The effectiveness, inactivation kinetics, and bactericidal mechanisms of treatments with 222/405, 280/405, and 405 nm alone against Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium, and Pseudomonas aeruginosa were evaluated. Inactivation experiments were performed in thin liquid bacterial suspensions that were treated either individually with 48 h of 405-nm light or sequentially with (i) 30 s of 222-nm far-UV-C light, followed by 48 h of 405-nm light, or (ii) 30 s of 280-nm far-UV-C light, followed by 48 h of 405-nm light. Survivors were recovered and enumerated by standard plate counting. All inactivation curves were non-linear and followed the Weibull model (0.99 ≥ R2 ≥ 0.70). Synergistic effects were found for E. coli, L. monocytogenes, and S. Typhimurium, with maximum inactivation level increases of 2.9, 3.3, and 1.1 log CFU after the sequential treatments, respectively. Marginal synergy was found for S. aureus, and an antagonistic effect was found for P. aeruginosa after sequential treatments. Significant differences in reactive oxygen species accumulation were found (P < 0.05) after various treatment combinations, and the performance of sequential treatments was correlated with cellular oxidative damage. The sequential wavelength treatments proposed demonstrate the potential for enhanced disinfection of multiple foodborne pathogens compared with individual wavelength treatments, which can have significant food safety benefits. IMPORTANCE Nonthermal light-based technologies offer a chemical-free method to mitigate microbial contamination in the food and healthcare industries. However, each individual wavelength has different limitations in terms of efficacy and operating conditions, which limits their practical applicability. In this study, bactericidal synergism of sequential treatments with different wavelengths was identified. Pre-treatments with 280 and 222 nm enhanced the disinfection performance of follow-up 405-nm treatments for multiple foodborne pathogens by inducing higher levels of cellular membrane damage and oxidative stress. These findings deliver useful information for light equipment manufacturers, food processors, and healthcare users, who can design and optimize effective light-based systems to realize the full potential of germicidal light technologies. The results from the sequential treatments offer practical solutions to improve the germicidal efficacy of visible light systems, as well as provide inspiration for future hurdle disinfection systems design, with a positive impact on food safety and public health.
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Affiliation(s)
- Hanyu Chen
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Carmen Moraru
- Department of Food Science, Cornell University, Ithaca, New York, USA
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10
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Zhang J, Ren L, Zhang L, Gong Y, Xu T, Wang X, Guo C, Zhai L, Yu X, Li Y, Zhu P, Chen R, Jing X, Jing G, Zhou S, Xu M, Wang C, Niu C, Ge Y, Ma B, Shang G, Cui Y, Yao S, Xu J. Single-cell rapid identification, in situ viability and vitality profiling, and genome-based source-tracking for probiotics products. IMETA 2023; 2:e117. [PMID: 38867931 PMCID: PMC10989769 DOI: 10.1002/imt2.117] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/22/2023] [Accepted: 05/07/2023] [Indexed: 06/14/2024]
Abstract
Rapid expansion of the probiotics industry demands fast, sensitive, comprehensive, and low-cost strategies for quality assessment. Here, we introduce a culture-free, one-cell-resolution, phenome-genome-combined strategy called Single-Cell Identification, Viability and Vitality tests, and Source-tracking (SCIVVS). For each cell directly extracted from the product, the fingerprint region of D2O-probed single-cell Raman spectrum (SCRS) enables species-level identification with 93% accuracy, based on a reference SCRS database from 21 statutory probiotic species, whereas the C-D band accurately quantifies viability, metabolic vitality plus their intercellular heterogeneity. For source-tracking, single-cell Raman-activated Cell Sorting and Sequencing can proceed, producing indexed, precisely one-cell-based genome assemblies that can reach ~99.40% genome-wide coverage. Finally, we validated an integrated SCIVVS workflow with automated SCRS acquisition where the whole process except sequencing takes just 5 h. As it is >20-fold faster, >10-time cheaper, vitality-revealing, heterogeneity-resolving, and automation-prone, SCIVVS is a new technological and data framework for quality assessment of live-cell products.
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Affiliation(s)
- Jia Zhang
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Lihui Ren
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- College of Information Science & EngineeringOcean University of ChinaQingdaoShandongChina
| | - Lei Zhang
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- Qingdao Branch of China United Network Communications Co., Ltd.QingdaoShandongChina
| | - Yanhai Gong
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Teng Xu
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xiaohang Wang
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Cheng Guo
- Eastsea Pharma Co., Ltd.QingdaoShandongChina
| | - Lei Zhai
- China National Research Institute of Food and Fermentation Industries Co., Ltd., China Center of Industrial Culture CollectionBeijingChina
| | - Xuejian Yu
- China National Research Institute of Food and Fermentation Industries Co., Ltd., China Center of Industrial Culture CollectionBeijingChina
| | - Ying Li
- Qingdao Single‐Cell Biotech. Co., Ltd.QingdaoShandongChina
| | - Pengfei Zhu
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Qingdao Single‐Cell Biotech. Co., Ltd.QingdaoShandongChina
| | - Rongze Chen
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xiaoyan Jing
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Gongchao Jing
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | - Shiqi Zhou
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
| | - Mingyue Xu
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
| | - Chen Wang
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
| | | | - Yuanyuan Ge
- China National Research Institute of Food and Fermentation Industries Co., Ltd., China Center of Industrial Culture CollectionBeijingChina
| | - Bo Ma
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
| | | | - Yunlong Cui
- Eastsea Pharma Co., Ltd.QingdaoShandongChina
| | - Su Yao
- China National Research Institute of Food and Fermentation Industries Co., Ltd., China Center of Industrial Culture CollectionBeijingChina
| | - Jian Xu
- Single‐Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdaoShandongChina
- Shandong Energy InstituteQingdaoShandongChina
- Qingdao New Energy Shandong LaboratoryQingdaoShandongChina
- University of Chinese Academy of SciencesBeijingChina
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11
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Huang YP, Shi JY, Luo SC, Xu SY, Zhang JD, Molnár I, Yang QQ, Zhang BB. Antimicrobial Substances and Mechanisms of Lactobacillus rhamnosus against Gardnerella vaginalis. Probiotics Antimicrob Proteins 2023; 15:400-410. [PMID: 36459386 DOI: 10.1007/s12602-022-10019-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2022] [Indexed: 12/04/2022]
Abstract
Bacterial vaginosis (BV) is a common vaginal disease associated with abnormal changes in the vaginal microbiome. Our previous study found that Lactobacillus rhamnosus has a good therapeutic effect on bacterial vaginosis by inhibiting the most prominent bacterium associated with BV, Gardnerella vaginalis. In this study, we show that acetic acid and lactic acid are the main substances in the cell-free supernatant (CFS) of L. rhamnosus that inhibit the growth of G. vaginalis. Further study on the mechanism showed that acetic acid and lactic acid alter the morphology of the G. vaginalis cells, eventually causing the cells to shrink or burst, resulting in exudation of their intracellular contents. In addition, these two organic acids also dissipate the membrane potential of bacterial cells, affecting their synthesis of ATP. A reduced activity of the Na+/K+-ATPase leads to abnormal ATP metabolism, and ultimately inhibits the growth and reproduction of G. vaginalis. Our study provides valuable information for the widespread application of L. rhamnosus in the treatment of bacterial vaginosis.
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Affiliation(s)
- Yu-Ping Huang
- Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, People's Republic of China
| | - Jie-Yan Shi
- Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, People's Republic of China
| | - Si-Chen Luo
- Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, People's Republic of China
| | - Shao-Yan Xu
- Qiangji Pharmaceutical Co., Ltd., 515638, Guangdong, People's Republic of China
- Longchuangji Pharmaceutical Co., Ltd., 521021, Guangdong, People's Republic of China
| | - Jia-Dong Zhang
- Qiangji Pharmaceutical Co., Ltd., 515638, Guangdong, People's Republic of China
- Longchuangji Pharmaceutical Co., Ltd., 521021, Guangdong, People's Republic of China
| | - István Molnár
- VTT Technical Research Centre of Finland, FI-02044, VTT, Espoo, Finland
| | - Qiong-Qiong Yang
- Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, People's Republic of China
| | - Bo-Bo Zhang
- Department of Biology, College of Science, Shantou University, Shantou 515063, Guangdong, People's Republic of China.
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12
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Jyung S, Kang JW, Kang DH. Inactivation of Listeria monocytogenes through the synergistic interaction between plasma-activated water and organic acid. Food Res Int 2023; 167:112687. [PMID: 37087257 DOI: 10.1016/j.foodres.2023.112687] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/24/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
This study observed that when plasma-activated water (PAW) was combined with organic acid, it showed a synergistic inactivation effect on Listeria monocytogenes, which is highly resistant to PAW. When comparing various organic acids, lactic acid (LA) showed the greatest synergistic effect, followed by malic acid (MA), citric acid (CA), and acetic acid (AA), whereas propionic acid (PA) did not show a synergistic effect. Organic acid lowered the activity of ROS defense enzymes (catalase, superoxide dismutase) by reducing intracellular pH (pHi), which induced the increase in the accumulation of ROS of PAW within the cell. In the end, the synergistic inactivation effect appeared as the increased occurrence of oxidative damage when organic acid was combined as a series of preceding causes. In this case, LA with the greatest ability to lower the pH induced the greatest synergistic effect, suggesting that LA is the best candidate to be combined with PAW. As a result of observing changes in inactivation activity for L. monocytogenes of PAW combined with 1.0% LA while storing at - 80, -20, 4, 25, & 37 °C for 30 days, respectively, it was confirmed that the lower the temperature, the lower the activity loss during the storage period, and that it had an activity of 3.72 log reduction based on 10 min treatment when stored at - 80 °C for 30 days. Application of PAW combined with 1.0% LA stored at - 80 °C for 30 days to mackerel inoculated with L. monocytogenes in ice form resulted in a decrease of 4.53 log after 120 min treatment, without changing the quality of mackerel. These results suggest that combining LA with PAW can be an effective control strategy for L. monocytogenes with high resistance to PAW, and can be effectively utilized, even in ice form.
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13
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TiO2-based photocatalyst Generated Reactive Oxygen Species cause cell membrane disruption of Staphylococcus aureus and Escherichia coli O157:H7. Food Microbiol 2023; 109:104119. [DOI: 10.1016/j.fm.2022.104119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/16/2022] [Accepted: 08/16/2022] [Indexed: 11/22/2022]
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14
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Han JY, Park SH, Kang DH. Effects of plasma bubble-activated water on the inactivation against foodborne pathogens on tomatoes and its wash water. Food Control 2023. [DOI: 10.1016/j.foodcont.2022.109381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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15
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Deciphering the induction of Listeria monocytogenes into sublethal injury using fluorescence microscopy and RT-qPCR. Int J Food Microbiol 2023; 385:109983. [DOI: 10.1016/j.ijfoodmicro.2022.109983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 10/16/2022] [Accepted: 10/17/2022] [Indexed: 11/22/2022]
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16
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Synergistic antimicrobial effects of Dryopteris erythrosora extract and mild heat treatment against Staphylococcus aureus. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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17
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Wen D, Jiang Y, Chen D. Evaluating disinfection performance of ultraviolet light-emitting diodes against the microalga Tetraselmis sp.: Assay methods, inactivation efficiencies, and action spectrum. CHEMOSPHERE 2022; 308:136113. [PMID: 36007732 DOI: 10.1016/j.chemosphere.2022.136113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 07/05/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Ultraviolet light-emitting diodes (UV-LEDs) are among the most compact devices and safest technologies in water disinfection systems. However, the validation of different assay methods to evaluate the disinfection performance of different wavelengths (265, 280, 285, and 300 nm) of UV-LEDs toward marine microalgae remains poorly characterized. In this study, several detection assays, namely the culture-based most probable number (MPN) assay, membrane integrity-based vital stain (VS) assay, chlorophyll fluorescence assay, and photochemical efficiency assay, were compared to assess the viability of the marine microalga Tetraselmis sp., with results indicating the MPN assay to be the most sensitive. In addition, this study compared the inactivation kinetics, inactivation efficiency, and energy efficiency of Tetraselmis sp. under different UV wavelengths, as assessed by the VS and MPN assays. The fluence-response curves of Tetraselmis sp. varied with assay and wavelength, with Geeraerd's model fitting all fluence-response microalgal inactivation curves. The results showed a non-significant difference in inactivation efficiency among different wavelengths of UV-LEDs (except for 300 nm) when using the VS assay. On the contrary, significant differences among all wavelengths were observed with respect to inactivation efficiency when using the MPN assay. The wavelength of 265 nm exhibited maximum inactivation efficiency, whereas 285 nm achieved optimal energy efficiency. The UV action spectrum of Tetraselmis sp. exhibited the peak at 265 nm, a finding which matched well with the absorbance spectrum of DNA. The observations from this study provide a theoretical basis and technical support for the application of the emerging UV-LED light sources in the algicidal treatment of marine water.
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Affiliation(s)
- Diya Wen
- School of Environment, Tsinghua University, Beijing, 100084, China; Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Yuelu Jiang
- School of Environment, Tsinghua University, Beijing, 100084, China; Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
| | - Daoyi Chen
- School of Environment, Tsinghua University, Beijing, 100084, China; Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
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18
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Trinh KTL, Lee NY. Recent Methods for the Viability Assessment of Bacterial Pathogens: Advances, Challenges, and Future Perspectives. Pathogens 2022; 11:1057. [PMID: 36145489 PMCID: PMC9500772 DOI: 10.3390/pathogens11091057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 11/28/2022] Open
Abstract
Viability assessment is a critical step in evaluating bacterial pathogens to determine infectious risks to public health. Based on three accepted viable criteria (culturability, metabolic activity, and membrane integrity), current viability assessments are categorized into three main strategies. The first strategy relies on the culturability of bacteria. The major limitation of this strategy is that it cannot detect viable but nonculturable (VBNC) bacteria. As the second strategy, based on the metabolic activity of bacteria, VBNC bacteria can be detected. However, VBNC bacteria sometimes can enter a dormant state that allows them to silence reproduction and metabolism; therefore, they cannot be detected based on culturability and metabolic activity. In order to overcome this drawback, viability assessments based on membrane integrity (third strategy) have been developed. However, these techniques generally require multiple steps, bulky machines, and laboratory technicians to conduct the tests, making them less attractive and popular applications. With significant advances in microfluidic technology, these limitations of current technologies for viability assessment can be improved. This review summarized and discussed the advances, challenges, and future perspectives of current methods for the viability assessment of bacterial pathogens.
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Affiliation(s)
- Kieu The Loan Trinh
- Department of Industrial Environmental Engineering, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Korea
| | - Nae Yoon Lee
- Department of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Korea
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19
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Murray EJ, Dubern JF, Chan WC, Chhabra SR, Williams P. A Pseudomonas aeruginosa PQS quorum-sensing system inhibitor with anti-staphylococcal activity sensitizes polymicrobial biofilms to tobramycin. Cell Chem Biol 2022; 29:1187-1199.e6. [PMID: 35259345 PMCID: PMC9605878 DOI: 10.1016/j.chembiol.2022.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 07/16/2021] [Accepted: 02/15/2022] [Indexed: 12/23/2022]
Abstract
As single- and mixed-species biofilms, Staphylococcus aureus and Pseudomonas aeruginosa cause difficult-to-eradicate chronic infections. In P. aeruginosa, pseudomonas quinolone (PQS)-dependent quorum sensing regulates virulence and biofilm development that can be attenuated via antagonists targeting the transcriptional regulator PqsR (MvfR). Here, we exploited a quinazolinone (QZN) library including PqsR agonists and antagonists for their activity against S. aureus alone, when co-cultured with P. aeruginosa, and in combination with the aminoglycoside tobramycin. The PqsR inhibitor, QZN 34 killed planktonic Gram-positives but not Gram-negatives. QZN 34 prevented S. aureus biofilm formation, severely damaged established S. aureus biofilms, and perturbed P. aeruginosa biofilm development. Although P. aeruginosa protected S. aureus from tobramycin in mixed biofilms, the combination of aminoglycoside antibiotic with QZN 34 eradicated the mixed-species biofilm. The mechanism of action of QZN 34 toward Gram-positive bacteria is shown to involve membrane perturbation and dissipation of transmembrane potential.
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Affiliation(s)
- Ewan J Murray
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Jean-Frédéric Dubern
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Weng C Chan
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Siri Ram Chhabra
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Paul Williams
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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20
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Jyung S, Kang JW, Kang DH. L. monocytogens exhibited less cell membrane damage, lipid peroxidation, and intracellular reactive oxygen species accumulation after plasma-activated water treatment compared to E. coli O157:H7 and S. Typhimurium. Food Microbiol 2022; 108:104098. [DOI: 10.1016/j.fm.2022.104098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 11/04/2022]
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21
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Wang W, Wang X, Liu J, Lin C, Liu J, Wang J. The Integration of Gold Nanoparticles with Polymerase Chain Reaction for Constructing Colorimetric Sensing Platforms for Detection of Health-Related DNA and Proteins. BIOSENSORS 2022; 12:bios12060421. [PMID: 35735568 PMCID: PMC9220820 DOI: 10.3390/bios12060421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 05/02/2023]
Abstract
Polymerase chain reaction (PCR) is the standard tool in genetic information analysis, and the desirable detection merits of PCR have been extended to disease-related protein analysis. Recently, the combination of PCR and gold nanoparticles (AuNPs) to construct colorimetric sensing platforms has received considerable attention due to its high sensitivity, visual detection, capability for on-site detection, and low cost. However, it lacks a related review to summarize and discuss the advances in this area. This perspective gives an overview of established methods based on the combination of PCR and AuNPs for the visual detection of health-related DNA and proteins. Moreover, this work also addresses the future trends and perspectives for PCR-AuNP hybrid biosensors.
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Affiliation(s)
- Wanhe Wang
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
- Innovation Center NPU Chongqing, Northwestern Polytechnical University, Chongqing 400000, China
| | - Xueliang Wang
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
- Innovation Center NPU Chongqing, Northwestern Polytechnical University, Chongqing 400000, China
| | - Jingqi Liu
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
| | - Chuankai Lin
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
| | - Jianhua Liu
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
| | - Jing Wang
- Institute of Medical Research, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China; (W.W.); (X.W.); (J.L.); (C.L.); (J.L.)
- Research & Development Institute of Northwestern Polytechnical University in Shenzhen, 45 South Gaoxin Road, Shenzhen 518057, China
- Collaborative Innovation Center of NPU, Shanghai 201100, China
- Innovation Center NPU Chongqing, Northwestern Polytechnical University, Chongqing 400000, China
- Correspondence: ; Tel.: +86-13268283561
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22
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Bouix M, Ghorbal S, Picque D, Perret B, Saulou-Berion C. A rapid method for the assessment of the vitality of microorganisms using flow cytometry. Cytometry A 2022; 101:577-587. [PMID: 35324070 DOI: 10.1002/cyto.a.24553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/25/2022] [Accepted: 03/15/2022] [Indexed: 11/06/2022]
Abstract
Cultivability, viability and vitality make it possible to characterize the behavior of a cellular population. Vitality was assessed using the kinetic parameters of specific metabolisms depending on whether the strains were used, for example, for the acidification of lactic acid bacteria or for CO2 production in fermenting yeasts. However, these methods are time-consuming. We developed a cytometric descriptor based on the energy-dependent extrusion of carboxyfluorescein from cells, subsequent to carboxyfluorescein diacetate staining, and compared it to the measurements of metabolic activities of various bacteria and yeasts. For all of the microorganisms tested, the cytometric descriptor ΔFI15 was well correlated with the results of the metabolic measurements and, moreover, has the advantage of being easier and faster to use than metabolic methods. It can be very useful for evaluating the vitality of the starters before inoculation in industrial processes. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Marielle Bouix
- Université Paris-Saclay, AgroParisTech, INRAe, UMR SayFood, Thiverval-Grignon, France
| | - Sarrah Ghorbal
- Université Paris-Saclay, AgroParisTech, INRAe, UMR SayFood, Thiverval-Grignon, France
| | - Daniel Picque
- Université Paris-Saclay, AgroParisTech, INRAe, UMR SayFood, Thiverval-Grignon, France
| | - Bruno Perret
- Université Paris-Saclay, AgroParisTech, INRAe, UMR SayFood, Thiverval-Grignon, France
| | - Claire Saulou-Berion
- Université Paris-Saclay, AgroParisTech, INRAe, UMR SayFood, Thiverval-Grignon, France
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23
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Live-dead assay on unlabeled cells using phase imaging with computational specificity. Nat Commun 2022; 13:713. [PMID: 35132059 PMCID: PMC8821584 DOI: 10.1038/s41467-022-28214-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 01/11/2022] [Indexed: 12/20/2022] Open
Abstract
Existing approaches to evaluate cell viability involve cell staining with chemical reagents. However, the step of exogenous staining makes these methods undesirable for rapid, nondestructive, and long-term investigation. Here, we present an instantaneous viability assessment of unlabeled cells using phase imaging with computation specificity. This concept utilizes deep learning techniques to compute viability markers associated with the specimen measured by label-free quantitative phase imaging. Demonstrated on different live cell cultures, the proposed method reports approximately 95% accuracy in identifying live and dead cells. The evolution of the cell dry mass and nucleus area for the labeled and unlabeled populations reveal that the chemical reagents decrease viability. The nondestructive approach presented here may find a broad range of applications, from monitoring the production of biopharmaceuticals to assessing the effectiveness of cancer treatments. Common methods for characterising cell viability involve cell staining with chemical reagents. Here the authors report a method for cell viability assessment that does not require labelling; this uses quantitative phase imaging combined with deep learning.
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24
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Wendel U. Assessing Viability and Stress Tolerance of Probiotics—A Review. Front Microbiol 2022; 12:818468. [PMID: 35154042 PMCID: PMC8829321 DOI: 10.3389/fmicb.2021.818468] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/27/2021] [Indexed: 11/26/2022] Open
Abstract
The interest in probiotics has increased rapidly the latest years together with the global market for probiotic products. Consequently, establishing reliable microbiological methods for assuring the presence of a certain number of viable microorganisms in probiotic products has become increasingly important. To assure adequate numbers of viable cells, authorities are enquiring for information on viability rates within a certain shelf-life in colony forming units (CFU). This information is obtained from plate count enumeration, a method that enables detection of bacterial cells based on their ability to replicate. Although performing plate count enumeration is one manner of assessing viability, cells can still be viable without possessing the ability to replicate. Thus, to properly assess probiotic viability, further analysis of a broader group of characteristics using several types of methods is proposed. In addition to viability, it is crucial to identify how well the cells in a probiotic product can survive in the gastrointestinal tract (GIT) and thus be able to mediate the desired health benefit while passing through the human body. A broad spectrum of different assay designs for assessing probiotic gastric tolerance have been used in research and quality control. However, the absence of any consensus on how to assess these qualities makes it difficult to compare between laboratories and to translate the results into in vivo tolerance. This review presents and discusses the complexity of assuring that a probiotic is suitable for beneficial consumption. It summarizes the information that can be subtracted from the currently available methods for assessment of viability and stress tolerance of a probiotic, hereby altogether defined as “activity.” Strengths and limitations of the different methods are presented together with favorable method combinations. Finally, the importance of choosing a set of analyses that reveals the necessary aspects of probiotic activity for a certain product or application is emphasized.
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Synergistic Antimicrobial Effect of UV-A Irradiation and Malic Acid Combination Treatment Against Foodborne Pathogens on Spinach and the Underlying Mechanism. FOOD BIOPROCESS TECH 2022. [DOI: 10.1007/s11947-021-02662-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants. Microbiol Spectr 2021; 9:e0137721. [PMID: 34908469 PMCID: PMC8672913 DOI: 10.1128/spectrum.01377-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The dormancy continuum hypothesis states that in response to stress, cells enter different stages of dormancy ranging from unstressed living cells to cell death, in order to ensure their long-term survival under adverse conditions. Exposure of Listeria monocytogenes cells to sublethal stressors related to food processing may induce sublethal injury and the viable-but-nonculturable (VBNC) state. In this study, exposure to acetic acid (AA), hydrochloric acid (HCl), and two disinfectants, peracetic acid (PAA) and sodium hypochlorite (SH), at 20°C and 4°C was used to evaluate the potential induction of L. monocytogenes strain Scott A into different stages of dormancy. To differentiate the noninjured subpopulation from the total population, tryptic soy agar with 0.6% yeast extract (TSAYE), supplemented or not with 5% NaCl, was used. Sublethally injured and VBNC cells were detected by comparing plate counts obtained with fluorescence microscopy and by using combinations of carboxyfluorescein and propidium iodide (viable/dead cells). Induction of sublethal injury was more intense after PAA treatment. Two subpopulations were detected, with phenotypes of untreated cells and small colony variants (SCVs). SCVs appeared as smaller colonies of various sizes and were first observed after 5 min of exposure to 5 ppm PAA at 20°C. Increasing the stress intensity from 5 to 40 ppm PAA led to earlier detection of SCVs. L. monocytogenes remained culturable after exposure to 20 and 30 ppm PAA for 3 h. At 40 ppm, after 3 h of exposure, the whole population was considered nonculturable, while cells remained metabolically active. These results corroborate the induction of the VBNC state. IMPORTANCE Sublethally injured and VBNC cells may evade detection, resulting in underestimation of a food product's microbial load. Under favorable conditions, cells may regain their growth capacity and acquire new resistant characteristics, posing a major threat for public health. Induction of the VBNC state is crucial for foodborne pathogens, such as L. monocytogenes, the detection of which relies almost exclusively on the use of culture recovery techniques. In the present study, we confirmed that sublethal injury is an initial stage of dormancy in L. monocytogenes that is followed by the VBNC state. Our results showed that PAA induced SCVs (a phenomenon potentially triggered by external factors) and the VBNC state in L. monocytogenes, indicating that tests of lethality based only on culturability may provide false-positive results regarding the effectiveness of an inactivation treatment.
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Borjihan Q, Wu H, Dong A, Gao H, Yang Y. AIEgens for Bacterial Imaging and Ablation. Adv Healthc Mater 2021; 10:e2100877. [PMID: 34342176 DOI: 10.1002/adhm.202100877] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/04/2021] [Indexed: 12/15/2022]
Abstract
Accurate and sensitive diagnosis of pathogenic bacterial infection is a fundamental first step for correct bacteria management, helping to avoid the development of drug-resistant bacteria caused by the inappropriate use and overuse of antibiotics. Fluorescence probes as a promising visual tool can help identify pathogens rapidly and reliably. However, rigidly structured traditional fluorescence probes generally suffer from the drawback of aggregation-caused quenching (ACQ) effect, which greatly undermines their advantages with respect to sensitivity. Luminogens with aggregation-induced emission properties, namely AIEgens, can overcome the ACQ effect and certain AIEgen-based materials are capable of generating reactive oxygen species (ROS) in the aggregate states. Hence, they have become powerful tools for imaging and killing bacteria. This review summarizes the recent advances in AIEgens for the diagnosis and treatment of pathogen infections. Special attention has been paid to the molecular design, the application in bacterial imaging and ablation in vitro and in vivo, and the biocompatibility of AIEgens. Finally, the challenges and prospects are discussed in terms of using AIEgens to advance precision therapies for pathogen infections.
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Affiliation(s)
- Qinggele Borjihan
- College of Chemistry and Chemical Engineering Engineering Research Center of Dairy Quality and Safety Control Technology Ministry of Education Inner Mongolia University Hohhot 010021 P. R. China
| | - Haixia Wu
- College of Chemistry and Chemical Engineering Engineering Research Center of Dairy Quality and Safety Control Technology Ministry of Education Inner Mongolia University Hohhot 010021 P. R. China
| | - Alideertu Dong
- College of Chemistry and Chemical Engineering Engineering Research Center of Dairy Quality and Safety Control Technology Ministry of Education Inner Mongolia University Hohhot 010021 P. R. China
| | - Hui Gao
- State Key Laboratory of Separation Membranes and Membrane Processes School of Materials Science and Engineering Tiangong University Tianjin 300387 P. R. China
| | - Ying‐Wei Yang
- International Joint Research Laboratory of Nano‐Micro Architecture Chemistry College of Chemistry Jilin University 2699 Qianjin Street Changchun 130012 P. R. China
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M de Araújo FB, Morais VC, M de Oliveira BT, G de Lima KY, Gomes VT, G do Amaral IP, Vasconcelos U. Multi-purpose Disinfecting Solutions only Partially Inhibit the Development of Ocular Microbes Biofilms in Contact Lens Storage Cases. Middle East Afr J Ophthalmol 2021; 28:116-122. [PMID: 34759670 PMCID: PMC8547665 DOI: 10.4103/meajo.meajo_414_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/28/2021] [Accepted: 07/14/2021] [Indexed: 10/26/2022] Open
Abstract
PURPOSE Certain ocular resident or pathogenic microbes may remain viable in the presence of multi-purpose disinfectant solutions (MPDSs), subsequently developing biofilms inside contact lens storage cases (CLSCs) which pose a risk of infection to wearers. This study evaluated the formation of ocular microbiota biofilms exposed to three top selling MPDS. METHODS Crystal violet assay was carried out for the verification of biofilm formation. The in vitro assays evaluated Pseudomonas aeruginosa UFPEDA 416 and Staphylococcus aureus UFPEDA 02 exposure of 48 h to MPDS, as well as the use of 40 KHz ultrasound at the beginning and with 24 h immersion in the MPDS. Subsequently, in vivo assays evaluated the formation of microbial biofilms on the CLSC walls containing silicone-hydrogel contact lenses immersed in MPDS from 15 healthy volunteer patients, who had been wearing the lenses for 7 days. RESULTS Biofilms were inhibited by 26%-98% in the in vitro assays, with a statistically significant difference only for P. aeruginosa UFPEDA 416 exposed to diluted MPDS. Most inhibitions occurred moderately and weakly. In addition, adherent cells were detected in more than 90% of the tests. Biofilm was not inhibited in more than one third of the results, nor was it disturbed, especially with the ultrasound treatments. The average of obtained optical densities at 590 nm was between 0.6 and 0.8 in the in vivo assays. The results were similar between the CLSC right and left wells. There was a correlation between microbial biofilm formation and the type of MPDS tested, with statistical difference between the three treatments. CONCLUSION MPDS promoted a partial inhibition of microbial biofilm formation but only one MPDS proved to be more effective in vitro and in vivo. This study, however, could not distinguish the effect of possible errors in the good hygiene practices of the users.
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Affiliation(s)
- Fabiano B M de Araújo
- Department of Molecular Biology, Curse of Post-Graduation in Cellular and Molecular Biology, CCEN, UFPB, João Pessoa, Brazil
| | - Vinicius C Morais
- Department of Biotechnology, Laboratory of Environmental Microbiology, CBIOTEC, UFPB, João Pessoa, Brazil
| | - Bianca T M de Oliveira
- Department of Biotechnology, Laboratory of Environmental Microbiology, CBIOTEC, UFPB, João Pessoa, Brazil
| | - Kaíque Y G de Lima
- Department of Biotechnology, Laboratory of Environmental Microbiology, CBIOTEC, UFPB, João Pessoa, Brazil
| | - Victor T Gomes
- Department of Biotechnology, Laboratory of Environmental Microbiology, CBIOTEC, UFPB, João Pessoa, Brazil
| | - Ian P G do Amaral
- Department of Cellular and Molecular Biology, Laboratory of Biotechnology of Aquatic Organisms, CBIOTEC, UFPB, João Pessoa, Brazil
| | - Ulrich Vasconcelos
- Department of Biotechnology, Laboratory of Environmental Microbiology, CBIOTEC, UFPB, João Pessoa, Brazil
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Luo X, Xu X, Cao R, Wan Q, Wang J, Xu H, Lin Y, Wen G, Huang T. The formation kinetics and control of biofilms by three dominant fungi species isolated from groundwater. J Environ Sci (China) 2021; 109:148-160. [PMID: 34607663 DOI: 10.1016/j.jes.2021.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 06/13/2023]
Abstract
Filamentous fungi can enter drinking water supply systems in various ways, and exist in suspended or sessile states which threatens the health of individuals by posing a high risk of invasive infections. In this study, the biofilms formation kinetics of the three genera of fungal spores, Aspergillus niger (A. niger), Penicillium polonicum (P. polonicum) and Trichoderma harzianum (T. harzianum) isolated from the groundwater were reported, as well as the effects of water quality parameters were evaluated. In addition, the efficiency of low- concentrations of chlorine-based disinfectants (chlorine, chlorine dioxide and chloramine) on controlling the formation of fungal biofilms was assessed. The results showed that the biofilms formation of the three genera of fungi could be divided into the following four phases: induction, exponential, stationary and sloughing off. The optimum conditions for fungal biofilms formation were found to be neutral or weakly acidic at 28 °C with rich nutrition. In fact, A. niger, P. polonicum, and T. harzianum were not observed to form mature biofilms in actual groundwater within 120 hr. Carbon was found to have the maximum effect on the fungal biofilms formation in actual groundwater, followed by nitrogen and phosphorus. The resistance of fungal species to disinfectants during the formation of biofilms decreased in the order: A. niger > T. harzianum > P. polonicum. Chlorine dioxide was observed to control the biofilms formation with maximum efficiency, followed by chlorine and chloramine. Consequently, the results of this study will provide a beneficial understanding for the formation and control of fungal biofilms.
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Affiliation(s)
- Xinyu Luo
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xiangqian Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ruihua Cao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Qiqi Wan
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Jingyi Wang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Huining Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yingzi Lin
- School of Municipal and Environmental Engineering, Jilin Jianzhu University, Changchun 130118, China
| | - Gang Wen
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Tinglin Huang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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Shi C, Knøchel S. Inhibitory effects of binary combinations of microbial metabolites on the growth of tolerant Penicillium roqueforti and Mucor circinelloides. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.112039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Yang X, Dai X, Jin H, Lin G, Wang Z, Song Y, Zhang W, Man C, Jiang Y. Physicochemical and transcriptomic responses of Lactobacillus brevis JLD715 to sodium selenite. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2021; 101:4332-4341. [PMID: 33417239 DOI: 10.1002/jsfa.11073] [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: 08/26/2020] [Revised: 12/15/2020] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Elemental selenium, as a new type of selenium supplement, can be prepared by microorganisms reducing inorganic selenium. In this study, Lactobacillus brevis JLD715 was incubated in broth containing different concentrations of sodium selenite (Na2 SeO3 ). RESULTS The results showed that the bacterial biomass of L. brevis JLD715 decreased due to the inhibition of Na2 SeO3 . The cell membrane of L. brevis JLD715 treated with Na2 SeO3 was damaged, as evidenced by the reduction of intracellular ATP concentration, depolarization of cell membrane, reduction of intracellular pH and impairment of membrane integrity. In addition, we investigated the metabolism mechanism of Na2 SeO3 by L. brevis JLD715 based on transcriptome sequencing. A total of 461 genes were significantly differentially expressed under Na2 SeO3 treatment, of which 231 genes were up-regulated and 230 genes were down-regulated. These genes were involved in pathways such as pyruvate metabolism, fatty acid biosynthesis, selenocompound metabolism and nucleotide-binding oligomerization domain-like (NOD-like) receptor signaling. Meanwhile, the genes related to sulfhydryl oxidoreductase, electron carrier proteins and transmembrane transport proteins synthesis were significantly up-regulated. CONCLUSION To sum up, the findings of this research will contribute to providing support for the application of L. brevis JLD715 in selenium-enriched functional foods. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Xiaofei Dai
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Haonan Jin
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Guangen Lin
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Zhenghui Wang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Yang Song
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Wei Zhang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin, China
- Kangyuan Dairy Co. Ltd, Yangzhou University, Yangzhou, China
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Seo YS, Lee G, Song S, Kim K, Cho M. Combinatorial treatment using citric acid, malic acid, and phytic acid for synergistical inactivation of foodborne pathogenic bacteria. KOREAN J CHEM ENG 2021. [DOI: 10.1007/s11814-021-0751-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cho GL, Ha JW. Synergistic effect of citric acid and xenon light for inactivating foodborne pathogens on spinach leaves. Food Res Int 2021; 142:110210. [PMID: 33773673 DOI: 10.1016/j.foodres.2021.110210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 01/28/2021] [Accepted: 01/30/2021] [Indexed: 11/16/2022]
Abstract
The aim of this study was to evaluate the synergistic antimicrobial effect of xenon light (XL) and citric acid (CA) combination against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on spinach leaves and determine the effect of XL-CA combination on quality of spinach leaves. The XL-CA combined treatment for 8 min synergistically decreased the cell counts of E. coli O157:H7 and S. Typhimurium by 5.25 and 5.05 log CFU/cm2, respectively, and additively decreased the L. monocytogenes cells by 5.02 log unit on spinach. The mechanisms underlying synergistic lethal effect of the XL-CA combination were investigated. Qualitative and quantitative analyses revealed that the bacterial cell membrane damage was strongly associated with the synergistic antimicrobial effect of the XL-CA combination. Additionally, treatment with XL-CA combination for 8 min did not affect the quality attributes (color, total phenol contents, and texture) of spinach leaves. These results suggest that the XL-CA combination treatment can be effectively used to control major pathogens on fresh produce.
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Affiliation(s)
- Ga-Lam Cho
- Department of Food Science and Biotechnology, Global K-Food Research Center, Hankyong National University, Anseong-si 17579, South Korea
| | - Jae-Won Ha
- Department of Food Science and Biotechnology, Global K-Food Research Center, Hankyong National University, Anseong-si 17579, South Korea.
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Burns J, McCoy CP, Irwin NJ. Synergistic activity of weak organic acids against uropathogens. J Hosp Infect 2021; 111:78-88. [PMID: 33545217 DOI: 10.1016/j.jhin.2021.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND Urinary tract infections (UTIs) are among the most common hospital-acquired infections, with an estimated 75% of UTIs caused by urinary catheters. In addition to the significant healthcare costs and patient morbidity, the escalating antimicrobial resistance reported among common uropathogens make the investigation of efficacious new antimicrobial strategies of urgent importance. AIM To examine the antibacterial activity of a suite of weak organic acids (WOAs) (citric acid, malic acid, propionic acid, mandelic acid, lactic acid, benzoic acid, pyruvic acid and hippuric acid), alone and in combination, against common nosocomial uropathogens (Proteus mirabilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa). METHODS Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm eradication concentration (MBEC), fractional inhibitory concentration index (FICI) values and kinetics of bactericidal activity of WOAs were determined by microdilution and time-kill assays. FINDINGS All tested WOAs displayed bactericidal activities against uropathogens in their planktonic and biofilm modes of growth when used individually. Moreover, WOAs in combination displayed synergistic activity against P. mirabilis, S. aureus and E. coli, with reductions in MIC values of up to 250-fold and significant reductions in biofilm formation. CONCLUSION The synergistic multi-mechanistic combinations identified herein are anticipated to play an important role in the treatment and prevention of catheter-associated UTIs.
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Affiliation(s)
- J Burns
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - C P McCoy
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - N J Irwin
- School of Pharmacy, Queen's University Belfast, Belfast, Northern Ireland, UK.
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Kang JW, Lee HY, Kang DH. Synergistic bactericidal effect of hot water with citric acid against Escherichia coli O157:H7 biofilm formed on stainless steel. Food Microbiol 2020; 95:103676. [PMID: 33397610 DOI: 10.1016/j.fm.2020.103676] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 11/16/2022]
Abstract
This study investigated the antimicrobial effect of hot water with citric acid against Escherichia coli O157:H7 biofilm on stainless steel (SS). Hot water (50, 60, or 70 °C) with 2% citric acid exhibited a synergistic bactericidal effect on the pathogen biofilm. It was revealed that hot water and citric acid combination induced sub-lethally injured cells. Additionally, mechanisms of the synergistic bactericidal effects of hot water with citric acid were identified through several approaches. In terms of biofilm matrix, hot water removes exopolysaccharides, a major component of extracellular polymeric substances (EPS), thereby increasing contact between surface cells and citric acid, resulting in a synergistic bactericidal effect. In terms of the cell itself, increased permeability of citric acid through cell membranes destructed by hot water promotes the inactivation of superoxide dismutase (SOD) in E. coli O157:H7, which induce synergistic generation of reactive oxygen species (ROS) which promote inactivation of cell by activating lipid peroxidation, resulting in destruction of the cell membrane. Therefore, it is interpreted that when hot water with citric acid is applied to E. coli O157:H7 biofilm, synergy effects on the biofilm matrix and cell itself have a complex interaction with each other, thus causing a dramatic synergistic bactericidal effect.
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Affiliation(s)
- Jun-Won Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea
| | - Hae-Yeon Lee
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 25354, Republic of Korea.
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Kang JW, Kim WJ, Kang DH. Synergistic effect of 222-nm krypton-chlorine excilamp and mild heating combined treatment on inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. Int J Food Microbiol 2020; 329:108665. [PMID: 32497789 DOI: 10.1016/j.ijfoodmicro.2020.108665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/20/2020] [Accepted: 05/16/2020] [Indexed: 10/24/2022]
Abstract
Simultaneous treatment with 222-nm KrCl excilamp and mild heating (EX-MH) at 45, 50 and 55 °C showed synergistic bactericidal effects on non-acid and acid adapted cells of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. In particular, acid-adapted pathogens exhibited increased resistance to EX-MH compared to pathogenic bacteria that were not acid-adapted. Also, elucidation of the synergistic bactericidal mechanism of EX-MH was performed through several assays and this mechanism was described as follows: (i) when KrCl excilamp (EX) and mild heating (MH) are applied simultaneously, MH reversibly inactivates the antioxidant enzyme, superoxide dismutase (SOD), thereby increasing accumulation of reactive oxygen species (ROS) generated by EX and thus inducing synergistic ROS generation, (ii) ROS production induces lipid peroxidation occurrence in the cell membrane, (iii) this lipid peroxidation occurrence in the cell membrane induces synergistic destruction of cell membrane, resulting in synergistic cell death. While EX-MH of 45, 50, or 55 °C reduced E. coli O157:H7 (the pathogen most resistant to EX-MH) in apple juice by 5-log, the qualities such as color (L*, a*, and b*), total phenolic compounds (TPC), and DPPH free radical scavenging activity of apple juice did not change significantly (P > 0.05). This study not only suggests the applicability of EX-MH to the apple juice industry, but also can be used as baseline data for future relevant research.
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Affiliation(s)
- Jun-Won Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Woo-Ju Kim
- Department of Food Science and Technology, The Ohio State University, 2015 Fyffe road, Columbus, OH 43210, USA
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea.
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Foglia C, Allesina S, Amoruso A, De Prisco A, Pane M. New insights in enumeration methodologies of probiotic cells in finished products. J Microbiol Methods 2020; 175:105993. [DOI: 10.1016/j.mimet.2020.105993] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 01/22/2023]
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Guliy OI, Zaitsev BD, Burygin GL, Karavaeva OA, Fomin AS, Staroverov SA, Borodina IA. Prospects for the Use of Gold Nanoparticles to Increase the Sensitivity of an Acoustic Sensor in the Detection of Microbial Cells. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:1727-1737. [PMID: 32376190 DOI: 10.1016/j.ultrasmedbio.2020.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 03/09/2020] [Accepted: 03/18/2020] [Indexed: 06/11/2023]
Abstract
The interaction of microbial cells with antibody-gold nanoparticle conjugates in conductive suspensions was experimentally studied by using an acoustic slot-mode sensor. The sensor consisted of a piezoelectric plate with a propagating acoustic wave and a liquid container located above this plate with a given gap. An analysis of the measured parameters of the sensor revealed that the specific interaction of bacterial cells with the conjugates led to a stronger change in the sensor output signal than the specific interaction of bacterial cells with antibodies. The measurements were made for Azospirillum brasilense Sp7 cells in buffer with an initial conductivity of 5-30 μS/cm. The limit of cell detection with the conjugates was 103 cells/mL, and the analysis took about 4 min. The advantage of the sensor is the possibility of repeated use and cleaning of the liquid container without damaging the sensor's elements. These results are promising for use in rapid test systems for the direct detection of microbial cells in actual samples of liquids in medical diagnostics.
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Affiliation(s)
- Olga I Guliy
- Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, Russia.
| | - Boris D Zaitsev
- Kotel'nikov Institute of Radio Engineering and Electronics, RAS, Saratov Branch, Saratov, Russia
| | - Gennady L Burygin
- Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, Russia
| | - Olga A Karavaeva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, Russia
| | - Alexander S Fomin
- Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, Russia
| | - Sergey A Staroverov
- Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, Russia
| | - Irina A Borodina
- Kotel'nikov Institute of Radio Engineering and Electronics, RAS, Saratov Branch, Saratov, Russia
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Rozloznik M, Lochmanova A, Chmelar D, Hajek M, Korytkova K, Cisarikova M. Experimental use of flow cytometry to detect bacteria viability after hyperbaric oxygen exposure: Work in progress report. Diving Hyperb Med 2020; 50:152-156. [PMID: 32557417 PMCID: PMC7481111 DOI: 10.28920/dhm50.2.152-156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 02/23/2020] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Hyperbaric oxygen treatment (HBOT), based on inhaling pure oxygen under elevated ambient pressure, is used as adjuvant intervention to promote healing in infected wounds. Despite extensive clinical evidence of beneficial effects of HBOT in soft tissue infections the mechanism of action remains to be elucidated. The aim of this study was to evaluate the use of flow cytometry as a novel method to assess the viability of pathogenic bacteria after hyperbaric oxygen (HBO) exposure. METHODS Bacterial strains associated with soft tissues infections: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus were exposed to oxygen at 2.8 atmospheres absolute (atm abs) (283.6 kPa) pressure for 45, 90, or 120 min, then stained with propidium iodide and thiazole orange and analysed by flow cytometry. RESULTS Escherichia coli and Staphylococcus aureus showed no change in viability, nor morphology, the viability of Pseudomonas aeruginosa reduced in a dose-dependent manner and Klebsiella pneumoniae also showed dye uptake after HBO. CONCLUSIONS These initial results, indicate diverse sensitivity of bacteria to HBO, and suggest that flow cytometry can be used to monitor viability and morphological changes triggered by HBO exposure in bacteria.
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Affiliation(s)
- Miroslav Rozloznik
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
- DAN Europe, Slovensko, Slovakia
- DNB consult, s.r.o, Kezmarok, Slovakia
- Corresponding author: Dr Miroslav Rozloznik, Department of Biomedical Sciences, Medical Faculty, University of Ostrava, Syllabova 19, Ostrava, Czech Republic,
| | - Alexandra Lochmanova
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
- Public Health Institute, Ostrava, Czech Republic
| | - Dittmar Chmelar
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
- Czech National Anaerobic Bacteria Reference Laboratory, Faculty of Medicine, University of Ostrava, Czech Republic
| | - Michal Hajek
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
- Centre for Hyperbaric Medicine, City Hospital, Ostrava, Czech Republic
| | - Karin Korytkova
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
| | - Monika Cisarikova
- Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Czech Republic
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Kang JW, Hong HN, Kang DH. Application of a Krypton-Chlorine Excilamp To Control Alicyclobacillus acidoterrestris Spores in Apple Juice and Identification of Its Sporicidal Mechanism. Appl Environ Microbiol 2020; 86:e00159-20. [PMID: 32220842 PMCID: PMC7237776 DOI: 10.1128/aem.00159-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/23/2020] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to investigate the sporicidal effect of a krypton-chlorine (KrCl) excilamp against Alicyclobacillus acidoterrestris spores and to compare its inactivation mechanism to that of a conventional UV lamp containing mercury (Hg). The inactivation effect of the KrCl excilamp was not significantly different from that of the Hg UV lamp for A. acidoterrestris spores in apple juice despite the 222-nm wavelength of the KrCl excilamp having a higher absorption coefficient in apple juice than the 254-nm wavelength of the Hg UV lamp; this is because KrCl excilamps have a fundamentally greater inactivation effect than Hg UV lamps, which is confirmed under ideal conditions (phosphate-buffered saline). The inactivation mechanism analysis revealed that the DNA damage induced by the KrCl excilamp was not significantly different (P > 0.05) from that induced by the Hg UV lamp, while the KrCl excilamp caused significantly higher (P < 0.05) lipid peroxidation incidence and permeability change in the inner membrane of A. acidoterrestris spores than did the Hg UV lamp. Meanwhile, the KrCl excilamp did not generate significant (P > 0.05) intracellular reactive oxygen species, indicating that the KrCl excilamp causes damage only through the direct absorption of UV light. In addition, after KrCl excilamp treatment with a dose of 2,011 mJ/cm2 to reduce A. acidoterrestris spores in apple juice by 5 logs, there were no significant (P > 0.05) changes in quality parameters such as color (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity.IMPORTANCEAlicyclobacillus acidoterrestris spores, which have high resistance to thermal treatment and can germinate even at low pH, are very troublesome in the juice industry. UV technology, a nonthermal treatment, can be an excellent means to control heat-resistant A. acidoterrestris spores in place of thermal treatment. However, the traditionally applied UV sources are lamps that contain mercury (Hg), which is harmful to humans and the environment; thus, there is a need to apply novel UV technology without the use of Hg. In response to this issue, excilamps, an Hg-free UV source, have been actively studied. However, no studies have been conducted applying this technique to control A. acidoterrestris spores. Therefore, the results of this study, which applied a KrCl excilamp for the control of A. acidoterrestris spores and elucidated the inactivation principle, are expected to be utilized as important basic data for application to actual industry or conducting further studies.
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Affiliation(s)
- Jun-Won Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hak-Nyeong Hong
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, Republic of Korea
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Ni J, Hatori S, Wang Y, Li YY, Kubota K. Uncovering Viable Microbiome in Anaerobic Sludge Digesters by Propidium Monoazide (PMA)-PCR. MICROBIAL ECOLOGY 2020; 79:925-932. [PMID: 31701171 DOI: 10.1007/s00248-019-01449-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Use of anaerobic sludge digester is a common practice around the world for solids digestion and methane generation from municipal sewage sludge. Understanding microbial community structure is vital to get better insight into the anaerobic digestion process and to gain better process control. However, selective analysis of viable microorganisms is limited by DNA-based assays. In this study, propidium monoazide (PMA)-PCR with 16S rRNA gene sequencing analysis was used to distinguish live and dead microorganisms based on cell membrane integrity. Microbial community structures of PMA-treated and PMA-untreated anaerobic digester sludge samples were compared. Quantitative PCR revealed that 5-30% of the rRNA genes were derived from inactive or dead cells in anaerobic sludge digesters. This caused a significant decrease in the numbers of operational taxonomic units and Chao1 and Shannon indices compared with that of the PMA-untreated sludge. Microbial community analysis showed that majority of the viable microbiome consisted of Euryarchaeota, Bacteroidetes, Deltaproteobacteria, Chloroflexi, Firmicutes, WWE1, Spirochaetes, Synergistetes, and Caldiserica. On the other hand, after the PMA treatment, numbers of Alphaproteobacteria and Betaproteobacteria declined. These were considered residual microbial members. The network analysis also revealed a relationship among the OTUs belonging to WWE1 and Bacteroidales. PMA-PCR-based 16S rRNA gene sequencing analysis is an effective tool for uncovering viable microbiome in complex environmental samples.
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Affiliation(s)
- Jialing Ni
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Shingo Hatori
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Yin Wang
- Institute of Urban Environment, Chinese Academy of Sciences, 1799 JiMei Road, Xiamen, 361021, China
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Kengo Kubota
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
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Reversibility of membrane permeabilization upon pulsed electric field treatment in Lactobacillus plantarum WCFS1. Sci Rep 2019; 9:19990. [PMID: 31882651 PMCID: PMC6934533 DOI: 10.1038/s41598-019-56299-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/05/2019] [Indexed: 01/31/2023] Open
Abstract
Pulsed electric field (PEF) treatment, or electroporation, can be used to load molecules into cells. The permeabilizing effect of the PEF treatment on the cellular membrane can be either reversible or irreversible depending on the severity of the PEF treatment conditions. The influence of PEF on the reversibility of membrane permeabilization in Lactobacillus plantarum WCFS1 by two different fluorescent staining methods was investigated in this study. Whereas staining with propidium iodide (PI) before and after PEF treatment indicated small reversible permeabilized fractions of maximum 14%, the use of a double staining method with PI and SYTOX Green suggested larger reversible permeabilized fractions up to 40% of the population. This difference shows that the choice for a fluorescent staining method affects the conclusions drawn regarding reversibility of membrane permeabilization. Additionally, the effect of PEF treatment conditions on membrane integrity was compared, indicating a relation between critical electric field strength, cell size and membrane permeabilization. Overall this study showed the possibilities and limitations of fluorescent membrane integrity staining methods for PEF studies.
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Jeon MJ, Ha JW. Inactivating foodborne pathogens in apple juice by combined treatment with fumaric acid and ultraviolet-A light, and mechanisms of their synergistic bactericidal action. Food Microbiol 2019; 87:103387. [PMID: 31948628 DOI: 10.1016/j.fm.2019.103387] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/11/2019] [Accepted: 11/20/2019] [Indexed: 11/26/2022]
Abstract
We evaluated the bactericidal efficacy of the simultaneous application of ultraviolet-A (UV-A) irradiation and fumaric acid (FA) against Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in apple juice and as well as investigated the effects of this treatment on product quality. Further, we elucidated the mechanisms underlying their synergistic bactericidal action. Simultaneous UV-A light irradiation and 0.1% FA treatment for 30 min resulted in 6.65-, 6.27-, and 6.49-log CFU/ml reductions in E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, which involved 3.15, 2.21, and 3.43 log CFU reductions, respectively, and these were attributed to the synergistic action of the combined treatments. Mechanistic investigations suggested that the combined UVA-FA treatment resulted in significantly greater bacterial cell membrane damage and intracellular reactive oxygen species (ROS) generation. UVA-FA treatment for 30 min did not cause significant changes to the color, nonenzymatic browning index, pH, and total phenolic content of apple juice. These results suggest that combined UVA-FA treatment can be effectively used to control foodborne pathogens in apple juice without affecting its quality.
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Affiliation(s)
- Min-Jin Jeon
- Department of Food Science and Biotechnology, College of Engineering, Food & Bio-industry Research Center, Hankyong National University, Anseong-si, 17579, South Korea
| | - Jae-Won Ha
- Department of Food Science and Biotechnology, College of Engineering, Food & Bio-industry Research Center, Hankyong National University, Anseong-si, 17579, South Korea.
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45
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van Tatenhove-Pel RJ, Zwering E, Solopova A, Kuipers OP, Bachmann H. Ampicillin-treated Lactococcus lactis MG1363 populations contain persisters as well as viable but non-culturable cells. Sci Rep 2019; 9:9867. [PMID: 31285492 PMCID: PMC6614399 DOI: 10.1038/s41598-019-46344-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/23/2019] [Indexed: 12/12/2022] Open
Abstract
Lactococcus lactis is used as cell-factory and strain selections are regularly performed to improve production processes. When selection regimes only allow desired phenotypes to survive, for instance by using antibiotics to select for cells that do not grow in a specific condition, the presence of more resistant subpopulations with a wildtype genotype severely slows down the procedure. While the food grade organism L. lactis is not often exposed to antibiotics we characterized its response to ampicillin in more detail, to better understand emerging population heterogeneity and how this might affect strain selection procedures. Using growth-dependent viability assays we identified persister subpopulations in stationary and exponential phase. Growth-independent viability assays revealed a 100 times larger subpopulation that did not grow on plates or in liquid medium, but had an intact membrane and could maintain a pH gradient. Over one third of these cells restored their intracellular pH when we induced a temporary collapse, indicating that this subpopulation was metabolically active and in a viable but non-culturable state. Exposure of L. lactis MG1363 to ampicillin therefore results in a heterogeneous population response with different dormancy states. These dormant cells should be considered in survival-based strain selection procedures.
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Affiliation(s)
- Rinke J van Tatenhove-Pel
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands
- NIZO Food Research, Kernhemseweg 2, 6718 ZB, Ede, The Netherlands
| | - Emile Zwering
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands
| | - Ana Solopova
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Herwig Bachmann
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands.
- NIZO Food Research, Kernhemseweg 2, 6718 ZB, Ede, The Netherlands.
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Screening sediment samples used as anolytes in microbial fuel cells for microbial electron transfer activity using DREAM assay. Biotechnol Lett 2019; 41:979-985. [DOI: 10.1007/s10529-019-02704-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/21/2019] [Indexed: 10/26/2022]
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47
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Stratford JP, Edwards CLA, Ghanshyam MJ, Malyshev D, Delise MA, Hayashi Y, Asally M. Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity. Proc Natl Acad Sci U S A 2019; 116:9552-9557. [PMID: 31000597 PMCID: PMC6511025 DOI: 10.1073/pnas.1901788116] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Membrane-potential dynamics mediate bacterial electrical signaling at both intra- and intercellular levels. Membrane potential is also central to cellular proliferation. It is unclear whether the cellular response to external electrical stimuli is influenced by the cellular proliferative capacity. A new strategy enabling electrical stimulation of bacteria with simultaneous monitoring of single-cell membrane-potential dynamics would allow bridging this knowledge gap and further extend electrophysiological studies into the field of microbiology. Here we report that an identical electrical stimulus can cause opposite polarization dynamics depending on cellular proliferation capacity. This was demonstrated using two model organisms, namely Bacillus subtilis and Escherichia coli, and by developing an apparatus enabling exogenous electrical stimulation and single-cell time-lapse microscopy. Using this bespoke apparatus, we show that a 2.5-second electrical stimulation causes hyperpolarization in unperturbed cells. Measurements of intracellular K+ and the deletion of the K+ channel suggested that the hyperpolarization response is caused by the K+ efflux through the channel. When cells are preexposed to 400 ± 8 nm wavelength light, the same electrical stimulation depolarizes cells instead of causing hyperpolarization. A mathematical model extended from the FitzHugh-Nagumo neuron model suggested that the opposite response dynamics are due to the shift in resting membrane potential. As predicted by the model, electrical stimulation only induced depolarization when cells are treated with antibiotics, protonophore, or alcohol. Therefore, electrically induced membrane-potential dynamics offer a reliable approach for rapid detection of proliferative bacteria and determination of their sensitivity to antimicrobial agents at the single-cell level.
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Affiliation(s)
- James P Stratford
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, West Midlands, CV4 7AL,United Kingdom
| | - Conor L A Edwards
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Manjari J Ghanshyam
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Dmitry Malyshev
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Marco A Delise
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
| | - Yoshikatsu Hayashi
- Department of Biomedical Engineering, School of Biological Sciences, University of Reading, Reading, Berkshire, RG6 6AH, United Kingdom
| | - Munehiro Asally
- School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom;
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, West Midlands, CV4 7AL,United Kingdom
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom
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Jackson SA, Schoeni JL, Vegge C, Pane M, Stahl B, Bradley M, Goldman VS, Burguière P, Atwater JB, Sanders ME. Improving End-User Trust in the Quality of Commercial Probiotic Products. Front Microbiol 2019; 10:739. [PMID: 31105649 PMCID: PMC6499161 DOI: 10.3389/fmicb.2019.00739] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/25/2019] [Indexed: 01/09/2023] Open
Abstract
In a rapidly growing global probiotic market, end-users have difficulty distinguishing between high quality and poor quality products. This ambiguity threatens the trust consumers and healthcare providers have in probiotic products. To address this problem, we recommend that companies undergo third-party evaluations to certify probiotic quality and label accuracy. In order to communicate about product quality to end-users, indication of certification on product labels is helpful, although not all manufacturers choose to use this approach. Herein we discuss: third-party certification, the process of setting standards for identity, purity, and quantification of probiotics; some emerging methodologies useful for quality assessment; and some technical challenges unique to managing quality of live microbial products. This review provides insights of an Expert Panel engaged in this process and aims to update the reader on relevant current scientific methodologies. Establishing validated methodologies for all aspects of quality assessment is an essential component of this process and can be facilitated by established organizations, such as United States Pharmacopeia. Emerging methodologies including whole genome sequencing and flow cytometry are poised to play important roles in these processes.
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Affiliation(s)
- Scott A. Jackson
- National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Jean L. Schoeni
- Eurofins Food Integrity and Innovation, Madison, WI, United States
| | | | | | - Buffy Stahl
- DuPont Nutrition & Health, Madison, WI, United States
| | | | - Virginia S. Goldman
- Department of Dietary Supplements and Herbal Medicines, Science Division, US Pharmacopeial Convention, Rockville, MD, United States
| | | | | | - Mary Ellen Sanders
- International Scientific Association for Probiotics and Prebiotics, Sacramento, CA, United States
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Kang JW, Kang DH. Increased Resistance of Salmonella enterica Serovar Typhimurium and Escherichia coli O157:H7 to 222-Nanometer Krypton-Chlorine Excilamp Treatment by Acid Adaptation. Appl Environ Microbiol 2019; 85:e02221-18. [PMID: 30610077 PMCID: PMC6414383 DOI: 10.1128/aem.02221-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 12/24/2018] [Indexed: 11/20/2022] Open
Abstract
In this study, we examined the change in resistance of Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 to 222-nm krypton-chlorine (KrCl) excilamp treatment as influenced by acid adaptation and identified a mechanism of resistance change. In addition, we measured changes in apple juice quality indicators, such as color, total phenols, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, during treatment. Non-acid-adapted and acid-adapted pathogens were induced by growing the cells in tryptic soy broth without dextrose (TSB w/o D) at pH 7.3 and in TSB w/o D at pH 5.0 (adjusted with HCl), respectively. For the KrCl excilamp treatment, acid-adapted pathogens exhibited significantly (P < 0.05) higher D5d values, which indicate dosages required to achieve a 5-log reduction, than those for non-acid-adapted pathogens in both commercially clarified apple juice and phosphate-buffered saline (PBS), and the pathogens in the juice showed significantly (P < 0.05) higher D5d values than those for pathogens in PBS because of the UV-absorbing characteristics of apple juice. Through mechanism identification, it was found that the generation of lipid peroxidation in the cell membrane, inducing cell membrane destruction, was significantly (P < 0.05) lower in acid-adapted cells than in non-acid-adapted cells for the same amount of reactive oxygen species (ROS) generated at the same dose because the ratio of unsaturated to saturated fatty acids (USFA/SFA) in the cell membrane was significantly (P < 0.05) decreased as a result of acid adaptation. Treated apple juice showed no significant (P > 0.05) difference in quality indicators compared to those of untreated controls during treatment at 1,773 mJ/cm2IMPORTANCE There is a need for novel, mercury-free UV lamp technology to replace germicidal lamps containing harmful mercury, which are routinely utilized for UV pasteurization of apple juice. In addition, consideration of the changes in response to antimicrobial treatments that may occur when pathogens are adapted to the acid in an apple juice matrix is critical to the practical application of this technology. Based on this, an investigation using 222-nm KrCl excilamp technology, an attractive alternative to mercury lamps, was conducted. Our study demonstrated increased resistance to 222-nm KrCl excilamp treatment as pathogens adapted to acids, and this was due to changes in reactivity to ROS with changes in the fatty acid composition of the cell membrane. Despite increased resistance, the 222-nm KrCl excilamp achieved pathogen reductions of 5 log or more at laboratory scale without affecting apple juice quality. These results provide valuable baseline data for application of 222-nm KrCl excilamps in the apple juice industry.
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Affiliation(s)
- Jun-Won Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Institutes of Green-bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, Republic of Korea
| | - Dong-Hyun Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Institutes of Green-bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, Republic of Korea
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50
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Aiyer KS, Rai R, Vijayakumar BS. Assessing Activity of Antimicrobial Agents and Screening Antibiotic-Resistant Bacteria Through DREAM Assay. Appl Biochem Biotechnol 2019; 188:1158-1167. [DOI: 10.1007/s12010-019-02981-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/20/2019] [Indexed: 11/25/2022]
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