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Gongora K, Vankerschaver J, Sampers I, Van Haute S. The influence of pH on the efficacy of oxidation-reduction potential (ORP) to predict chlorine disinfection of surrogate bacteria, Escherichia coli O157:H7 and Listeria monocytogenes in oxidant demand free conditions and fresh produce wash water. Food Microbiol 2024; 121:104516. [PMID: 38637078 DOI: 10.1016/j.fm.2024.104516] [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: 11/23/2023] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/20/2024]
Abstract
Oxidation-reduction potential (ORP) is commonly used as a rapid measurement of the antimicrobial potential of free chlorine during industrial fresh produce washing. The current study tested the hypothesis that ORP can act as a "single variable" measurement of bacterial (vegetative and endospores) inactivation effectiveness with free chlorine irrespective of the water pH value. This situation has on occasion been assumed but never confirmed nor disproven. Chlorine-dosed pH 6.5 and 8.5 phosphate buffer solutions were inoculated with Escherichia coli (E. coli), Listeria innocua (L. innocua), or Bacillus subtilis (B. subtilis) endospores. ORP, free chlorine (FC), and log reduction were monitored after 5 s (for E. coli and L. innocua) and up to 30 min (for B. subtilis spores) of disinfection. Logistic and exponential models were developed to describe how bacteria reduction varied as a function of ORP at different pH levels. Validation tests were performed in phosphate buffered pH 6.5 and 8.5 cabbage wash water periodically dosed with FC, cabbage extract and a cocktail of Escherichia coli O157:H7 (E. coli O157:H7) and Listeria monocytogenes (L. monocytogenes). The built logistic and exponential models confirmed that at equal ORP values, the inactivation of the surrogate strains was not consistent across pH 6.5 and pH 8.5, with higher reductions at higher pH. This is the opposite of the well-known free chlorine-controlled bacterial inactivation, where the antibacterial effect is higher at lower pH. The validation test results indicated that in the cabbage wash water, the relationship between disinfection efficiency and ORP was consistent with the oxidant demand free systems. The study suggests that ORP cannot serve as a reliable single variable measurement to predict bacterial disinfection in buffered systems. When using ORP to monitor and control the antibacterial effectiveness of the chlorinated wash water, it is crucial to take into account (and control) the pH.
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Affiliation(s)
- Kimberly Gongora
- Laboratory of Food Microbiology and Biotechnology, Department of Food Technology, Safety and Health, Ghent University, 9000, Ghent, Belgium; Center for Food Biotechnology and Microbiology, Ghent University Global Campus, Incheon, 21985, South Korea
| | - Joris Vankerschaver
- Center for Biosystems and Biotech Data Science, Ghent University Global Campus, Incheon, 21985, South Korea; Department of Applied Mathematics, Computer Science and Statistics, Ghent University, 9000, Ghent, Belgium
| | - Imca Sampers
- Laboratory of Food Microbiology and Biotechnology, Department of Food Technology, Safety and Health, Ghent University, 9000, Ghent, Belgium; Research Unit VEG-i-TEC, Department of Food Technology, Safety and Health, Ghent University, Campus Kortrijk, Sint-Martens-Latemlaan 2B, 8500, Kortrijk, Belgium
| | - Sam Van Haute
- Laboratory of Food Microbiology and Biotechnology, Department of Food Technology, Safety and Health, Ghent University, 9000, Ghent, Belgium; Center for Food Biotechnology and Microbiology, Ghent University Global Campus, Incheon, 21985, South Korea.
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2
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Yang W, Yuan Y, He L, Fan H. Single-cell analysis reveals microbial spore responses to sodium hypochlorite. JOURNAL OF BIOPHOTONICS 2024; 17:e202400015. [PMID: 38613161 DOI: 10.1002/jbio.202400015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/30/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
Pollution from toxic spores has caused us a lot of problems because spores are extremely resistant and can survive most disinfectants. Therefore, the detection of spore response to disinfectant is of great significance for the development of effective decontamination strategies. In this work, we investigated the effect of 0.5% sodium hypochlorite on the molecular and morphological properties of single spores of Bacillus subtilis using single-cell techniques. Laser tweezers Raman spectroscopy showed that sodium hypochlorite resulted in Ca2+-dipicolinic acid release and nucleic acid denaturation. Atomic force microscopy showed that the surface of treated spores changed from rough to smooth, protein shells were degraded at 10 min, and the permeability barrier was destroyed at 15 min. The spore volume decreased gradually over time. Live-cell imaging showed that the germination and growth rates decreased with increasing treatment time. These results provide new insight into the response of spores to sodium hypochlorite.
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Affiliation(s)
- Weiming Yang
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong, China
| | - Yufeng Yuan
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
| | - Lin He
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
| | - Haihua Fan
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong, China
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3
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Malyshev D, Lee CC, Andersson M. Evaluating Bacterial Spore Preparation Methods for Scanning Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024:ozae037. [PMID: 38701197 DOI: 10.1093/mam/ozae037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/07/2024] [Accepted: 03/31/2024] [Indexed: 05/05/2024]
Abstract
Scanning electron microscopy (SEM) can reveal the ultrastructure of bacterial spores, including morphology, surface features, texture, spore damage, germination, and appendages. Understanding these features can provide a basis for adherence, how physical and environmental stressors affect spore viability, integrity, and functionality, as well as the distribution and function of surface appendages. However, the spore sample preparation method can significantly impact the SEM images' appearance, resolution, and overall quality. In this study, we compare different spore preparation methods to identify optimal approaches for preparation time, spore appearance and resolved features, including the exosporium and spore pili, for SEM imaging. We use Bacillus paranthracis as model species and evaluate the efficacy of preparation protocols using different fixation and drying methods, as well as imaging under room- and cryogenic temperatures. We compare and assess method complexity to the visibility of the spore exosporium and spore appendages across different methods. Additionally, we use Haralick texture features to quantify the differences in spore surface appearance and determine the most suitable method for preserving spore structures and surface features during SEM evaluation. The findings from this study will help establish protocols for preparing bacterial spores for SEM and facilitating accurate and reliable analysis of spores' characteristics.
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Affiliation(s)
- Dmitry Malyshev
- Department of Physics, Umeå University, Linnaeus Väg, Umeå 901 87, Sweden
| | - Cheng Choo Lee
- Umeå Centre for Electron Microscopy (UCEM), Umeå University, Linnaeus Väg, Umeå 901 87, Sweden
| | - Magnus Andersson
- Department of Physics, Umeå University, Linnaeus Väg, Umeå 901 87, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Linnaeus Väg, Umeå 901 87, Sweden
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4
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Öberg R, Sil TB, Ohlin A, Andersson M, Malyshev D. Assessing CaDPA levels, metabolic activity, and spore detection through deuterium labeling. Analyst 2024; 149:1861-1871. [PMID: 38348676 DOI: 10.1039/d3an02162a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Many strains among spore-forming bacteria species are associated with food spoilage, foodborne disease, and hospital-acquired infections. Understanding the impact of environmental conditions and decontamination techniques on the metabolic activity, viability, and biomarkers of these spores is crucial for combatting them. To distinguish and track spores and to understand metabolic mechanisms, spores must be labeled. Staining or genetic modification are current methods for this, however, these methods can be time-consuming, and affect the viability and function of spore samples. In this work, we investigate the use of heavy water for permanent isotope labeling of spores and Raman spectroscopy for tracking sporulation/germination mechanisms. We also discuss the potential of this method in observing decontamination. We find that steady-state deuterium levels in the spore are achieved after only ∼48 h of incubation with 30% D2O-infused broth and sporulation, generating Raman peaks at cell silent region of 2200 and 2300 cm-1. These deuterium levels then decrease rapidly upon spore germination in non-deuterated media. We further find that unlike live spores, spores inactivated using various methods do not lose these Raman peaks upon incubation in growth media, suggesting these peaks may be used to indicate the viability of a spore sample. We further observe several Raman peaks exclusive to deuterated DPA, a spore-specific chemical biomarker, at e.g. 988 and 2300 cm-1, which can be used to track underlying changes in spores involving DPA. In conclusion, permanent spore labeling using deuterium offers a robust and non-invasive way of labeling bacterial spores for marking, viability determination, and characterising spore activity.
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Affiliation(s)
- Rasmus Öberg
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
- Swedish Defence Research Agency (FOI), Cementvägen 20, 906 21 Umeå, Sweden
| | - Timir Baran Sil
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
| | - André Ohlin
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | | | - Dmitry Malyshev
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
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5
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Öberg R, Sil TB, Johansson AC, Malyshev D, Landström L, Johansson S, Andersson M, Andersson PO. UV-Induced Spectral and Morphological Changes in Bacterial Spores for Inactivation Assessment. J Phys Chem B 2024; 128:1638-1646. [PMID: 38326108 PMCID: PMC10895659 DOI: 10.1021/acs.jpcb.3c07062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
The ability to detect and inactivate spore-forming bacteria is of significance within, for example, industrial, healthcare, and defense sectors. Not only are stringent protocols necessary for the inactivation of spores but robust procedures are also required to detect viable spores after an inactivation assay to evaluate the procedure's success. UV radiation is a standard procedure to inactivate spores. However, there is limited understanding regarding its impact on spores' spectral and morphological characteristics. A further insight into these UV-induced changes can significantly improve the design of spore decontamination procedures and verification assays. This work investigates the spectral and morphological changes to Bacillus thuringiensis spores after UV exposure. Using absorbance and fluorescence spectroscopy, we observe an exponential decay in the spectral intensity of amino acids and protein structures, as well as a logistic increase in dimerized DPA with increased UV exposure on bulk spore suspensions. Additionally, using micro-Raman spectroscopy, we observe DPA release and protein degradation with increased UV exposure. More specifically, the protein backbone's 1600-1700 cm-1 amide I band decays slower than other amino acid-based structures. Last, using electron microscopy and light scattering measurements, we observe shriveling of the spore bodies with increased UV radiation, alongside the leaking of core content and disruption of proteinaceous coat and exosporium layers. Overall, this work utilized spectroscopy and electron microscopy techniques to gain new understanding of UV-induced spore inactivation relating to spore degradation and CaDPA release. The study also identified spectroscopic indicators that can be used to determine spore viability after inactivation. These findings have practical applications in the development of new spore decontamination and inactivation validation methods.
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Affiliation(s)
- Rasmus Öberg
- Swedish
Defence Research Agency (FOI), Umeå 90621, Sweden
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | - Timir B. Sil
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | | | | | - Lars Landström
- Swedish
Defence Research Agency (FOI), Norra Sorunda 13794, Sweden
| | | | - Magnus Andersson
- Department
of Physics, Umeå University, Umeå 90736, Sweden
- Umeå
Centre for Microbial Research (UCMR), Umeå 90736, Sweden
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Lin Y, He Y, Sun Q, Ping Q, Huang M, Wang L, Li Y. Underlying the mechanisms of pathogen inactivation and regrowth in wastewater using peracetic acid-based disinfection processes: A critical review. JOURNAL OF HAZARDOUS MATERIALS 2024; 463:132868. [PMID: 37944231 DOI: 10.1016/j.jhazmat.2023.132868] [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: 08/27/2023] [Revised: 10/17/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023]
Abstract
Peracetic acid (PAA) disinfection is an emerging wastewater disinfection process. Its advantages include excellent pathogen inactivation performance and little generation of toxic and harmful disinfection byproducts. The objective of this review is to comprehensively analyze the experimental data and scientific information related to PAA-based disinfection processes. Kinetic models and modeling frameworks are discussed to provide effective tools to assess pathogen inactivation efficacy. Then, the efficacy of PAA-based disinfection processes for pathogen inactivation is summarized, and the inactivation mechanisms involved in disinfection and the interactions of PAA with conventional disinfection processes are elaborated. Subsequently, the risk of pathogen regrowth after PAA-based disinfection process is clearly discussed. Finally, to address ecological risks related to PAA-based disinfection, its impact on the spread of antibiotic-resistant bacteria and the transfer of antibiotic resistance genes (ARGs) is also assessed. Among advanced PAA-based disinfection processes, ultraviolet/PAA is promising not only because it has practical application value but also because pathogen regrowth can be inhibited and ARGs transfer risk can be significantly reduced via this process. This review presents valuable and comprehensive information to provide an in-depth understanding of PAA as an alternative wastewater disinfection technology.
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Affiliation(s)
- Yuqian Lin
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Yunpeng He
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Qiya Sun
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Qian Ping
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China
| | - Manhong Huang
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China; Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, People's Republic of China
| | - Lin Wang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China.
| | - Yongmei Li
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China
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7
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Wu-Chen RA, Feng J, Elhadidy M, Nambiar RB, Liao X, Yue M, Ding T. Long-term exposure to food-grade disinfectants causes cross-resistance to antibiotics in Salmonella enterica serovar Typhimurium strains with different antibiograms and sequence types. Antimicrob Resist Infect Control 2023; 12:145. [PMID: 38093321 PMCID: PMC10717106 DOI: 10.1186/s13756-023-01333-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 11/09/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Disinfectants are important in the food industry to prevent the transmission of pathogens. Excessive use of disinfectants may increase the probability of bacteria experiencing long-term exposure and consequently resistance and cross-resistance to antibiotics. This study aims to investigate the cross-resistance of multidrug-resistant, drug-resistant, and drug-susceptible isolates of Salmonella enterica serovar Typhimurium (S. Typhimurium) with different sequence types (STs) to a group of antibiotics after exposure to different food-grade disinfectants. METHODS A panel of 27 S. Typhimurium strains with different antibiograms and STs were exposed to increasing concentrations of five food-grade disinfectants, including hydrogen peroxide (H2O2), benzalkonium chloride (BAC), chlorine dioxide (ClO2), sodium hypochlorite (NaClO), and ethanol. Recovered evolved strains were analyzed using genomic tools and phenotypic tests. Genetic mutations were screened using breseq pipeline and changes in resistance to antibiotics and to the same disinfectant were determined. The relative fitness of evolved strains was also determined. RESULTS Following exposure to disinfectants, 22 out of 135 evolved strains increased their resistance to antibiotics from a group of 14 clinically important antibiotics. The results also showed that 9 out of 135 evolved strains had decreased resistance to some antibiotics. Genetic mutations were found in evolved strains. A total of 77.78% of ST34, 58.33% of ST19, and 66.67% of the other STs strains exhibited changes in antibiotic resistance. BAC was the disinfectant that induced the highest number of strains to cross-resistance to antibiotics. Besides, H2O2 induced the highest number of strains with decreased resistance to antibiotics. CONCLUSIONS These findings provide a basis for understanding the effect of disinfectants on the antibiotic resistance of S. Typhimurium. This work highlights the link between long-term exposure to disinfectants and the evolution of resistance to antibiotics and provides evidence to promote the regulated use of disinfectants.
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Affiliation(s)
- Ricardo A Wu-Chen
- Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Jinsong Feng
- Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Mohamed Elhadidy
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
- Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Reshma B Nambiar
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xinyu Liao
- Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing, 314100, China
| | - Min Yue
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Tian Ding
- Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China.
- Future Food Laboratory, Innovation Center of Yangtze River Delta, Zhejiang University, Jiaxing, 314100, China.
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8
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Qamar S, Öberg R, Malyshev D, Andersson M. A hybrid CNN-Random Forest algorithm for bacterial spore segmentation and classification in TEM images. Sci Rep 2023; 13:18758. [PMID: 37907463 PMCID: PMC10618482 DOI: 10.1038/s41598-023-44212-5] [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: 05/08/2023] [Accepted: 10/05/2023] [Indexed: 11/02/2023] Open
Abstract
We present a new approach to segment and classify bacterial spore layers from Transmission Electron Microscopy (TEM) images using a hybrid Convolutional Neural Network (CNN) and Random Forest (RF) classifier algorithm. This approach utilizes deep learning, with the CNN extracting features from images, and the RF classifier using those features for classification. The proposed model achieved 73% accuracy, 64% precision, 46% sensitivity, and 47% F1-score with test data. Compared to other classifiers such as AdaBoost, XGBoost, and SVM, our proposed model demonstrates greater robustness and higher generalization ability for non-linear segmentation. Our model is also able to identify spores with a damaged core as verified using TEMs of chemically exposed spores. Therefore, the proposed method will be valuable for identifying and characterizing spore features in TEM images, reducing labor-intensive work as well as human bias.
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Affiliation(s)
- Saqib Qamar
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden
| | - Rasmus Öberg
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
| | - Dmitry Malyshev
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
| | - Magnus Andersson
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden.
- Umeå Centre for Microbial Research (UCMR), Umeå, Sweden.
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9
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Bogun K, Peh E, Siekmann L, Plötz M, Kittler S. Combining antimicrobial substances for Campylobacter post harvest mitigation on chicken breast fillet and chicken skin - any synergistic effects? J Appl Microbiol 2023; 134:lxad209. [PMID: 37709568 DOI: 10.1093/jambio/lxad209] [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: 07/10/2023] [Revised: 09/01/2023] [Accepted: 09/12/2023] [Indexed: 09/16/2023]
Abstract
AIMS To reduce Campylobacter along the food chain, we investigated the mitigation potential of four antimicrobial compounds against Campylobacter using a new evaluation scheme. METHODS AND RESULTS Using the checkerboard method, the minimum inhibitory concentration (MIC) values of two organic acids (peroxyacetic acid and lactic acid) and two plant extracts (carvacrol and resveratrol) against a C. jejuni and a C. coli field isolate were determined as well as the fractional inhibitory concentration (FIC) indices of combined treatment. The lowest MIC values were found for peroxyacetic acid (0.03 mg mL-1) and carvacrol (0.06 mg mL-1). Based on subsequent sensory studies, peroxyacetic acid and carvacrol were selected for challenge tests to quantitatively determine the reducing potential against Campylobacter on chicken meat and chicken skin. Applying peroxyacetic acid significantly reduced Campylobacter counts on chicken skin with maximum reductions of 3.3 log-units (P < .0001), while the combination of peroxyacetic acid and carvacrol resulted in significant reductions of only 0.4 log-units on chicken breast fillet 24 hours after treatment but not thereafter (P = .0192). CONCLUSIONS Peroxyacetic acid is suitable as a postharvest intervention measure to reduce Campylobacter concentration on chicken skin without reducing consumer acceptance.
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Affiliation(s)
- Katrin Bogun
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover 30173, Germany
| | - Elisa Peh
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover 30173, Germany
| | - Lisa Siekmann
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover 30173, Germany
| | - Madeleine Plötz
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover 30173, Germany
| | - Sophie Kittler
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover 30173, Germany
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10
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Verguet N, Mondange L, Nolent F, Depeille A, Garnier A, Neulat-Ripoll F, Gorgé O, Tournier JN. Assessment of calcium hypochlorite for Bacillus anthracis spore surface's decontamination. Res Microbiol 2023; 174:104053. [PMID: 36925026 DOI: 10.1016/j.resmic.2023.104053] [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: 12/10/2022] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 03/15/2023]
Abstract
Contamination with microorganisms occurs in laboratories but is also of high concern in the context of bioterrorism. Decontamination is a cornerstone that promotes good laboratory practices and occupational health and safety. Among the most resistant structures formed by microorganisms are spores, produced notably by Clostridium and Bacillus species. Here, we compared six products containing four different molecules (hydrogen peroxide, peracetic acid, sodium and calcium hypochlorite) on B. anthracis Sterne spores. We first selected the most efficient product based on its activity against spore suspensions using French and European standards. Four products showed sporicidal activity, of which only two did so in a time frame consistent with good laboratory practices. Then, we tested one of these two products under laboratory conditions on fully virulent B. anthracis spores, during common use and after contamination through a spill of a highly concentrated spore suspension. We, thus, robustly validated a decontaminant based on calcium hypochlorite not only on its ability to kill spores but also on its effectiveness under laboratory conditions. At the end, we were able to assure a complete disinfection in 1 min after spillover and in 2 min for common use.
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Affiliation(s)
- Noémie Verguet
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; CNR-LE Charbon, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Lou Mondange
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; Yersinia Unit, Institut Pasteur, 75015 Paris, France.
| | - Flora Nolent
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Anne Depeille
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; CNR-LE Charbon, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Annabelle Garnier
- Immunopathology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Fabienne Neulat-Ripoll
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Olivier Gorgé
- Bacteriology Unit, Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; CNR-LE Charbon, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France.
| | - Jean-Nicolas Tournier
- CNR-LE Charbon, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; École du Val-de-Grâce, 75015 Paris, France.
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11
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Nilsson DPG, Jonsmoen UL, Malyshev D, Öberg R, Wiklund K, Andersson M. Physico-chemical characterization of single bacteria and spores using optical tweezers. Res Microbiol 2023; 174:104060. [PMID: 37068697 DOI: 10.1016/j.resmic.2023.104060] [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: 10/21/2022] [Revised: 03/23/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Spore-forming pathogenic bacteria are adapted for adhering to surfaces, and their endospores can tolerate strong chemicals making decontamination difficult. Understanding the physico-chemical properties of bacteria and spores is therefore essential in developing antiadhesive surfaces and disinfection techniques. However, measuring physico-chemical properties in bulk does not show the heterogeneity between cells. Characterizing bacteria on a single-cell level can thereby provide mechanistic clues usually hidden in bulk measurements. This paper shows how optical tweezers can be applied to characterize single bacteria and spores, and how physico-chemical properties related to adhesion, fluid dynamics, biochemistry, and metabolic activity can be assessed.
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Affiliation(s)
| | - Unni Lise Jonsmoen
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Norway.
| | - Dmitry Malyshev
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Rasmus Öberg
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Krister Wiklund
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Magnus Andersson
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden; Umeå Center for Microbial Research (UCMR), 901 87 Sweden.
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12
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Xu M, Selvaraj GK, Lu H. Environmental sporobiota: Occurrence, dissemination, and risks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161809. [PMID: 36702282 DOI: 10.1016/j.scitotenv.2023.161809] [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: 11/22/2022] [Revised: 01/03/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Spore-forming bacteria known as sporobiota are widespread in diverse environments from terrestrial and aquatic habitats to industrial and healthcare systems. Studies on sporobiota have been mainly focused on food processing and clinical fields, while a large amount of sporobiota exist in natural environments. Due to their persistence and capabilities of transmitting virulence factors and antibiotic resistant genes, environmental sporobiota could pose significant health risks to humans. These risks could increase as global warming and environmental pollution has altered the life cycle of sporobiota. This review summarizes the current knowledge of environmental sporobiota, including their occurrence, characteristics, and functions. An interaction network among clinical-, food-related, and environment-related sporobiota is constructed. Recent and effective methods for detecting and disinfecting environmental sporobiota are also discussed. Key problems and future research needs for better understanding and reducing the risks of environmental sporobiota and sporobiome are proposed.
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Affiliation(s)
- Min Xu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ganesh-Kumar Selvaraj
- Department of Microbiology, St. Peter's Institute of Higher Education and Research, Chennai 600054, Tamil Nadu, India.
| | - Huijie Lu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Water Pollution Control and Environmental Safety, Zhejiang, China.
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13
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Malyshev D, Jones IA, McKracken M, Öberg R, Harper GM, Joshi LT, Andersson M. Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes. BMC Microbiol 2023; 23:59. [PMID: 36879193 PMCID: PMC9986864 DOI: 10.1186/s12866-023-02787-z] [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: 10/17/2022] [Accepted: 02/06/2023] [Indexed: 03/08/2023] Open
Abstract
BACKGROUND Clostridioides difficile is a spore forming bacterial species and the major causative agent of nosocomial gastrointestinal infections. C. difficile spores are highly resilient to disinfection methods and to prevent infection, common cleaning protocols use sodium hypochlorite solutions to decontaminate hospital surfaces and equipment. However, there is a balance between minimising the use of harmful chemicals to the environment and patients as well as the need to eliminate spores, which can have varying resistance properties between strains. In this work, we employ TEM imaging and Raman spectroscopy to analyse changes in spore physiology in response to sodium hypochlorite. We characterize different C. difficile clinical isolates and assess the chemical's impact on spores' biochemical composition. Changes in the biochemical composition can, in turn, change spores' vibrational spectroscopic fingerprints, which can impact the possibility of detecting spores in a hospital using Raman based methods. RESULTS We found that the isolates show significantly different susceptibility to hypochlorite, with the R20291 strain, in particular, showing less than 1 log reduction in viability for a 0.5% hypochlorite treatment, far below typically reported values for C. difficile. While TEM and Raman spectra analysis of hypochlorite-treated spores revealed that some hypochlorite-exposed spores remained intact and not distinguishable from controls, most spores showed structural changes. These changes were prominent in B. thuringiensis spores than C. difficile spores. CONCLUSION This study highlights the ability of certain C. difficile spores to survive practical disinfection exposure and the related changes in spore Raman spectra that can be seen after exposure. These findings are important to consider when designing practical disinfection protocols and vibrational-based detection methods to avoid a false-positive response when screening decontaminated areas.
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Affiliation(s)
| | | | | | - Rasmus Öberg
- Department of Physics, Umeå University, Umeå, Sweden
| | | | | | - Magnus Andersson
- Department of Physics, Umeå University, Umeå, Sweden. .,Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.
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14
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Wu RA, Feng J, Yue M, Liu D, Ding T. Overuse of food-grade disinfectants threatens a global spread of antimicrobial-resistant bacteria. Crit Rev Food Sci Nutr 2023:1-10. [PMID: 36756870 DOI: 10.1080/10408398.2023.2176814] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Food-grade disinfectants are extensively used for microbial decontamination of food processing equipment. In recent years, food-grade disinfectants have been increasingly used. However, the overuse of disinfectants causes another major issue, which is the emergence and spread of antimicrobial-resistant bacteria on a global scale. As the ongoing pandemic takes global attention, bacterial infections with antibiotic resistance are another ongoing pandemic that often goes unnoticed and will be the next real threat to humankind. Here, the effects of food-grade disinfectant overuse on the global emergence and spread of antimicrobial-resistant bacteria were reviewed. It was found that longtime exposure to the most common food-grade disinfectants promoted resistance to clinically important antibiotics in pathogenic bacteria, namely cross-resistance. Currently, the use of disinfectants is largely unregulated. The mechanisms of cross-resistance are regulated by intrinsic molecular mechanisms including efflux pumps, DNA repair system, modification of the molecular target, and metabolic adaptation. Cross-resistance can also be acquired by mobile genetic elements. Long-term exposure to disinfectants has an impact on the dissemination of antimicrobial resistance in soil, plants, animals, water, and human gut environments.
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Affiliation(s)
- Ricardo A Wu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Jinsong Feng
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Min Yue
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Donghong Liu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- Ningbo Research Institute, Zhejiang University, Ningbo, China
| | - Tian Ding
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- Ningbo Research Institute, Zhejiang University, Ningbo, China
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15
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Romero-Rodríguez A, Ruiz-Villafán B, Martínez-de la Peña CF, Sánchez S. Targeting the Impossible: A Review of New Strategies against Endospores. Antibiotics (Basel) 2023; 12:antibiotics12020248. [PMID: 36830159 PMCID: PMC9951900 DOI: 10.3390/antibiotics12020248] [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: 12/05/2022] [Revised: 01/13/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
Endospore-forming bacteria are ubiquitous, and their endospores can be present in food, in domestic animals, and on contaminated surfaces. Many spore-forming bacteria have been used in biotechnological applications, while others are human pathogens responsible for a wide range of critical clinical infections. Due to their resistant properties, it is challenging to eliminate spores and avoid the reactivation of latent spores that may lead to active infections. Furthermore, endospores play an essential role in the survival, transmission, and pathogenesis of some harmful strains that put human and animal health at risk. Thus, different methods have been applied for their eradication. Nevertheless, natural products are still a significant source for discovering and developing new antibiotics. Moreover, targeting the spore for clinical pathogens such as Clostridioides difficile is essential to disease prevention and therapeutics. These strategies could directly aim at the structural components of the spore or their germination process. This work summarizes the current advances in upcoming strategies and the development of natural products against endospores. This review also intends to highlight future perspectives in research and applications.
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Affiliation(s)
- Alba Romero-Rodríguez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
- Correspondence:
| | - Beatriz Ruiz-Villafán
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Claudia Fabiola Martínez-de la Peña
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72592, Mexico
| | - Sergio Sánchez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
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16
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Lv M, Huang J, Chen H, Zhang TT. An excimer lamp to provide far-ultraviolet C irradiation for dining-table disinfection. Sci Rep 2023; 13:381. [PMID: 36611088 PMCID: PMC9825099 DOI: 10.1038/s41598-023-27380-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
Dining tables may present a risk to diners by transmitting bacteria and/or viruses. Currently, there is a lack of an environmental-friendly and convenient means to protect diners when they are sitting together. This investigation constructed far-UVC excimer lamps to disinfect dining-table surfaces. The lamps were mounted at different heights and orientations, and the irradiance on table surfaces was measured. The irradiation doses to obtain different inactivation efficiencies for Escherichia coli (E. coli) were provided. In addition, numerical modeling was conducted for irradiance and the resulting inactivation efficiency. The surface-to-surface (S2S) model was validated with the measured irradiance. The germicidal performance of far-UVC irradiation, the far-UVC doses to which diners were exposed, and the risk of exposure to the generated ozone were evaluated. The results revealed that an irradiation dose of 12.8 mJ/cm2 can disinfect 99.9% of E. coli on surfaces. By varying the lamp irradiance output, the number and positions of the lamps, the far-UVC irradiation can achieve a 3-log reduction for a dining duration of 5 min. Besides, the far-UVC lamp has a low damage risk to diners when achieving an effective inactivation rate. Moreover, there is virtually no ozone exposure risk in a mechanically ventilated dining hall.
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Affiliation(s)
- Mengqiang Lv
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jin Huang
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Haofu Chen
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Tengfei Tim Zhang
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
- School of Civil Engineering, Dalian University of Technology, Dalian, China.
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17
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Alonso VPP, Furtado MM, Iwase CHT, Brondi-Mendes JZ, Nascimento MDS. Microbial resistance to sanitizers in the food industry: review. Crit Rev Food Sci Nutr 2022; 64:654-669. [PMID: 35950465 DOI: 10.1080/10408398.2022.2107996] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hygiene programs which comprise the cleaning and sanitization steps are part of the Good Hygiene Practices (GHP) and are considered essential to ensure food safety and quality. Inadequate hygiene practices may contribute to the occurrence of foodborne diseases, development of microbial resistance to sanitizers, and economic losses. In general, the sanitizer resistance is classified as intrinsic or acquired. The former is an inherent characteristic, naturally present in some microorganisms, whereas the latter is linked to genetic modifications that can occur at random or after continuous exposure to a nonnormal condition. The resistance mechanisms can involve changes in membrane permeability or in the efflux pump, and enzymatic activity. The efflux pump mechanism is the most elucidated in relation to the resistance caused by the use of different types of sanitizers. In addition, microbial resistance to sanitizers can also be favored in the presence of biofilms due to the protection given by the glycocalyx matrix and genetic changes. Therefore, this review aimed to show the main microbial resistance mechanisms to sanitizers, including genetic modifications, biofilm formation, and permeability barrier.
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Affiliation(s)
| | - Marianna Miranda Furtado
- Department of Food Science and Nutrition, University of Campinas - UNICAMP, Campinas, SP, Brazil
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18
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Malyshev D, Robinson NF, Öberg R, Dahlberg T, Andersson M. Reactive oxygen species generated by infrared laser light in optical tweezers inhibits the germination of bacterial spores. JOURNAL OF BIOPHOTONICS 2022; 15:e202200081. [PMID: 35538633 DOI: 10.1002/jbio.202200081] [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: 03/25/2022] [Revised: 04/28/2022] [Accepted: 05/08/2022] [Indexed: 06/14/2023]
Abstract
Bacterial spores are highly resistant to heat, radiation and various disinfection chemicals. The impact of these on the biophysical and physicochemical properties of spores can be studied on the single-cell level using optical tweezers. However, the effect of the trapping laser on spores' germination rate is not fully understood. In this work, we assess the impact of 1064 nm laser light on the germination of Bacillus thuringiensis spores. The results show that the germination rate of spores after laser exposure follows a sigmoid dose-response relationship, with only 15% of spores germinating after 20 J of laser light. Under anaerobic growth conditions, the percentage of germinating spores at 20 J increased to 65%. The results thereby indicate that molecular oxygen is a major contributor to the germination-inhibiting effect observed. Thus, our study highlights the risk for optical trapping of spores and ways to mitigate it.
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Affiliation(s)
| | | | - Rasmus Öberg
- Department of Physics, Umeå University, Umeå, Sweden
| | | | - Magnus Andersson
- Department of Physics, Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
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19
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Wang W, Rahman A, Huang Q, Vikesland PJ. Surface-enhanced Raman spectroscopy enabled evaluation of bacterial inactivation. WATER RESEARCH 2022; 220:118668. [PMID: 35689895 DOI: 10.1016/j.watres.2022.118668] [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: 02/28/2022] [Revised: 05/21/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
An improved understanding of bacterial inactivation mechanisms will provide useful insights for infectious disease control and prevention. We evaluated bacterial response to several inactivation methods using surface-enhanced Raman spectroscopy (SERS). The results indicate that changes in the SERS signal are highly related to cellular disruption and that cellular changes arising after cell inactivation cannot be ignored. The membrane integrity of heat and the combination of UV254 and free chlorine (UV254/chlorine) treated Pseudomonas syringae (P. syringae) cells were severely disrupted, leading to significantly increased peak intensities. Conversely, ethanol treated bacteria exhibited intact cell morphologies and the SERS spectra remained virtually unchanged. On the basis of time dependent SERS signals, we extracted dominant SERS patterns. Peaks related to nucleic acids accounted for the main changes observed during heat, UV254, and UV254/chlorine treatment, likely due to their outward diffusion from the cell cytoplasm. For free chlorine treated P. syringae, carbohydrates and proteins on the cell membrane were denatured or lost, resulting in a decrease in related peak intensities. The nucleobases were likely oxidized when treated with UV254 and chlorine, thus leading to shifts in the related peaks. The generality of the method was verified using two additional bacterial strains: Escherichia coli and Bacillus subtilis as well as in different water matrices. The results suggest that SERS spectral analysis is a promising means to examine bacterial stress response at the molecular level and has applicability in diverse environmental implementations.
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Affiliation(s)
- Wei Wang
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA; Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia 24061, USA
| | - Asifur Rahman
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA; Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia 24061, USA
| | - Qishen Huang
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA; Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia 24061, USA
| | - Peter J Vikesland
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA; Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia 24061, USA.
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20
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Chinchkar AV, Singh A, Singh SV, Acharya AM, Kamble MG. Potential sanitizers and disinfectants for fresh fruits and vegetables: A comprehensive review. J FOOD PROCESS PRES 2022. [DOI: 10.1111/jfpp.16495] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ajay V. Chinchkar
- Department of Food Science and Technology National Institute of Food Technology Entrepreneurship and Management Kundli, Sonipat Haryana‐131028 India
| | - Anurag Singh
- Department of Food Science and Technology National Institute of Food Technology Entrepreneurship and Management Kundli, Sonipat Haryana‐131028 India
| | - Sukh Veer Singh
- Department of Food Science and Technology National Institute of Food Technology Entrepreneurship and Management Kundli, Sonipat Haryana‐131028 India
| | | | - Meenatai G. Kamble
- Department of Food Science and Technology National Institute of Food Technology Entrepreneurship and Management Kundli, Sonipat Haryana‐131028 India
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21
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Malyshev D, Öberg R, Dahlberg T, Wiklund K, Landström L, Andersson PO, Andersson M. Laser induced degradation of bacterial spores during micro-Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 265:120381. [PMID: 34562861 DOI: 10.1016/j.saa.2021.120381] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/09/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
Micro-Raman spectroscopy combined with optical tweezers is a powerful method to analyze how the biochemical composition and molecular structures of individual biological objects change with time. In this work we investigate laser induced effects in the trapped object. Bacillus thuringiensis spores, which are robust organisms known for their resilience to light, heat, and chemicals are used for this study. We trap spores and monitor the Raman peak from CaDPA (calcium dipicolinic acid), which is a chemical protecting the spore core. We see a correlation between the amount of laser power used in the trap and the release of CaDPA from the spore. At a laser power of 5 mW, the CaDPA from spores in water suspension remain intact over the 90 min experiment, however, at higher laser powers an induced effect could be observed. SEM images of laser exposed spores (after loss of CaDPA Raman peak was confirmed) show a notable alteration of the spores' structure. Our Raman data indicates that the median dose exposure to lose the CaDPA peak was ∼60 J at 808 nm. For decontaminated/deactivated spores, i.e., treated in sodium hypochlorite or peracetic acid solutions, the sensitivity on laser power is even more pronounced and different behavior could be observed on spores treated by the two chemicals. Importantly, the observed effect is most likely photochemical since the increase of the spore temperature is in the order of 0.1 K as suggested by our numerical multiphysics model. Our results show that care must be taken when using micro-Raman spectroscopy on biological objects since photoinduced effects may substantially affect the results.
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Affiliation(s)
| | - Rasmus Öberg
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden
| | | | | | | | - Per Ola Andersson
- Swedish Defence Research Agency (FOI), Umeå, Sweden; Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Magnus Andersson
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), Umeå, Sweden.
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22
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Augustyn W, Chruściel A, Hreczuch W, Kalka J, Tarka P, Kierat W. Inactivation of Spores and Vegetative Forms of Clostridioides difficile by Chemical Biocides: Mechanisms of Biocidal Activity, Methods of Evaluation, and Environmental Aspects. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19020750. [PMID: 35055571 PMCID: PMC8775970 DOI: 10.3390/ijerph19020750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/15/2022]
Abstract
Clostridioides difficile infections (CDIs) are the most common cause of acquired diseases in hospitalized patients. Effective surface disinfection, focused on the inactivation of the spores of this pathogen, is a decisive factor in reducing the number of nosocomial cases of CDI infections. An efficient disinfection procedure is the result of both the properties of the biocidal agent used and the technology of its implementation as well as a reliable, experimental methodology for assessing the activity of the biocidal active substance based on laboratory models that adequately represent real clinical conditions. This study reviews the state of knowledge regarding the properties and biochemical basis of the action mechanisms of sporicidal substances, with emphasis on chlorine dioxide (ClO2). Among the analyzed biocides, in addition to ClO2, active chlorine, hydrogen peroxide, peracetic acid, and glutaraldehyde were characterized. Due to the relatively high sporicidal effectiveness and effective control of bacterial biofilm, as well as safety in a health and environmental context, the use of ClO2 is an attractive alternative in the control of nosocomial infections of CD etiology. In terms of the methods of assessing the biocidal effectiveness, suspension and carrier standards are discussed.
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Affiliation(s)
- Weronika Augustyn
- MEXEO-Wiesław Hreczuch, Energetyków 9, 47-225 Kędzierzyn-Koźle, Poland; (W.A.); (W.H.)
- Environmental Biotechnology Department, Silesian University of Technology, Faculty of Power and Environmental Engineering, 44-100 Gliwice, Poland;
| | - Arkadiusz Chruściel
- MEXEO-Wiesław Hreczuch, Energetyków 9, 47-225 Kędzierzyn-Koźle, Poland; (W.A.); (W.H.)
- Correspondence:
| | - Wiesław Hreczuch
- MEXEO-Wiesław Hreczuch, Energetyków 9, 47-225 Kędzierzyn-Koźle, Poland; (W.A.); (W.H.)
| | - Joanna Kalka
- Environmental Biotechnology Department, Silesian University of Technology, Faculty of Power and Environmental Engineering, 44-100 Gliwice, Poland;
| | - Patryk Tarka
- Department of Social Medicine and Public Health, Medical University of Warsaw, 02-007 Warszawa, Poland;
| | - Wojciech Kierat
- Department of Digital Systems, Silesian University of Technology, 44-100 Gliwice, Poland;
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23
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Prevalence and Antimicrobial Resistance of Paeniclostridium sordellii in Hospital Settings. Antibiotics (Basel) 2021; 11:antibiotics11010038. [PMID: 35052916 PMCID: PMC8772839 DOI: 10.3390/antibiotics11010038] [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] [Received: 12/13/2021] [Revised: 12/27/2021] [Accepted: 12/27/2021] [Indexed: 12/01/2022] Open
Abstract
(1) Background: The purpose of this study was to determine the prevalence of clostridia strains in a hospital environment in Algeria and to evaluate their antimicrobial susceptibility to antibiotics and biocides. (2) Methods: Five hundred surface samples were collected from surfaces in the intensive care unit and surgical wards in the University Hospital of Tlemcen, Algeria. Bacterial identification was carried out using MALDI-TOF-MS, and then the minimum inhibitory concentrations (MICs) of various antimicrobial agents were determined by the E-test method. P. sordellii toxins were searched by enzymatic and PCR assays. Seven products intended for daily disinfection in the hospitals were tested against Clostridium spp. spore collections. (3) Results: Among 100 isolates, 90 P. sordellii were identified, and all strains were devoid of lethal and hemorrhagic toxin genes. Beta-lactam, linezolid, vancomycin, tigecycline, rifampicin, and chloramphenicol all proved effective against isolated strains. Among all strains tested, the spores of P. sordellii exhibited remarkable resistance to the tested biocides compared to other Clostridium species. The (chlorine-based 0.6%, 30 min), (glutaraldehyde solution 2.5%, 30 min), and (hydrogen peroxide/peracetic acid 3%, 15 min) products achieved the required reduction in spores. (4) Conclusions: Our hospital’s current cleaning and disinfection methods need to be optimized to effectively remove spores from caregivers’ hands, equipment, and surfaces.
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24
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Näsström T, Dahlberg T, Malyshev D, Ådén J, Andersson PO, Andersson M, Karlsson BCG. Synthetic NAC 71-82 Peptides Designed to Produce Fibrils with Different Protofilament Interface Contacts. Int J Mol Sci 2021; 22:ijms22179334. [PMID: 34502242 PMCID: PMC8431055 DOI: 10.3390/ijms22179334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/17/2022] Open
Abstract
Alpha-synucleinopathies are featured by fibrillar inclusions in brain cells. Although α-synuclein fibrils display structural diversity, the origin of this diversity is not fully understood. We used molecular dynamics simulations to design synthetic peptides, based on the NAC 71-82 amino acid fragment of α-synuclein, that govern protofilament contacts and generation of twisted fibrillar polymorphs. Four peptides with structures based on either single or double fragments and capped or non-capped ends were selected for further analysis. We determined the fibrillar yield and the structures from these peptides found in the solution after fibrillisation using protein concentration determination assay and circular dichroism spectroscopy. In addition, we characterised secondary structures formed by individual fibrillar complexes using laser-tweezers Raman spectroscopy. Results suggest less mature fibrils, based on the lower relative β-sheet content for double- than single-fragment peptide fibrils. We confirmed this structural difference by TEM analysis which revealed, in addition to short protofibrils, more elongated, twisted and rod-like fibril structures in non-capped and capped double-fragment peptide systems, respectively. Finally, time-correlated single-photon counting demonstrated a difference in the Thioflavin T fluorescence lifetime profiles upon fibril binding. It could be proposed that this difference originated from morphological differences in the fibril samples. Altogether, these results highlight the potential of using peptide models for the generation of fibrils that share morphological features relevant for disease, e.g., twisted and rod-like polymorphs.
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Affiliation(s)
- Thomas Näsström
- Physical Pharmacy Laboratory, Linnaeus University Centre for Biomaterials Chemistry, Linnaeus University, SE-392 31 Kalmar, Sweden;
| | - Tobias Dahlberg
- The Biophysics and Biophotonics Group, Department of Physics, Umeå University, SE-901 87 Umeå, Sweden; (T.D.); (D.M.); (M.A.)
| | - Dmitry Malyshev
- The Biophysics and Biophotonics Group, Department of Physics, Umeå University, SE-901 87 Umeå, Sweden; (T.D.); (D.M.); (M.A.)
| | - Jörgen Ådén
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden;
| | - Per Ola Andersson
- Department of Material Science and Engineering, Applied Materials Science, Uppsala University, SE-751 03 Uppsala, Sweden;
| | - Magnus Andersson
- The Biophysics and Biophotonics Group, Department of Physics, Umeå University, SE-901 87 Umeå, Sweden; (T.D.); (D.M.); (M.A.)
| | - Björn C. G. Karlsson
- Physical Pharmacy Laboratory, Linnaeus University Centre for Biomaterials Chemistry, Linnaeus University, SE-392 31 Kalmar, Sweden;
- Correspondence:
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Dahlberg T, Andersson M. Optical design for laser tweezers Raman spectroscopy setups for increased sensitivity and flexible spatial detection. APPLIED OPTICS 2021; 60:4519-4523. [PMID: 34143005 DOI: 10.1364/ao.424595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
We demonstrate a method to double the collection efficiency in laser tweezers Raman spectroscopy (LTRS) by collecting both the forward-scattered and backscattered light in a single-shot multitrack measurement. Our method can collect signals at different sample volumes, granting both the pinpoint spatial selectivity of confocal Raman spectroscopy and the bulk sensitivity of non-confocal Raman spectroscopy simultaneously. Further, we display that our approach allows for reduced detector integration time and laser power. To show this, we measure the Raman spectra of both polystyrene beads and bacterial spores. For spores, we can trap them at 2.5 mW laser power and acquire a high signal-to-noise ratio power spectrum of the calcium-dipicolinic acid peaks using an integration time of ${2} \times {30}\;{\rm s}$. Thus, our method will enable the monitoring of biological samples sensitive to high intensities for longer times. Additionally, we demonstrate that by a simple modification, we can add polarization sensitivity and retrieve extra biochemical information.
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Nilsson DPG, Dahlberg T, Andersson M. Step-by-step guide to 3D print motorized rotation mounts for optical applications. APPLIED OPTICS 2021; 60:3764-3771. [PMID: 33983309 DOI: 10.1364/ao.422695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Motorized rotation mounts and stages are versatile instruments that introduce computer control to optical systems, enabling automation and scanning actions. They can be used for intensity control, position adjustments, etc. However, these rotation mounts come with a hefty price tag, and this limits their use. This work shows how to build two different types of motorized rotation mounts for $1^{\prime \prime}$ optics, using a 3D printer and off-the-shelf components. The first is intended for reflective elements, such as mirrors and gratings, and the second for transmissive elements, such as polarizers and retarders. We evaluate and compare their performance to commercial systems based on velocity, resolution, precision, backlash, and axis wobble. Also, we investigate the angular stability using Allan variance analysis. The results show that our mounts perform similarly to systems costing as much as $\$ 2500\,\rm USD $, while also being quick to build and costing less than $\$ 220\,\rm USD$. As a proof of concept, we show how to control lasers used in an optical tweezers and Raman spectroscopy setup. When used for this, the 3D printed motorized rotational mounts provide intensity control with a resolution of 0.03 percentage points or better.
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