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Soukupova H, Rehorova V, Cibulkova I, Duska F. Assessment of Faecal Microbiota Transplant Stability in Deep-Freeze Conditions: A 12-Month Ex Vivo Viability Analysis. J Clin Lab Anal 2024; 38:e25023. [PMID: 38544348 PMCID: PMC11033324 DOI: 10.1002/jcla.25023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/15/2024] [Accepted: 02/19/2024] [Indexed: 04/23/2024] Open
Abstract
BACKGROUND Faecal microbiota transplantation (FMT) is an established treatment for Clostridioides difficile infection and is under investigation for other conditions. The availability of suitable donors and the logistics of fresh stool preparation present challenges, making frozen, biobanked stools an attractive alternative. AIMS This study aimed to evaluate the long-term viability of bacterial populations in faecal samples stored at -80°C for up to 12 months, supporting the feasibility of using frozen grafts for FMT. METHODS Fifteen faecal samples from nine healthy donors were processed, mixed with cryoprotectants and stored at -80°C. Samples were assessed at baseline and after 3, 6 and 12 months using quantitative culturing methods to determine the concentration of live bacteria. RESULTS Quantitative analysis showed no significant decrease in bacterial viability over the 12-month period for both aerobic and anaerobic cultures (p = 0.09). At all timepoints, the coefficients of variability in colony-forming unit (CFU) counts were greater between samples (102 ± 21% and 100 ± 13% for aerobic and anaerobic cultures, respectively) than the variability between measurements of the same sample (30 ± 22% and 30 ± 19%). CONCLUSIONS The study confirmed that faecal microbiota can be preserved with high viability in deep-freeze storage for up to a year, making allogenic FMT from biobanked samples a viable and safer option for patients. However, a multidonor approach may be beneficial to mitigate the risk of viability loss in any single donor sample.
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Affiliation(s)
- Hana Soukupova
- Department of Microbiology, The Third Faculty of MedicineCharles University and Kralovske Vinohrady University HospitalPragueCzech Republic
| | - Veronika Rehorova
- Department of Anaesthesia and Intensive Care Medicine, The Third Faculty of MedicineCharles University and Kralovske Vinohrady University HospitalPragueCzech Republic
| | - Ivana Cibulkova
- Division of Gastroenterology, Department of MedicineKralovske Vinohrady University HospitalPragueCzech Republic
| | - Frantisek Duska
- Department of Anaesthesia and Intensive Care Medicine, The Third Faculty of MedicineCharles University and Kralovske Vinohrady University HospitalPragueCzech Republic
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Chiang J, Robertson J, McGoverin CM, Swift S, Vanholsbeeck F. Rapid detection of viable microbes with 5-cyano-2,3-di-(p-tolyl)tetrazolium chloride and 5(6)-carboxyfluorescein diacetate using a fibre fluorescence spectroscopy system. J Appl Microbiol 2024; 135:lxae047. [PMID: 38383865 DOI: 10.1093/jambio/lxae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/03/2024] [Accepted: 02/20/2024] [Indexed: 02/23/2024]
Abstract
AIMS To assess the efficacy of two commercially available viability dyes, 5-cyano-2,3-di-(p-tolyl)tetrazolium chloride (CTC) and 5(6)-carboxyfluorescein diacetate (CFDA), in reporting on viable cell concentration and species using an all-fibre fluorometer. METHODS AND RESULTS Four bacterial species (two Gram-positive and two Gram-negative) commonly associated with food poisoning or food spoilage (Escherichia coli, Salmonella enterica, Staphylococcus aureus, and Bacillus cereus) were stained with CTC or CFDA and the fibre fluorometer was used to collect full fluorescence emission spectra. A good correlation between concentration and fluorescence intensity was found for Gram-negative bacteria between 107 and 108 colony-forming units (CFU) ml-1. There was no correlation with concentration for Gram-positive bacteria; however, the information in the CTC and CFDA spectra shows the potential to distinguish Gram-negative cells from Gram-positive cells, although it may simply reflect the overall bacterial metabolic activity under staining conditions from this study. CONCLUSIONS The limit of detection (LoD) is too high in the dip-probe approach for analysis; however, the development of an approach measuring the fluorescence of single cells may improve this limitation. The development of new bacteria-specific fluorogenic dyes may also address this limitation. The ability to differentiate bacteria using these dyes may add value to measurements made to enumerate bacteria using CTC and CFDA.
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Affiliation(s)
- Jessica Chiang
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1023, New Zealand
| | - Julia Robertson
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1023, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland 1010, New Zealand
| | - Cushla M McGoverin
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland 1010, New Zealand
- Department of Physics, The University of Auckland, Auckland 1010, New Zealand
| | - Simon Swift
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1023, New Zealand
| | - Frédérique Vanholsbeeck
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland 1010, New Zealand
- Department of Physics, The University of Auckland, Auckland 1010, New Zealand
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Amaechi BT, Mohseni S, Dillow AM, Abdul Azees PA, Movaghari Pour F, Kataoka Y, Restrepo MC. Investigation of the effects of Bipolar Radiofrequency Energy on the Structural Morphology of Dental Plaque. Eur J Dent 2024; 18:243-252. [PMID: 37172943 PMCID: PMC10959635 DOI: 10.1055/s-0043-1764427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
OBJECTIVES To investigate the effects of radiofrequency (RF) energy, applied through a power toothbrush, on the structural morphology of dental plaque and its bacteria components. Previous studies showed that a toothbrush powered by RF (ToothWave) effectively reduces extrinsic tooth stains, plaque, and calculus. However, the mechanism by which it reduces dental plaque deposits is not fully established. MATERIALS AND METHODS Multispecies plaques at sampling time points of 24, 48, and 72 hours were treated with the application of RF using ToothWave with the toothbrush bristles 1 mm above the plaque surface. Groups that underwent the same protocol but without RF treatment served as paired controls. Confocal laser scanning microscope (CLSM) was used to determine cell viability at each time point. Plaque morphology and bacteria ultrastructure were viewed using scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. STATISTICAL ANALYSIS Data were analyzed statistically using analysis of variance (ANOVA) and Bonferroni post-tests. RESULTS At each time, RF treatment significantly (p < 0.05) reduced the viable cells in plaque and caused a substantial disruption of plaque morphology, while the untreated plaque had intact morphology. Cells in treated plaques showed disrupted cell walls, cytoplasmic material, huge vacuoles, and heterogeneity in electron density, while these organelles remained intact in untreated plaques. CONCLUSION The application of RF via a power toothbrush can disrupt plaque morphology and kill bacteria. These effects were enhanced by the combined application of RF and toothpaste.
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Affiliation(s)
- Bennett T. Amaechi
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
| | - Sahar Mohseni
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
| | - Andrew M. Dillow
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
| | - Parveez Ahamed Abdul Azees
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
| | - Fatemeh Movaghari Pour
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
| | - Yuko Kataoka
- Department of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States
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Koutroulis A, Valen H, Ørstavik D, Kapralos V, Camilleri J, Sunde PT. Antibacterial Activity of Root Repair Cements in Contact with Dentin-An Ex Vivo Study. J Funct Biomater 2023; 14:511. [PMID: 37888176 PMCID: PMC10607193 DOI: 10.3390/jfb14100511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/18/2023] [Accepted: 10/08/2023] [Indexed: 10/28/2023] Open
Abstract
This study assessed the antibacterial characteristics of the dentin/material interface and dentin surfaces exposed to experimental hydraulic calcium silicate cement (HCSC) with or without bioactive glass (BG) replacement (20% or 40%) or mixed with a silver nanoparticle (SNP) solution (1 or 2 mg/mL), and Biodentine, TotalFill BC RRM putty and Intermediate Restorative Material (IRM). Human root dentin segments with test materials were assessed at 1 or 28 days. In one series, the specimens were split to expose the dentin and material surfaces. A 24 h direct contact test was conducted against three-day established Enterococcus faecalis and Pseudomonas aeruginosa monospecies biofilms. In another series, the dentin/material interface of intact specimens was exposed to biofilm membranes for 3 days and the antibacterial activity was assessed via confocal microscopy. The interface was additionally characterised. All one-day material and dentin surfaces were antibacterial. Dentin surfaces exposed to HCSC with 40% BG-replacement, Biodentine and IRM had decreased antibacterial properties compared to those of the other cements. The HCSC mixed with a 2 mg/mL SNP solution had the highest antimicrobial effect in the confocal assay. The interfacial characteristics of HCSCs were similar. The test materials conferred antibacterial activity onto the adjacent dentin. The BG reduced the antibacterial effect of dentin exposed to HCSC; a 2 mg/mL SNP solution increased the antibacterial potential for longer interaction periods (three-day exposure).
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Affiliation(s)
- Andreas Koutroulis
- Section of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, 0317 Oslo, Norway; (D.Ø.); (V.K.)
| | - Håkon Valen
- Nordic Institute of Dental Materials (NIOM), 0855 Oslo, Norway;
| | - Dag Ørstavik
- Section of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, 0317 Oslo, Norway; (D.Ø.); (V.K.)
| | - Vasileios Kapralos
- Section of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, 0317 Oslo, Norway; (D.Ø.); (V.K.)
| | - Josette Camilleri
- School of Dentistry, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - Pia Titterud Sunde
- Section of Endodontics, Institute of Clinical Dentistry, Faculty of Dentistry, University of Oslo, 0317 Oslo, Norway; (D.Ø.); (V.K.)
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Bénard MV, Arretxe I, Wortelboer K, Harmsen HJM, Davids M, de Bruijn CMA, Benninga MA, Hugenholtz F, Herrema H, Ponsioen CY. Anaerobic Feces Processing for Fecal Microbiota Transplantation Improves Viability of Obligate Anaerobes. Microorganisms 2023; 11:2238. [PMID: 37764082 PMCID: PMC10535047 DOI: 10.3390/microorganisms11092238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Fecal microbiota transplantation (FMT) is under investigation for several indications, including ulcerative colitis (UC). The clinical success of FMT depends partly on the engraftment of viable bacteria. Because the vast majority of human gut microbiota consists of anaerobes, the currently used aerobic processing protocols of donor stool may diminish the bacterial viability of transplanted material. This study assessed the effect of four processing techniques for donor stool (i.e., anaerobic and aerobic, both direct processing and after temporary cool storage) on bacterial viability. By combining anaerobic culturing on customized media for anaerobes with 16S rRNA sequencing, we could successfully culture and identify the majority of the bacteria present in raw fecal suspensions. We show that direct anaerobic processing of donor stool is superior to aerobic processing conditions for preserving the bacterial viability of obligate anaerobes and butyrate-producing bacteria related to the clinical response to FMT in ulcerative colitis patients, including Faecalibacterium, Eubacterium hallii, and Blautia. The effect of oxygen exposure during stool processing decreased when the samples were stored long-term. Our results confirm the importance of sample conditioning to preserve the bacterial viability of oxygen-sensitive gut bacteria. Anaerobic processing of donor stool may lead to increased clinical success of FMT, which should further be investigated in clinical trials.
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Affiliation(s)
- Mèlanie V. Bénard
- Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (M.V.B.); (I.A.); (C.M.A.d.B.); (M.A.B.)
- Department of Endocrinology and Metabolism, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Iñaki Arretxe
- Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (M.V.B.); (I.A.); (C.M.A.d.B.); (M.A.B.)
| | - Koen Wortelboer
- Department of Experimental Vascular Medicine, Amsterdam Cardiovascular Sciences (ACS), Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (K.W.); (M.D.); (H.H.)
| | - Hermie J. M. Harmsen
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands;
| | - Mark Davids
- Department of Experimental Vascular Medicine, Amsterdam Cardiovascular Sciences (ACS), Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (K.W.); (M.D.); (H.H.)
| | - Clara M. A. de Bruijn
- Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (M.V.B.); (I.A.); (C.M.A.d.B.); (M.A.B.)
- Pediatric Gastroenterology, Hepatology and Nutrition, Emma Children’s Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Amsterdam Reproduction & Development Research Institute, Emma Children’s Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Marc A. Benninga
- Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (M.V.B.); (I.A.); (C.M.A.d.B.); (M.A.B.)
- Pediatric Gastroenterology, Hepatology and Nutrition, Emma Children’s Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Amsterdam Reproduction & Development Research Institute, Emma Children’s Hospital, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Floor Hugenholtz
- Center for Experimental and Molecular Medicine, Amsterdam Medical Center, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
| | - Hilde Herrema
- Department of Experimental Vascular Medicine, Amsterdam Cardiovascular Sciences (ACS), Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (K.W.); (M.D.); (H.H.)
| | - Cyriel Y. Ponsioen
- Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; (M.V.B.); (I.A.); (C.M.A.d.B.); (M.A.B.)
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6
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Acosta EM, Little KA, Bratton BP, Lopez JG, Mao X, Payne AS, Donia M, Devenport D, Gitai Z. Bacterial DNA on the skin surface overrepresents the viable skin microbiome. eLife 2023; 12:RP87192. [PMID: 37389570 DOI: 10.7554/elife.87192] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Abstract
The skin microbiome provides vital contributions to human health. However, the spatial organization and viability of its bacterial components remain unclear. Here, we apply culturing, imaging, and molecular approaches to human and mouse skin samples, and find that the skin surface is colonized by fewer viable bacteria than predicted by bacterial DNA levels. Instead, viable skin-associated bacteria are predominantly located in hair follicles and other cutaneous invaginations. Furthermore, we show that the skin microbiome has a uniquely low fraction of viable bacteria compared to other human microbiome sites, indicating that most bacterial DNA on the skin surface is not associated with viable cells Additionally, a small number of bacterial families dominate each skin site and traditional sequencing methods overestimate both the richness and diversity of the skin microbiome. Finally, we performed an in vivo skin microbiome perturbation-recovery study using human volunteers. Bacterial 16S rRNA gene sequencing revealed that, while the skin microbiome is remarkably stable even in the wake of aggressive perturbation, repopulation of the skin surface is driven by the underlying viable population. Our findings help explain the dynamics of skin microbiome perturbation as bacterial DNA on the skin surface can be transiently perturbed but is replenished by a stable underlying viable population. These results address multiple outstanding questions in skin microbiome biology with significant implications for future efforts to study and manipulate it.
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Affiliation(s)
- Ellen M Acosta
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Katherine A Little
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Benjamin P Bratton
- Department of Molecular Biology, Princeton University, Princeton, United States
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
- Department of Pathology, Immunology and Microbiology, Vanderbilt University Medical Center, Nashville, United States
- Vanderbilt Institute for Infection, Immunology and Inflammation,, Nashville, United States
| | - Jaime G Lopez
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
| | - Xuming Mao
- Department of Dermatology, University of Pennsylvania, Philadelphia, United States
| | - Aimee S Payne
- Department of Dermatology, University of Pennsylvania, Philadelphia, United States
| | - Mohamed Donia
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Danelle Devenport
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, United States
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7
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Rakotonirina A, Galperine T, Audry M, Kroemer M, Baliff A, Carrez L, Sadeghipour F, Schrenzel J, Guery B, Allémann É. Dry alginate beads for fecal microbiota transplantation: from model strains to fecal samples. Int J Pharm 2023; 639:122961. [PMID: 37075927 DOI: 10.1016/j.ijpharm.2023.122961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 04/21/2023]
Abstract
Clostridioides difficile infection (CDI) is a critical nosocomial infection with more than 124,000 cases per year in Europe and a mortality rate of 15-17%. The standard of care (SoC) is antibiotic treatment. Unfortunately, the relapse rate is high (∼35%) and SoC is significantly less effective against recurrent infection (rCDI). Fecal microbiota transplantation (FMT) is a recommended treatment against rCDI from the second recurrence episode and has an efficacy of 90%. The formulation of diluted donor stool deserves innovation because its actual administration routes deserve optimization (naso-duodenal/jejunal tubes, colonoscopy, enema or several voluminous oral capsules). Encapsulation of model bacteria strains in gel beads were first investigated. Then, the encapsulation method was applied to diluted stools. Robust spherical gel beads were obtained. The mean particle size was around 2 mm. A high loading of viable microorganisms was obtained for model strains and fecal samples. For plate-counting, values ranged from 1015 to 1017 CFU/g for single and mixed model strains, and 106 to 108 CFU/g for fecal samples. This corresponded to a viability of 30% to 60% as assessed by flow cytometry. This novel formulation is promising as the technology is applicable to both model strains and bacteria contained in the gut microbiota.
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Affiliation(s)
- Adèle Rakotonirina
- School of Pharmaceutical Sciences, University of Geneva, 1211 Geneva, Switzerland; Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland
| | - Tatiana Galperine
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, 1011 & 1015 Lausanne, Switzerland; French Group of Faecal Microbiota Transplantation, Paris, France
| | - Maxime Audry
- Service of Pharmacy, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Marie Kroemer
- Service of Pharmacy, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Aurélie Baliff
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, 1011 & 1015 Lausanne, Switzerland
| | - Laurent Carrez
- Service of Pharmacy, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Farshid Sadeghipour
- School of Pharmaceutical Sciences, University of Geneva, 1211 Geneva, Switzerland; Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland; Service of Pharmacy, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Jacques Schrenzel
- Genomic Research Lab, Service of Infectious Diseases, Geneva University Hospitals and University of Geneva, 1211 Geneva, Switzerland
| | - Benoît Guery
- Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, 1011 & 1015 Lausanne, Switzerland
| | - Éric Allémann
- School of Pharmaceutical Sciences, University of Geneva, 1211 Geneva, Switzerland; Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1211 Geneva, Switzerland.
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Cichońska P, Kowalska E, Ziarno M. The Survival of Psychobiotics in Fermented Food and the Gastrointestinal Tract: A Review. Microorganisms 2023; 11:microorganisms11040996. [PMID: 37110420 PMCID: PMC10142889 DOI: 10.3390/microorganisms11040996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
In recent years, scientists have been particularly interested in the gut-brain axis, as well as the impact of probiotics on the nervous system. This has led to the creation of the concept of psychobiotics. The present review describes the mechanisms of action of psychobiotics, their use in food products, and their viability and survival during gastrointestinal passage. Fermented foods have a high potential of delivering probiotic strains, including psychobiotic ones. However, it is important that the micro-organisms remain viable in concentrations ranging from about 106 to 109 CFU/mL during processing, storage, and digestion. Reports indicate that a wide variety of dairy and plant-based products can be effective carriers for psychobiotics. Nonetheless, bacterial viability is closely related to the type of food matrix and the micro-organism strain. Studies conducted in laboratory conditions have shown promising results in terms of the therapeutic properties and viability of probiotics. Because human research in this field is still limited, it is necessary to broaden our understanding of the survival of probiotic strains in the human digestive tract, their resistance to gastric and pancreatic enzymes, and their ability to colonize the microbiota.
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Affiliation(s)
- Patrycja Cichońska
- Department of Food Technology and Assessment, Institute of Food Science, Warsaw University of Life Sciences-SGGW (WULS-SGGW), Nowoursynowska 159c St., 02-776 Warsaw, Poland
| | - Ewa Kowalska
- Department of Food Technology and Assessment, Institute of Food Science, Warsaw University of Life Sciences-SGGW (WULS-SGGW), Nowoursynowska 159c St., 02-776 Warsaw, Poland
| | - Małgorzata Ziarno
- Department of Food Technology and Assessment, Institute of Food Science, Warsaw University of Life Sciences-SGGW (WULS-SGGW), Nowoursynowska 159c St., 02-776 Warsaw, Poland
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9
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Chen Y, Caneli G, Xie D. A PMMA bone cement with improved antibacterial function and flexural strength. J Biomater Sci Polym Ed 2022; 33:1398-1414. [PMID: 35321628 DOI: 10.1080/09205063.2022.2056943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/16/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
A novel non-leaching antibacterial bone cement has been developed and evaluated. An antibacterial furanone derivative was synthesized and covalently coated onto the surface of alumina filler particles, followed by mixing into a conventional poly(methyl methacrylate) bone cement. Flexural strength and bacterial viability were used to evaluate the modified cements. Effects of coated antibacterial moiety content, coated alumina filler particle size and loading were investigated. Results showed that almost all the modified cements showed higher flexural strength (up to 10%), flexural modulus (up to 18%), and antibacterial activity (up to 67% to S. aureus and up to 84% to E. coli), as compared to original poly(methyl methacrylate) cement. Increasing antibacterial moiety and filler loading significantly enhanced antibacterial activity. On the other hand, increasing coated filler particle size decreased antibacterial activity. Increasing antibacterial moiety content and particle size did not significantly affect flexural strength and modulus. Increasing filler loading did not significantly affect flexural modulus but reduced flexural strength. Antibacterial agent leaching tests showed that it seems no leachable antibacterial component from the modified experimental cement to the surrounding environment. Within the limitations of this study, the modified poly(methyl methacrylate) bone cement may potentially be developed into a clinically useful bone cement for reducing in-surgical and post-surgical infection.
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Affiliation(s)
- Yong Chen
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
- Jinchu University, Hubei, P.R. China
| | - Gulsah Caneli
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
| | - Dong Xie
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana, USA
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Oguadinma IC, Mishra A, Juneja VK, Dev Kumar G. Antibiotic Resistance Influences Growth Rates and Cross-Tolerance to Lactic Acid in Escherichia coli O157:H7 H1730. Foodborne Pathog Dis 2022; 19:622-629. [PMID: 35856661 DOI: 10.1089/fpd.2022.0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli O157:H7-contaminated beef has been implicated in numerous foodborne outbreaks. Contamination occurs despite the use of antimicrobial interventions such as lactic acid (LA). In addition, resistance to antibiotics such as ampicillin and streptomycin among isolates has been frequently reported. The influence of antibiotic resistance (ABR) on growth rates and cross-tolerance of lettuce isolate E. coli O157:H7 H1730 to LA was evaluated. Antibiotic-resistant strain variants were generated by conferring resistance to either ampicillin (ampC) or streptomycin (strepC) or both ampicillin and streptomycin (ampC strepC) through incremental exposure to the antibiotics. Ampicillin resistance was also conferred by plasmid transformation to generate the ampP and ampP strepC strains. The minimum inhibitory concentration of LA on all the strains evaluated was 0.375% v/v. The lag phase duration of all strains except E. coli O157:H7 ampP strepC increased with increasing concentration of LA. The ampP strepC and ampC strains were most tolerant to 5% LA with declines in the cell population of 2.86 and 2.56 log CFU/mL, respectively (p < 0.05). The ampP strepC strain was the most tolerant when evaluated by the live/dead viability assay. The addition of the efflux pump inhibitor, carbonyl cyanide m-chlorophenylhydrazone, with 2.5% LA resulted in a significant increase in sensitivity in the no resistance (NR) wild-type and ampC strains, resulting in 6.62 and 6.65 log CFU/mL reduction, respectively, while the highly tolerant ampP strepC strain had a 2.90 log CFU/mL decrease. Tolerance to LA was significantly influenced by both the ABR profile of the strain and LA concentration. The results from this study indicate that E. coli O157:H7 strains with certain ABR profiles might be more tolerant to LA.
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Affiliation(s)
- Ikechukwu Chukwuma Oguadinma
- Center for Food Safety, College of Agriculture and Environmental Sciences, University of Georgia, Griffin, Georgia, USA
| | - Abhinav Mishra
- Department of Food Science & Technology, University of Georgia, Athens, Georgia, USA
| | - Vijay K Juneja
- Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania, USA
| | - Govindaraj Dev Kumar
- Center for Food Safety, College of Agriculture and Environmental Sciences, University of Georgia, Griffin, Georgia, USA
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11
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Gonca S, Özdemir S, Yefimova S, Tkachenko A, Onishchenko A, Klochkov V, Kavok N, Maksimchuk P, Dizge N, Ocakoglu K. Experimental Confirmation of Antimicrobial Effects of GdYVO 4:Eu 3+ Nanoparticles. Drug Dev Ind Pharm 2022; 47:1966-1974. [PMID: 35514217 DOI: 10.1080/03639045.2022.2075007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nanotechnology can be applied to design antibacterial agents to combat antibiotic resistance. The aim of the present study was to assess the antimicrobial effects and cytotoxicity of GdYVO4:Eu3+ nanoparticles (NPs). Biofilm inhibition activity, antimicrobial activity, bacterial viability inhibition and DNA cleavage activity of GdYVO4:Eu3+ NPs were studied. In addition, the impact of GdYVO4:Eu3+ NPs on the mitochondrial membrane potential (ΔΨM) of host immune cells and, hence, their apoptosis was analyzed by JC-1 staining using flow cytometry. GdYVO4:Eu3+ NPs demonstrated good antimicrobial, cell viability inhibition and DNA cleavage activities. In addition, GdYVO4:Eu3+ NPs showed good biofilm inhibition activity against S. aureus and P. aeruginosa and inhibition percentages were 89.15% and 79.54%, respectively. However, GdYVO4:Eu3+ NPs promoted mitochondrial depolarization and apoptosis of leukocytes at high concentrations. GdYVO4:Eu3+ nanoparticles are promising antibacterial agents. However, more efforts should be exerted to ensure their safety.
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Affiliation(s)
- Serpil Gonca
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Mersin, Turkey, TR-33343 Yenisehir, Mersin, Turkey
| | - Sadin Özdemir
- Food Processing Programme, Technical Science Vocational School, Mersin University, TR-33343 Yenisehir, Mersin, Turkey
| | - Svetlana Yefimova
- Institute for Scintillation Materials National Academy of Sciences of Ukraine, 61072 Kharkiv, Ukraine
| | - Anton Tkachenko
- Research Institute of Experimental and Clinical Medicine, Kharkiv National Medical University, 61022 Kharkiv, Ukraine
| | - Anatolii Onishchenko
- Research Institute of Experimental and Clinical Medicine, Kharkiv National Medical University, 61022 Kharkiv, Ukraine
| | - Vladimir Klochkov
- Institute for Scintillation Materials National Academy of Sciences of Ukraine, 61072 Kharkiv, Ukraine
| | - Nataliya Kavok
- Institute for Scintillation Materials National Academy of Sciences of Ukraine, 61072 Kharkiv, Ukraine
| | - Pavel Maksimchuk
- Institute for Scintillation Materials National Academy of Sciences of Ukraine, 61072 Kharkiv, Ukraine
| | - Nadir Dizge
- Mersin University, Department of Environmental Engineering, 33343 Yenisehir, Mersin, Turkey
| | - Kasim Ocakoglu
- Tarsus University, Faculty of Engineering, Department of Engineering Fundamental Sciences, 33400, Tarsus, Turkey
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12
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Benov L. Improved Formazan Dissolution for Bacterial MTT Assay. Microbiol Spectr 2021; 9:e0163721. [PMID: 34937171 DOI: 10.1128/spectrum.01637-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The MTT assay, based on the enzymatic reduction of the water-soluble, yellowish tetrazolium salt 3-(4,5-dimethylthiazol)-2,5-diphenyl-tetrazolium bromide (MTT) to purple formazan, is commonly used for assessment of cell viability and proliferation. Accurate performance by the MTT assay depends on complete solubilization of cells and formazan and stability of the colored solution. Comparison of different solubilization solutions revealed that dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), buffered with ammonia buffer, pH 10, and containing 5% SDS, produced the best results. These two solvents provided rapid and complete solubilization of formazan and cells, with minimal background absorbance at 700 nm, good reproducibility (low interassay coefficient of variation), high sensitivity, and color stability for at least 24 h. A linear relationship between viable-cell number and formazan absorbance was preserved for cell densities up to ∼1 × 109 cells/mL for Gram-negative and Gram-positive microorganisms. Since MTT can be reduced by medium components in the absence of cells, blanks containing all medium components but no cells should be run simultaneously. Measurements at two wavelengths, one corresponding to absorption peak of formazan (570 nm) and a background absorbance far from the peak (700 nm), are necessary to avoid artifacts due to incomplete solubilization and turbidity. IMPORTANCE Reduction of the water-soluble tetrazolium salt 3-(4,5-dimethylthiazol)-2,5 diphenyl-tetrazolium bromide (MTT) to purple, water-insoluble formazan is commonly used for assessment of cell viability and proliferation. Spectrophotometric detection of formazan requires its solubilization. The solubilization solvent has a strong influence on data acquisition and often introduces artifacts, leading to misreading of results. This study offers a choice of solvents that minimize solubilization artifacts when the MTT test is applied to microbiological cultures.
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13
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Zhang Q, Wang X, Kang Y, Sun H, Liang Y, Liu J, Su Z, Dan J, Luo L, Yue T, Wang J, Zhang W. Natural Products Self-Assembled Nanozyme for Cascade Detection of Glucose and Bacterial Viability in Food. Foods 2021; 10:foods10112596. [PMID: 34828877 PMCID: PMC8618841 DOI: 10.3390/foods10112596] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 01/22/2023] Open
Abstract
Sugar content and bacterial contamination levels are important indicators for the health and safety of food, respectively. Therefore, it is important to construct a method that can detect both glucose and bacterial activity. Herein, natural compounds (gallic acid and glucose oxidase) were assembled into nanozyme (GOx@GA-Fe (ii)) for mild cascade detection. The nanozyme catalyzes glucose to produce hydrogen peroxide, which is then converted to ·OH and oxidized colorless TMB from blue oxidized TMB. Under the optimal conditions, the method has a good linear relationship in the glucose concentration range of 1–500 μM (R2 = 0.993) with minimum detection concentration of 0.43 μM. Based on the glucose consumption of bacteria metabolism, the cascade reaction was then applied to detect the viability of 5 common bacteria. As such, a cascade method based on a natural self-assembled nanozyme was fabricated to monitor the quality of food.
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14
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Burgard N, Kienitz M, Jourdan C, Rüttermann S. The Influence of Modified Experimental Dental Resin Composites on the Initial In Situ Biofilm-A Triple-Blinded, Randomized, Controlled Split-Mouth Trial. Polymers (Basel) 2021; 13:2814. [PMID: 34451352 DOI: 10.3390/polym13162814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 01/27/2023] Open
Abstract
The purpose of the study was to investigate the bacterial viability of the initial biofilm on the surface of experimental modified dental resin composites. Twenty-five healthy individuals with good oral hygiene were included in this study. In a split-mouth design, they received acrylic splints with five experimental composite resin specimens. Four of them were modified with either a novel polymeric hollow-bead delivery system or methacrylated polymerizable Irgasan (Antibacterial B), while one specimen served as an unmodified control (ST). A delivery system based on Poly-Pore® was loaded with one of the active agents: Tego® Protect 5000 (Antiadhesive A), Dimethicone (Antiadhesive B), or Irgasan (Antibacterial A). All study subjects refrained from toothbrushing during the study period. Specimens were detached from the splints after 8 h and given a live/dead staining before fluorescence microscopy. A Friedman test and a post hoc Nemenyi test were applied with a significance level at p < 0.05. In summary, all materials but Antibacterial B showed a significant antibacterial effect compared to ST. The results suggested the role of the materials’ chemistry in the dominance of cell adhesion. In conclusion, dental resin composites with Poly-Pore-loaded active agents showed antibacterial effectiveness in situ.
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15
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Oliveira MM, de Almeida FA, Baglinière F, de Oliveira LL, Vanetti MCD. Behavior of Salmonella Enteritidis and Shigella flexneri during induction and recovery of the viable but nonculturable state. FEMS Microbiol Lett 2021; 368:6316107. [PMID: 34227668 DOI: 10.1093/femsle/fnab087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/02/2021] [Indexed: 11/12/2022] Open
Abstract
Bacteria may enter into a viable but nonculturable (VBNC) state as a response to stresses, such as those found in food processing. Cells in the VBNC state lose the ability to grow in a conventional culture medium but man recover culturability. The viability, culturability and intracellular reactive oxygen species (ROS) of Salmonella Enteritidis and Shigella flexneri were evaluated under stress conditions to induce a VBNC state. Cells were maintained under nutritional, osmotic and cold stresses (long-term induction) in Butterfield's phosphate solution plus 1.2 M of NaCl at 4°C and under nutritional and oxidative stresses (short-term induction) in 10 mM of H2O2. Culture media, recovery agents, sterilization methods of media and incubation temperature, were combined and applied to recover the culturability of the VBNC cells. Salmonella entered in the VBNC state after 135 days under long-term induction, while Shigella maintained culturability after 240 days. Under short-term induction, Salmonella and Shigella lose culturability after 135 and 240 min, respectively. Flow cytometric analysis revealed viable cells and intracellular ROS in both species in VBNC. It was not possible to recover the culturability of VBNC cells using the 42 combinations of different factors.
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Affiliation(s)
- Mayara Messias Oliveira
- Department of Microbiology, Universidade Federal de Viçosa (UFV), Viçosa, MG, 36570-450, Brazil.,Department of Food Science, Universidade Estadual de Campinas (Unicamp), Campinas, SP, 13084-654, Brazil
| | - Felipe Alves de Almeida
- Department of Nutrition, Universidade Federal de Juiz de Fora (UFJF), Governador Valadares, MG, 35032-620, Brazil
| | - François Baglinière
- Department of Microbiology, Universidade Federal de Viçosa (UFV), Viçosa, MG, 36570-450, Brazil
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16
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Jakubovskis R, Jankutė A, Guobužaitė S, Boris R, Urbonavičius J. Prolonging Bacterial Viability in Biological Concrete: Coated Expanded Clay Particles. Materials (Basel) 2021; 14:2719. [PMID: 34064142 DOI: 10.3390/ma14112719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/16/2022]
Abstract
One of the biggest challenges in the development of a biological self-healing concrete is to ensure the long-term viability of bacteria that are embedded in the concrete. In the present study, a coated expanded clay (EC) is investigated for its potential use as a bacterial carrier in biological concrete. Eight different materials for coatings were selected considering cost, workability and accessibility in the construction industry. Long-term (56 days) viability analysis was conducted with a final evaluation of each coating performance. Our results indicate that healing efficiency in biological concrete specimens is strongly related to viable bacteria present in the healing agent. More viable bacteria-containing specimens exhibited a higher crack closure ratio. Our data suggest that the additional coating of EC particles improves long-term bacterial viability and, consequently, provides efficient crack healing in biological concrete.
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17
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Hirose Y, Yamaguchi M, Sumitomo T, Nakata M, Hanada T, Okuzaki D, Motooka D, Mori Y, Kawasaki H, Coady A, Uchiyama S, Hiraoka M, Zurich RH, Amagai M, Nizet V, Kawabata S. Streptococcus pyogenes upregulates arginine catabolism to exert its pathogenesis on the skin surface. Cell Rep 2021; 34:108924. [PMID: 33789094 PMCID: PMC9214650 DOI: 10.1016/j.celrep.2021.108924] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 01/15/2021] [Accepted: 03/09/2021] [Indexed: 10/21/2022] Open
Abstract
The arginine deiminase (ADI) pathway has been found in many kinds of bacteria and functions to supplement energy production and provide protection against acid stress. The Streptococcus pyogenes ADI pathway is upregulated upon exposure to various environmental stresses, including glucose starvation. However, there are several unclear points about the advantages to the organism for upregulating arginine catabolism. We show that the ADI pathway contributes to bacterial viability and pathogenesis under low-glucose conditions. S. pyogenes changes global gene expression, including upregulation of virulence genes, by catabolizing arginine. In a murine model of epicutaneous infection, S. pyogenes uses the ADI pathway to augment its pathogenicity by increasing the expression of virulence genes, including those encoding the exotoxins. We also find that arginine from stratum-corneum-derived filaggrin is a key substrate for the ADI pathway. In summary, arginine is a nutrient source that promotes the pathogenicity of S. pyogenes on the skin.
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Affiliation(s)
- Yujiro Hirose
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA.
| | - Masaya Yamaguchi
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Tomoko Sumitomo
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8544, Japan
| | - Tomoki Hanada
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Daisuke Okuzaki
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Daisuke Motooka
- Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasushi Mori
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Hiroshi Kawasaki
- Department of Dermatology, Keio University School of Medicine, Tokyo 160-8582, Japan; Immunology Data Integration Unit, RIKEN Medical Sciences Innovation Hub Program, Yokohama 230-0045, Japan; Laboratory for Skin Homeostasis, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Alison Coady
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Satoshi Uchiyama
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Masanobu Hiraoka
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA; Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Wakayama 641-8509, Japan
| | - Raymond H Zurich
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Masayuki Amagai
- Department of Dermatology, Keio University School of Medicine, Tokyo 160-8582, Japan; Laboratory for Skin Homeostasis, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Victor Nizet
- Department of Pediatrics, University of California at San Diego School of Medicine, La Jolla, CA 92093, USA; Skaggs School of Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Shigetada Kawabata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
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18
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Chen SJ, Shu HY, Lin GH. Regulation of tert-Butyl Hydroperoxide Resistance by Chromosomal OhrR in A. baumannii ATCC 19606. Microorganisms 2021; 9:microorganisms9030629. [PMID: 33803549 PMCID: PMC8002998 DOI: 10.3390/microorganisms9030629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
In this study, we show that Acinetobacter baumannii ATCC 19606 harbors two sets of ohrR-ohr genes, respectively encoded in chromosomal DNA and a pMAC plasmid. We found no significant difference in organic hydroperoxide (OHP) resistance between strains with or without pMAC. However, a disk diffusion assay conducted by exposing wild-type, ∆ohrR-C, C represented gene on chromosome, or ∆ohr-C single mutants, or ∆ohrR-C∆ohr-C double mutants to tert-butyl hydroperoxide (tBHP) found that the ohrR-p-ohr-p genes, p represented genes on pMAC plasmid, may be able to complement the function of their chromosomal counterparts. Interestingly, ∆ohr-C single mutants generated in A. baumannii ATCC 17978, which does not harbor pMAC, demonstrated delayed exponential growth and loss of viability following exposure to 135 μg of tBHP. In a survival assay conducted with Galleria mellonella larvae, these mutants demonstrated almost complete loss of virulence. Via an electrophoretic mobility shift assay (EMSA), we found that OhrR-C was able to bind to the promoter regions of both chromosomal and pMAC ohr-p genes, but with varying affinity. A gain-of-function assay conducted in Escherichia coli showed that OhrR-C was not only capable of suppressing transformed ohr-C genes but may also repress endogenous enzymes. Taken together, our findings suggest that chromosomal ohrR-C-ohr-C genes act as the major system in protecting A. baumannii ATCC 19606 from OHP stresses, but the ohrR-p-ohr-p genes on pMAC can provide a supplementary protective effect, and the interaction between these genes may affect other aspects of bacterial viability, such as growth and virulence.
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Affiliation(s)
- Shih-Jie Chen
- Master Program in Microbiology and Immunology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan;
| | - Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan 71101, Taiwan;
| | - Guang-Huey Lin
- Master Program in Microbiology and Immunology, School of Medicine, Tzu Chi University, Hualien 97004, Taiwan;
- International College, Tzu Chi University, Hualien 97004, Taiwan
- Correspondence: or
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19
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Liu W, Li R, Deng F, Yan C, Zhou X, Miao L, Li X, Xu Z. A Cell Membrane Fluorogenic Probe for Gram-Positive Bacteria Imaging and Real-Time Tracking of Bacterial Viability. ACS Appl Bio Mater 2021; 4:2104-2112. [PMID: 35014338 DOI: 10.1021/acsabm.0c01269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bacterial infections are a global healthcare problem, resulting in serious clinical morbidities and mortality. Real-time monitoring of live bacteria by fluorescent imaging technology has potential in diagnosis of bacterial infections, elucidating antimicrobial agents' mode of action, assessing drug toxicity, and examining bacterial antimicrobial resistance. In this work, a naphthalimide-derived fluorescent probe ZTRS-BP was developed for wash-free Gram-positive bacteria imaging. The probe aggregated in aqueous solutions and exhibited aggregation-caused fluorescence quenching (ACQ). The interaction with Gram-positive bacteria cell walls would selectively disaggregate the probe and the liberated probes were dispersed on the outside of the bacteria cell walls to achieve surface fluorescence imaging. There were no such interactions with Gram-negative bacteria, which indicates that selective binding and imaging of Gram-positive bacteria was achieved. The binding of zinc ions by ZTRS-BP can enhance the fluorescent signals on the bacterial surface by inhibiting the process of photoinduced electron transfer. ZTRS-BP-Zn(II) complex was an excellent dye to discriminate mixed Gram-positive and Gram-negative bacteria. Also, live and dead bacteria can be differentially imaged by ZTRS-BP-Zn(II). Furthermore, ZTRS-BP-Zn(II) was used for real-time monitoring bacteria viability such as B. cereus treated with antibiotic vancomycin.
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Affiliation(s)
- Weiwei Liu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, China.,CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Ruihua Li
- The Second Affiliated Hospital of Dalian Medical University, Dalian 116023, China
| | - Fei Deng
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,School of Chemistry and Chemical Engineering, Jinggangshan University, Ji'an, Jiangxi 343009, China
| | - Chunyu Yan
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,Zhang Dayu Schoole of Chemistry, Dalian University of Technology, Dalian 116012, China
| | - Xuelian Zhou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,Zhang Dayu Schoole of Chemistry, Dalian University of Technology, Dalian 116012, China
| | - Lu Miao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiaolian Li
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, China
| | - Zhaochao Xu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, China.,CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,Zhang Dayu Schoole of Chemistry, Dalian University of Technology, Dalian 116012, China
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20
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Fleischmann S, Robben C, Alter T, Rossmanith P, Mester P. How to Evaluate Non-Growing Cells-Current Strategies for Determining Antimicrobial Resistance of VBNC Bacteria. Antibiotics (Basel) 2021; 10:115. [PMID: 33530321 DOI: 10.3390/antibiotics10020115] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022] Open
Abstract
Thanks to the achievements in sanitation, hygiene practices, and antibiotics, we have considerably improved in our ongoing battle against pathogenic bacteria. However, with our increasing knowledge about the complex bacterial lifestyles and cycles and their plethora of defense mechanisms, it is clear that the fight is far from over. One of these resistance mechanisms that has received increasing attention is the ability to enter a dormancy state termed viable but non-culturable (VBNC). Bacteria that enter the VBNC state, either through unfavorable environmental conditions or through potentially lethal stress, lose their ability to grow on standard enrichment media, but show a drastically increased tolerance against antimicrobials including antibiotics. The inability to utilize traditional culture-based methods represents a considerable experimental hurdle to investigate their increased antimicrobial resistance and impedes the development and evaluation of effective treatments or interventions against bacteria in the VBNC state. Although experimental approaches were developed to detect and quantify VBNCs, only a few have been utilized for antimicrobial resistance screening and this review aims to provide an overview of possible methodological approaches.
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21
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Moossavi S, Fontes ME, Rossi L, Fusch G, Surette MG, Azad MB. Capturing the diversity of the human milk microbiota through culture-enriched molecular profiling: a feasibility study. FEMS Microbiol Lett 2021; 368:6070652. [PMID: 33417698 DOI: 10.1093/femsle/fnab001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/05/2021] [Indexed: 12/19/2022] Open
Abstract
Previous human milk studies have confirmed the existence of a highly diverse bacterial community using culture-independent and targeted culture-dependent techniques. However, culture-enriched molecular profiling of milk microbiota has not been done. Additionally, the impact of storage conditions and milk fractionation on microbiota composition is not understood. In this feasibility study, we optimized and applied culture-enriched molecular profiling to study culturable milk microbiota in eight milk samples collected from mothers of infants admitted to a neonatal intensive care unit. Fresh samples were immediately plated or stored at -80°C for 2 weeks (short-term frozen). Long-term samples were stored at -20°C for >6 months. Samples were cultured using 10 different culture media and incubated both aerobically and anaerobically. We successfully isolated major milk bacteria, including Streptococcus, Staphylococcus and Bifidobacterium, from fresh milk samples, but were unable to culture any bacteria from the long-term frozen samples. Short-term freezing shifted the composition of viable milk bacteria from the original composition in fresh samples. Nevertheless, the inter-individual variability of milk microbiota composition was observed even after short-term storage. There was no major difference in the overall milk microbiota composition between milk fractions in this feasibility study. This is among the first studies on culture-enriched molecular profiling of the milk microbiota demonstrating the effect of storage and fractionation on milk microbiota composition.
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Affiliation(s)
- Shirin Moossavi
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.,Manitoba Interdisciplinary Lactation Centre (MILC), Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada.,Digestive Oncology Research Center, Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran 14117-13135, Iran.,Microbiome and Microbial Ecology Interest Group (MMEIG), Universal Scientific Education and Research Network (USERN), Calgary, AB T2N 4Z1, Canada
| | - Michelle E Fontes
- Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Laura Rossi
- Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Gerhard Fusch
- Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Michael G Surette
- Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada.,Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Meghan B Azad
- Manitoba Interdisciplinary Lactation Centre (MILC), Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada.,Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
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22
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Escudero-Sánchez R, Ponce-Alonso M, Barragán-Prada H, Morosini MI, Cantón R, Cobo J, del Campo R. Long-Term Impact of Suppressive Antibiotic Therapy on Intestinal Microbiota. Genes (Basel) 2020; 12:genes12010041. [PMID: 33396759 PMCID: PMC7823557 DOI: 10.3390/genes12010041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/20/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
The aim was to describe the safety of indefinite administration of antibiotics, the so-called suppressive antibiotic therapy (SAT) and to provide insight into their impact on gut microbiota. 17 patients with SAT were recruited, providing a fecal sample. Bacterial composition was determined by 16S rDNA massive sequencing, and their viability was explored by PCR-DGGE with and without propidium monoazide. Presence of antibiotic multirresistant bacteria was explored through the culture of feces in selective media. High intra-individual variability in the genera distribution regardless of the antibiotic or antibiotic administration ingestion period, with few statistically significant differences detected by Bray-Curtis distance-based principle component analysis, permutational multivariate analysis of variance and linear discriminant analysis effect size analysis. However, the microbiota composition of patients treated with both beta-lactams and sulfonamides clustered by a heat map. Curiously, the detection of antibiotic resistant bacteria was almost anecdotic and CTX-M-15-producing E. coli were detected in two subjects. Our work demonstrates the overall clinical safety of SAT and the low rate of the selection of multidrug-resistant bacteria triggered by this therapy. We also describe the composition of intestinal microbiota under the indefinite use of antibiotics for the first time.
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Affiliation(s)
- Rosa Escudero-Sánchez
- Servicio de Enfermedades Infecciosas, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (R.E.-S.); (J.C.)
| | - Manuel Ponce-Alonso
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (M.P.-A.); (M.I.M.); (R.C.)
| | - Hugo Barragán-Prada
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain;
| | - María Isabel Morosini
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (M.P.-A.); (M.I.M.); (R.C.)
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (M.P.-A.); (M.I.M.); (R.C.)
| | - Javier Cobo
- Servicio de Enfermedades Infecciosas, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (R.E.-S.); (J.C.)
| | - Rosa del Campo
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), and Red Española de Investigación en Patología Infecciosa (REIPI), 28034 Madrid, Spain; (M.P.-A.); (M.I.M.); (R.C.)
- Correspondence: ; Tel.: +34-913-368-832
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Chen Y, Caneli G, Almousa R, Hill K, Na S, Anderson GG, Xie D. A self-cured glass-ionomer cement with improved antibacterial function and hardness. POLYM ADVAN TECHNOL 2020; 31:3048-3058. [PMID: 35634167 PMCID: PMC9141094 DOI: 10.1002/pat.5029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/29/2020] [Indexed: 09/17/2023]
Abstract
A novel antimicrobial dental self-cured glass-ionomer cement has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial polymer and blended into a self-cured glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Results showed that the modified cements exhibited a significantly enhanced antibacterial activity along with improved surface hardness. Effects of antibacterial moiety content, alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate no cytotoxicity produced from the modified cements to both bacteria and 3T3 mouse fibroblast cells.
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Affiliation(s)
- Yong Chen
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
- Department of Materials Science, Jinchu University, Hubei, China
| | - Gulsah Caneli
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
| | - Rashed Almousa
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
| | - Kayla Hill
- Department of Biology, Purdue School of Science, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
| | - Sungsoo Na
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
| | - Gregory G. Anderson
- Department of Biology, Purdue School of Science, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
| | - Dong Xie
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana
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24
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Gómez-García M, Argüello H, Puente H, Mencía-Ares Ó, González S, Miranda R, Rubio P, Carvajal A. In-depth in vitro Evaluation of the Activity and Mechanisms of Action of Organic Acids and Essential Oils Against Swine Enteropathogenic Bacteria. Front Vet Sci 2020; 7:572947. [PMID: 33240953 PMCID: PMC7683615 DOI: 10.3389/fvets.2020.572947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/26/2020] [Indexed: 01/08/2023] Open
Abstract
Alternative antimicrobials require a deep understanding of their action mechanisms by in vitro assays which support science-based field use. This study focuses on the characterization of bactericidal mechanisms of potential antimicrobial compounds, two organic acids and three single essential oil (EO) compounds against swine enteropathogenic bacteria Escherichia coli, Salmonella enterica subsp. enterica serovar Typhimurium, and Clostridium perfringens. Target concentrations of the compounds were evaluated using the inhibitory potential of the vapor phase and bacterial viability after short-term exposure, while cell targets were disclosed using flow cytometry (FC), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). All tested compounds exhibited vapor phase activity against the three bacterial species, except sodium salt of coconut fatty acid distillates against C. perfringens. Survival test results evidenced that effects on bacterial viability were concentration dependent and higher in single EO compounds than in organic acids. In detail, thymol and its isomer carvacrol were the most effective compounds. Further characterization of thymol and cinnamaldehyde activity revealed that thymol main target was the cell membrane, since it caused striking damages in the membrane permeability, integrity and composition evidenced by FC and FTIR in the three enteric pathogens. In contrast, cinnamaldehyde was more effective against enterobacteria than against C. perfringens and only caused slightly damages at the highest concentration tested. Its target at the molecular level differed between enterobacteria and C. perfringens isolates. The SEM micrographs allowed us to confirm the results previously obtained for both EO compounds by other techniques. Altogether, the study showed the straight effect of these antimicrobials, which could constitute relevant information to optimize their feed inclusion rates in field studies or field use.
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Affiliation(s)
- Manuel Gómez-García
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Héctor Argüello
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Héctor Puente
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Óscar Mencía-Ares
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Sandra González
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Rubén Miranda
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Pedro Rubio
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
| | - Ana Carvajal
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad de León, León, Spain
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25
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Otero Fernandez M, Thomas RJ, Oswin H, Haddrell AE, Reid JP. Transformative Approach To Investigate the Microphysical Factors Influencing Airborne Transmission of Pathogens. Appl Environ Microbiol 2020; 86:e01543-20. [PMID: 32978136 PMCID: PMC7657628 DOI: 10.1128/aem.01543-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/17/2020] [Indexed: 01/06/2023] Open
Abstract
Emerging outbreaks of airborne pathogenic infections worldwide, such as the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, have raised the need to understand parameters affecting the airborne survival of microbes in order to develop measures for effective infection control. We report a novel experimental strategy, TAMBAS (tandem approach for microphysical and biological assessment of airborne microorganism survival), to explore the synergistic interactions between the physicochemical and biological processes that impact airborne microbe survival in aerosol droplets. This innovative approach provides a unique and detailed understanding of the processes taking place from aerosol droplet generation through to equilibration and viability decay in the local environment, elucidating decay mechanisms not previously described. The impact of evaporation kinetics, solute hygroscopicity and concentration, particle morphology, and equilibrium particle size on airborne survival are reported, using Escherichia coli MRE162 as a benchmark system. For this system, we report that (i) particle crystallization does not directly impact microbe longevity, (ii) bacteria act as crystallization nuclei during droplet drying and equilibration, and (iii) the kinetics of size and compositional change appear to have a larger effect on microbe longevity than the equilibrium solute concentration.IMPORTANCE A transformative approach to identify the physicochemical processes that impact the biological decay rates of bacteria in aerosol droplets is described. It is shown that the evaporation process and changes in the phase and morphology of the aerosol particle during evaporation impact microorganism viability. The equilibrium droplet size was found to affect airborne bacterial viability. Furthermore, the presence of Escherichia coli MRE162 in a droplet does not affect aerosol growth/evaporation but influences the dynamic behavior of the aerosol by processing the culture medium prior to aerosolization, affecting the hygroscopicity of the culture medium; this highlights the importance of the inorganic and organic chemical composition within the aerosolized droplets that impact hygroscopicity. Bacteria also act as crystallization nuclei. The novel approach and data have implications for increased mechanistic understanding of aerosol survival and infectivity in bioaerosol studies spanning the medical, veterinary, farming, and agricultural fields, including the role of microorganisms in atmospheric processing and cloud formation.
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Affiliation(s)
| | - Richard J Thomas
- Defence Science Technology Laboratory (DSTL), Porton Down, Salisbury, United Kingdom
| | - Henry Oswin
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Allen E Haddrell
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Bristol, United Kingdom
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26
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Wang M, Liu Q, Kang X, Zhu Z, Yang H, Xi X, Zhang X, Du Y, Guo M, Tang D, Wang L. Glycogen Metabolism Impairment via Single Gene Mutation in the glgBXCAP Operon Alters the Survival Rate of Escherichia coli Under Various Environmental Stresses. Front Microbiol 2020; 11:588099. [PMID: 33101261 PMCID: PMC7546213 DOI: 10.3389/fmicb.2020.588099] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
Glycogen is a highly branched polysaccharide that is widely present in all life domains. It has been identified in many bacterial species and functions as an important energy storage compound. In addition, it plays important roles in bacterial transmission, pathogenicity, and environmental viability. There are five essential enzymes (coding genes) directly involved in bacterial glycogen metabolism, which forms a single operon glgBXCAP with a suboperonic promoter in glgC gene in Escherichia coli. Currently, there is no comparative study of how the disruptions of the five glycogen metabolism genes influence bacterial phenotypes, such as growth rate, biofilm formation, and environmental survival, etc. In this study, we systematically and comparatively studied five E. coli single-gene mutants (ΔglgC, ΔglgA, ΔglgB, ΔglgP, ΔglgX) in terms of glycogen metabolism and explored their phenotype changes with a focus on environmental stress endurance, such as nutrient deprivation, low temperature, desiccation, and oxidation, etc. Biofilm formation in wild-type and mutant strains was also compared. E. coli wild-type stores the highest glycogen content after around 20-h culture while disruption of degradation genes (glgP, glgX) leads to continuous accumulation of glycogen. However, glycogen primary structure was abnormally changed in ΔglgP and ΔglgX. Meanwhile, increased accumulation of glycogen facilitates the growth of E. coli mutants but reduces glucose consumption in liquid culture and vice versa. Glycogen metabolism disruption also significantly and consistently increases biofilm formation in all the mutants. As for environmental stress endurance, glycogen over-accumulating mutants have enhanced starvation viability and reduced desiccation viability while all mutants showed decreased survival rate at low temperature. No consistent results were found for oxidative stress resistance in terms of glycogen metabolism disruptions, though ΔglgA shows highest resistance toward oxidation with unknown mechanisms. In sum, single gene disruptions in glgBXCAP operon significantly influence bacterial growth and glucose consumption during culture. Accumulation and structure of intracellular glycogen were also significantly altered. In addition, we observed significant changes in E. coli environmental viabilities due to the deletions of certain genes in the operon. Further investigations shall be focused on the molecular mechanisms behind these phenotype changes.
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Affiliation(s)
- Mengmeng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Qinghua Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xingxing Kang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Zuobin Zhu
- Department of Genetics, School of Life Sciences, Xuzhou Medical University, Xuzhou, China
| | - Huan Yang
- School of Laboratory Medicine, Xuzhou Medical University, Xuzhou, China
| | - Xiangyu Xi
- Xuzhou Infectious Disease Hospital, Xuzhou, China
| | - Xiao Zhang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Yan Du
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Mengzhe Guo
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Daoquan Tang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Liang Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
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27
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Park J, Lee Y, Hwang Y, Cho S. Interdigitated and Wave-Shaped Electrode-Based Capacitance Sensor for Monitoring Antibiotic Effects. Sensors (Basel) 2020; 20:E5237. [PMID: 32937982 DOI: 10.3390/s20185237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 12/26/2022]
Abstract
Label-free and real-time monitoring of the bacterial viability is essential for the accurate and sensitive characterization of the antibiotic effects. In the present study, we investigated the feasibility of the interdigitated and wave-shaped electrode (IWE) for monitoring the effect of tetracycline or kanamycin on Staphylococcus aureus (S. aureus) and methicillin-resistant S.aureus (MRSA). The electrical impedance spectra of the IWE immersed in the culture media for bacterial growth were characterized in a frequency range of 10 Hz to 1 kHz. The capacitance index (CI) (capacitance change relevant with the bacterial viability) was used to monitor the antibiotic effects on the S. aureus and MRSA in comparison to the traditional methods (disk diffusion test and optical density (OD) measurement). The experimental results showed that the percentage of change in CI (PCI) for the antibiotic effect on MRSA was increased by 51.58% and 57.83% in kanamycin and control, respectively. In contrast, the PCI value decreased by 0.25% for tetracycline, decreased by 52.63% and 37.66% in the cases of tetracycline and kanamycin-treated S. aureus, and increased 2.79% in the control, respectively. This study demonstrated the feasibility of the IWE-based capacitance sensor for the label-free and real-time monitoring of the antibiotic effects on S. aureus and MRSA.
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28
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Chen B, Zhao Y, Li Z, Pan J, Wu H, Qiu G, Feng C, Wei C. Immobilization of Phosphatidylserine by Ethanol and Lysozyme on the Cell Surface for Evaluation of Apoptosis-Like Decay in Activated-Sludge Bacteria. Appl Environ Microbiol 2020; 86:e00345-20. [PMID: 32414801 DOI: 10.1128/AEM.00345-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/30/2020] [Indexed: 01/18/2023] Open
Abstract
Accurate determination of microbial viability can be crucial in microbe-dominated biosystems. However, the identification of metabolic decay in bacterial cells can be elaborate and difficult. We sought to identify apoptosis-like bacterial processes by using annexin V-fluorescein isothiocyanate (FITC) (AVF), a probe typically used to stain phosphatidylserine (PS) on exposed cell membranes. The bacterial cell wall provides a barrier that is responsible for low efficiency of direct PS staining of decayed bacterial cells. This can be overcome by pretreatment of the bacteria with 70% ethanol, which fixates the bacteria and preserves the PS status, combined with lysozyme treatment to hydrolyze the cell wall. That treatment improved the efficiency of AVF staining considerably, as shown for pure strains of an Ochrobactrum sp. and a Micrococcus sp. Using this method, decayed bacterial cells (induced by starvation) were more strongly stained, indicating externalization of PS to a greater extent than seen for cells harvested at logarithmic growth. A multispecies microbial sludge was artificially decayed by heat treatment or alternating anoxic-oxic treatment, which also induced increased AVF staining, again presumably via decay-related PS externalization. The method developed proved to be efficient for identification of bacterial decay and has potential for the evaluation of multispecies bacterial samples from sources like soil matrix, bioaerosol, and activated sludge.IMPORTANCE Since the externalization of phosphatidylserine (PS) is considered a crucial characteristic of apoptosis, we sought to identify apoptosis-like decay in bacterial cells by PS staining using AVF. We show that this is possible, provided the bacteria are pretreated with ethanol plus lysozyme to remove a physical staining barrier and preserve the original, decay-related externalization of PS. Our work suggests that PS externalization occurs in starved bacteria and this can be quantified with AVF staining, providing a measure of bacterial decay. Since PS is the common component of the lipid bilayer in bacterial cell membranes, this approach also has potential for evaluation of cell decay of other bacterial species.
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29
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Leigh WJ, Zadoks RN, Costa JZ, Jaglarz A, Thompson KD. Development and evaluation of a quantitative polymerase chain reaction for aquatic Streptococcus agalactiae based on the groEL gene. J Appl Microbiol 2020; 129:63-74. [PMID: 31851413 DOI: 10.1111/jam.14556] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/23/2019] [Accepted: 12/08/2019] [Indexed: 01/19/2023]
Abstract
AIMS The aim of this study was to develop a TaqMan quantitative polymerase chain reaction (qPCR), based on the Streptococcus agalactiae groEL gene, to specifically quantify levels of bacteria within samples derived from aquatic sources, particularly aquaculture. Enumeration of bacteria by qPCR was compared with culture-based methods. METHODS AND RESULTS The qPCR was sensitive to 33 isolates of S. agalactiae, representing 11 clonal complexes from aquatic, bovine and human hosts. The specificity of the assay was 92·5% at a threshold Cq value of 35. No cross-reaction with Streptococcus iniae was noted and of the 22 comparator species screened to test assay specificity, Streptococcus porcinus had a Cq value of 33·7 S, while Streptococcus gallolyticus subsp. macedonicus and Streptococcus ictaluri had one replicate value above the Cq threshold of 35 (34·5 and 34·4 respectively), while only S. agalactiae were detected with a Cq value of 30. The limit of detection of the assay was 1·7 copies per µl at Cq 35. Discrepancies between molecular and culture-based methods of enumeration were noted. CONCLUSIONS The qPCR was able to detect a diverse range of S. agalactiae isolates from different clonal complexes (CCs) and could distinguish between S. agalactiae and closely related species, notably S. iniae. The results suggest that a Cq 30 would be a very meaningful cut-off, allowing the detection of infected fish while ruling out all false positives. SIGNIFICANCE AND IMPACT OF THE STUDY This rapid and sensitive qPCR assay is useful to quantify DNA copy number in the laboratory and could prove useful for detecting low levels of S. agalactiae in aquaculture systems, including Oreochromis niloticus culture.
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Affiliation(s)
- W J Leigh
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK.,Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - R N Zadoks
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK.,Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - J Z Costa
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - A Jaglarz
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - K D Thompson
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
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30
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Hasegawa T, Takenaka S, Wakamatsu R, Ohsumi T, Domon H, Ohshima H, Terao Y, Noiri Y. A Horizontal Sequential Cutting Method to Estimate the Effectiveness of Dentin Disinfection by Using Confocal Laser Scanning Microscopy. J Endod 2019; 45:1142-7. [PMID: 31376921 DOI: 10.1016/j.joen.2019.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 11/21/2022]
Abstract
INTRODUCTION This study aimed to develop a technique to create sequential slices, allowing the fluorescent visualization of bacterial viability in all parts of an infected dentin. METHODS Cylindrical dentin blocks were prepared from freshly extracted human teeth with a single-rooted canal. Each block was immersed in 5% sodium hypochlorite (NaOCl) and 17% EDTA for 5 minutes before being infected with Enterococcus faecalis. The bacteria were allowed to develop inside dentin specimens for 28 days under anaerobic conditions. The specimens were exposed in 2% NaOCl for either 2 minutes or 20 minutes at 20°C, 37°C, and 45°C, respectively. After staining with calcein AM (Thermo Fisher Scientific, Waltham, MA) and propidium iodide, the samples were cryoembedded, mounted on an adhesive film, and sectioned at a thickness of 10 μm along the running of the dentinal tubules. Stacks of fluorescent images were collected in the z dimension using confocal laser scanning microscopy, and the maximum affected distance from a root canal was measured from the 3-dimensional reconstructed image. The reliability of this technique was verified by comparison with a dye bleaching test. RESULTS Horizontal sequential sections preserving 3-dimensional bacterial distribution and their viabilities could be made without decalcification. The treatment time contributed to the penetration of NaOCl into dentinal tubules, whereas temperature did not significantly affect the penetration. The judgment by confocal laser scanning microscopic analysis was consistent with that of a dye bleaching test. CONCLUSIONS The horizontal sectioning method has the advantage of creating sequential sections, allowing information to be imaged at every portion.
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Alayande AB, Park HD, Vrouwenvelder JS, Kim IS. Implications of Chemical Reduction Using Hydriodic Acid on the Antimicrobial Properties of Graphene Oxide and Reduced Graphene Oxide Membranes. Small 2019; 15:e1901023. [PMID: 31148406 DOI: 10.1002/smll.201901023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/05/2019] [Indexed: 06/09/2023]
Abstract
The antimicrobial properties of graphene-based membranes such as single-layer graphene oxide (GO) and modified graphene oxide (rGO) on top of cellulose ester membrane are reported in this study. rGO membranes are made from GO by hydriodic acid (HI) vapor treatment. The antibacterial properties are tested after 3 h contact time with selected model bacteria. Complete bacterial cell inactivation is found only after contact with rGO membranes, while no significant bacterial inactivation is found for the control i) GO membrane, ii) the mixed cellulose ester support, and the iii) rGO membrane after additional washing that removes the remaining HI. This indicates that the antimicrobial effect is neither caused by the graphene nor the membrane support. The antimicrobial effect is found to be conclusively linked to the HI eliminating microbial growth, at concentrations from 0.005%. These findings emphasize the importance of caution in the reporting of antimicrobial properties of graphene-based surfaces.
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Affiliation(s)
- Abayomi Babatunde Alayande
- Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, South Korea
| | - Hee-Deung Park
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, 02841, South Korea
| | - Johannes S Vrouwenvelder
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - In S Kim
- Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, South Korea
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32
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Hu J, Ben Maamar S, Glawe AJ, Gottel N, Gilbert JA, Hartmann EM. Impacts of indoor surface finishes on bacterial viability. Indoor Air 2019; 29:551-562. [PMID: 30980566 PMCID: PMC6851865 DOI: 10.1111/ina.12558] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 05/21/2023]
Abstract
Microbes in indoor environments are constantly being exposed to antimicrobial surface finishes. Many are rendered non-viable after spending extended periods of time under low-moisture, low-nutrient surface conditions, regardless of whether those surfaces have been amended with antimicrobial chemicals. However, some microorganisms remain viable even after prolonged exposure to these hostile conditions. Work with specific model pathogens makes it difficult to draw general conclusions about how chemical and physical properties of surfaces affect microbes. Here, we explore the survival of a synthetic community of non-model microorganisms isolated from built environments following exposure to three chemically and physically distinct surface finishes. Our findings demonstrated the differences in bacterial survival associated with three chemically and physically distinct materials. Alkaline clay surfaces select for an alkaliphilic bacterium, Kocuria rosea, whereas acidic mold-resistant paint favors Bacillus timonensis, a Gram-negative spore-forming bacterium that also survives on antimicrobial surfaces after 24 hours of exposure. Additionally, antibiotic-resistant Pantoea allii did not exhibit prolonged retention on antimicrobial surfaces. Our controlled microcosm experiment integrates measurement of indoor chemistry and microbiology to elucidate the complex biochemical interactions that influence the indoor microbiome.
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Affiliation(s)
- Jinglin Hu
- Department of Civil and Environmental EngineeringNorthwestern UniversityEvanstonIllinois
| | - Sarah Ben Maamar
- Department of Civil and Environmental EngineeringNorthwestern UniversityEvanstonIllinois
| | - Adam J. Glawe
- Department of Civil and Environmental EngineeringNorthwestern UniversityEvanstonIllinois
| | - Neil Gottel
- Department of SurgeryThe University of ChicagoChicagoIllinois
| | - Jack A. Gilbert
- Department of SurgeryThe University of ChicagoChicagoIllinois
| | - Erica M. Hartmann
- Department of Civil and Environmental EngineeringNorthwestern UniversityEvanstonIllinois
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Xie D, Howard L, Almousa R. Surface modification of polyurethane with a hydrophilic, antibacterial polymer for improved antifouling and antibacterial function. J Biomater Appl 2018; 33:340-351. [PMID: 30089433 DOI: 10.1177/0885328218792687] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antimicrobial surface is important for the inhibition of bacteria or biofilm formation on biomaterials. The objective of this study was to immobilize a novel hydrophilic polymer containing the antibacterial moiety onto polyurethane surface via a simple surface coating technology to make the surface not only antibacterial but also antifouling. The compound 3,4-dichloro-5-hydroxy-2(5H)-furanone was derivatized, characterized and incorporated onto polyvinylpyrrolidone containing succinimidyl functional groups, followed by coating onto the polyurethane surface. Contact angle, antibacterial function and protein adsorption of the modified surface were evaluated. The result shows that the modified surface exhibited significantly enhanced hydrophilicity with a 54-65% decrease in contact angle, increased antibacterial activity to Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa with a 24-57% decrease in viability, and reduced human serum albumin adsorption with a 64-70% decrease in adsorption, as compared to the original polyurethane.
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Affiliation(s)
- Dong Xie
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis 46202, IN, USA
| | - Leah Howard
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis 46202, IN, USA
| | - Rashed Almousa
- Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University at Indianapolis, Indianapolis 46202, IN, USA
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Wietzikoski Lovato EC, Gurgel Velasquez PA, Dos Santos Oliveira C, Baruffi C, Anghinoni T, Machado RC, Lívero FADR, Sato SW, Martins LDA. High frequency equipment promotes antibacterial effects dependent on intensity and exposure time. Clin Cosmet Investig Dermatol 2018; 11:131-135. [PMID: 29606883 PMCID: PMC5868622 DOI: 10.2147/ccid.s156282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background The indiscriminate use of antibiotics has caused bacteria to develop mechanisms of resistance to antibacterial agents, limiting treatment options. Therefore, there is a great need for alternative methods to control infections, especially those related to skin. One of the alternative methods is the high frequency equipment (HFE), which is used on skin conditions as an analgesic, an anti-inflammatory, and mainly to accelerate cicatricial processes and have a bactericidal effect through the formation of ozone. This research investigated the antibacterial effect of HFE on standard cultures of bacteria. Materials and methods Dilutions (104 colony forming unit mL−1) were performed for Enterobacter aerogenes and Staphylococcus aureus with 24-hour growth bacteria. Then, 1 μL of each dilution was pipetted into suitable medium and the HFE flashing technique was used at intensities of 6, 8 and 10 mA for 30, 60, 90, 120 and 180 seconds. The control group received no treatment. Plates were incubated at 37°C for 24 hours and then read. Results The spark at intensity of 6 mA had no bactericidal effect on the E. aerogenes; however, a significant bacterial growth reduction occurred at intensity of 8 mA after 120 and 180 seconds, and at 10 mA, reduction in bacterial growth could already be verified at 30 seconds and total bacterial growth inhibition occurred in 180 seconds. For S. aureus, there was a strong bacterial growth inhibition at all intensities used; however, at 6 mA, absence of bacterium growth after 120 and 180 seconds was observed. By increasing the flashing intensity to 8 and 10 mA, it was observed that the bacterium growth was inhibited after only 30 seconds of irradiation. Conclusion The HFE has time-dependent antibacterial effects against E. aerogenes and S. aureus bacteria that have several resistance mechanisms.
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Affiliation(s)
| | | | | | - Camila Baruffi
- Laboratory of Microbiology of Natural Products, Paranaense University, Umuarama, Brazil
| | - Thais Anghinoni
- Laboratory of Microbiology of Natural Products, Paranaense University, Umuarama, Brazil
| | - Raquel Costa Machado
- Laboratory of Microbiology of Natural Products, Paranaense University, Umuarama, Brazil
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Syal K, Shen S, Yang Y, Wang S, Haydel SE, Tao N. Rapid Antibiotic Susceptibility Testing of Uropathogenic E. coli by Tracking Submicron Scale Motion of Single Bacterial Cells. ACS Sens 2017; 2:1231-1239. [PMID: 28741927 DOI: 10.1021/acssensors.7b00392] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
To combat antibiotic resistance, a rapid antibiotic susceptibility testing (AST) technology that can identify resistant infections at disease onset is required. Current clinical AST technologies take 1-3 days, which is often too slow for accurate treatment. Here we demonstrate a rapid AST method by tracking sub-μm scale bacterial motion with an optical imaging and tracking technique. We apply the method to clinically relevant bacterial pathogens, Escherichia coli O157: H7 and uropathogenic E. coli (UPEC) loosely tethered to a glass surface. By analyzing dose-dependent sub-μm motion changes in a population of bacterial cells, we obtain the minimum bactericidal concentration within 2 h using human urine samples spiked with UPEC. We validate the AST method using the standard culture-based AST methods. In addition to population studies, the method allows single cell analysis, which can identify subpopulations of resistance strains within a sample.
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Affiliation(s)
- Karan Syal
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Simon Shen
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Yunze Yang
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Shaopeng Wang
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Shelley E. Haydel
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Nongjian Tao
- Biodesign Center for Biosensors and
Bioelectronics, ‡School of Electrical, Computer and
Energy Engineering, §Biodesign Center for Immunotherapy, Vaccines, and Virotherapy, and ∥School of Life
Sciences, Arizona State University, Tempe, Arizona 85287, United States
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Rodriguez-Rodrigues N, Castillo LA, Landoni VI, Martire-Greco D, Milillo MA, Barrionuevo P, Fernández GC. Prokaryotic RNA Associated to Bacterial Viability Induces Polymorphonuclear Neutrophil Activation. Front Cell Infect Microbiol 2017; 7:306. [PMID: 28730145 PMCID: PMC5498479 DOI: 10.3389/fcimb.2017.00306] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/20/2017] [Indexed: 11/13/2022] Open
Abstract
Polymorphonuclear neutrophils (PMN) are the first cellular line of antibacterial host defense. They sense pathogens through recognition of pathogen-associated molecular patterns (PAMPs) by innate pattern recognition receptors, such as Toll-like receptors (TLR). The aim of this study was to investigate whether PMN sense bacterial viability and explore which viability factor could be involved in this phenomenon. For this purpose, different functions were evaluated in isolated human PMN using live Escherichia coli (Ec) and heat-killed Ec (HK-Ec). We found that bacterial viability was indispensable to induce PMN activation, as measured by forward-scatter (FSC) increase, CD11b surface expression, chemotaxis, reactive oxygen species (ROS) generation and neutrophil extracellular trap (NET) formation. As uncapped non-polyadenylated prokaryotic mRNA has been recognized as a PAMP associated to bacterial viability by macrophages and dendritic cells, total prokaryotic RNA (pRNA) from live Ec was purified and used as a stimulus for PMN. pRNA triggered similar responses to those observed with live bacteria. No RNA could be isolated from HK-Ec, explaining the lack of effect of dead bacteria. Moreover, the supernatant of dead bacteria was able to induce PMN activation, and this was associated with the presence of pRNA in this supernatant, which is released in the killing process. The induction of bactericidal functions (ROS and NETosis) by pRNA were abolished when the supernatant of dead bacteria or isolated pRNA were treated with RNAse. Moreover, endocytosis was necessary for pRNA-induced ROS generation and NETosis, and priming was required for the induction of pRNA-induced ROS in whole blood. However, responses related to movement and degranulation (FSC increase, CD11b up-regulation, and chemotaxis) were still triggered when pRNA was digested with RNase, and were not dependent on pRNA endocytosis or PMN priming. In conclusion, our results indicate that PMN sense live bacteria through recognition of pRNA, and this sensing triggers potent bactericidal mechanisms.
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Affiliation(s)
- Nahuel Rodriguez-Rodrigues
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - Luis A Castillo
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - Verónica I Landoni
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - Daiana Martire-Greco
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - M Ayelén Milillo
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - Paula Barrionuevo
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
| | - Gabriela C Fernández
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental CONICET, Academia Nacional de MedicinaBuenos Aires, Argentina
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Hann SD, Niepa THR, Stebe KJ, Lee D. One-Step Generation of Cell-Encapsulating Compartments via Polyelectrolyte Complexation in an Aqueous Two Phase System. ACS Appl Mater Interfaces 2016; 8:25603-11. [PMID: 27580225 DOI: 10.1021/acsami.6b07939] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Diverse fields including drug and gene delivery and live cell encapsulation require biologically compatible encapsulation systems. One widely adopted means of forming capsules exploits cargo-filled microdroplets in an external, immiscible liquid phase that are encapsulated by a membrane that forms by trapping of molecules or particles at the drop surface, facilitated by the interfacial tension. To eliminate the potentially deleterious oil phase often present in such processes, we exploit the aqueous two phase system of poly(ethylene glycol) (PEG) and dextran. We form capsules by placing dextran-rich microdroplets in an external PEG-rich phase. Strong polyelectrolytes present in either phase form complexes at the drop interface, thereby forming a membrane encapsulating the fluid interior. This process requires considerable finesse as both polyelectrolytes are soluble in either the drop or external phase, and the extremely low interfacial tension is too weak to provide a strong adsorption site for these molecules. The key to obtaining microcapsules is to tune the relative fluxes of the two polyelectrolytes so that they meet and complex at the interface. We identify conditions for which complexation can occur inside or outside of the drop phase, resulting in microparticles or poor encapsulation, respectively, or when properly balanced, at the interface, resulting in microcapsules. The resulting microcapsules respond to the stimuli of added salts or changes in osmotic pressure, allowing perturbation of capsule permeability or triggered release of capsule contents. We demonstrate that living cells can be sequestered and interrogated by encapsulating Pseudomonas aeruginosa PAO1 and using a Live/Dead assay to assess their viability. This method paves the way to the formation of a broad variety of versatile functional membranes around all aqueous capsules; by tuning the fluxes of complexing species to interact at the interface, membranes comprising other complexing functional moieties can be formed.
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Affiliation(s)
- Sarah D Hann
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Tagbo H R Niepa
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Kathleen J Stebe
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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38
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Esteves AIS, Amer N, Nguyen M, Thomas T. Sample Processing Impacts the Viability and Cultivability of the Sponge Microbiome. Front Microbiol 2016; 7:499. [PMID: 27242673 PMCID: PMC4876369 DOI: 10.3389/fmicb.2016.00499] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/28/2016] [Indexed: 12/17/2022] Open
Abstract
Sponges host complex microbial communities of recognized ecological and biotechnological importance. Extensive cultivation efforts have been made to isolate sponge bacteria, but most still elude cultivation. To identify the bottlenecks of sponge bacterial cultivation, we combined high-throughput 16S rRNA gene sequencing with a variety of cultivation media and incubation conditions. We aimed to determine the extent to which sample processing and cultivation conditions can impact bacterial viability and recovery in culture. We isolated 325 sponge bacteria from six specimens of Cymbastela concentrica and three specimens of Scopalina sp. These isolates were distributed over 37 different genera and 47 operational taxonomic units (defined at 97% 16S rRNA gene sequence identity). The cultivable bacterial community was highly specific to its sponge host and different media compositions yielded distinct microbial isolates. Around 97% of the isolates could be detected in the original sponge and represented a large but highly variable proportion (0.5–92% total abundance, depending on sponge species) of viable bacteria obtained after sample processing, as determined by propidium monoazide selective DNA modification of compromised cells. Our results show that the most abundant viable bacteria are also the most predominant groups found in cultivation, reflecting, to some extent, the relative abundances of the viable bacterial community, rather than the overall community estimated by direct molecular approaches. Cultivation is therefore shaped not only by the growth conditions provided, but also by the different cell viabilities of the bacteria that constitute the cultivation inoculum. These observations highlight the need to perform experiments to assess each method of sample processing for its accurate representation of the actual in situ bacterial community and its yield of viable cells.
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Affiliation(s)
- Ana I S Esteves
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Nimra Amer
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Mary Nguyen
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Torsten Thomas
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
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39
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Park HJ, Lee GH, Jun J, Son M, Kang MJ. Multiple-unit tablet of probiotic bacteria for improved storage stability, acid tolerability, and in vivo intestinal protective effect. Drug Des Devel Ther 2016; 10:1355-64. [PMID: 27103789 PMCID: PMC4827893 DOI: 10.2147/dddt.s103894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this study was to formulate probiotics-loaded pellets in a tablet form to improve storage stability, acid tolerability, and in vivo intestinal protective effect. Bacteria-loaded pellets primarily prepared with hydroxypropyl methylcellulose acetate succinate were compressed into tablets with highly compressible excipients and optimized for flow properties, hardness, and disintegration time. The optimized probiotic tablet consisted of enteric-coated pellets (335 mg), microcrystalline cellulose (Avicel PH102, 37.5 mg), and porous calcium silicate (25 mg) and allowed whole survival of living bacteria during the compaction process with sufficient tablet hardness (13 kp) and disintegration time (14 minutes). The multiple-unit tablet showed remarkably higher storage stability under ambient conditions (25°C/60% relative humidity) over 6 months and resistance to acidic medium compared to uncoated strains or pellets. Repeated intake of this multiple-unit tablet significantly lowered plasma level of endotoxin, a pathogenic material, compared to repeated intake of bare probiotics or marketed products in rats. These results, therefore, suggest that the multiple-unit tablet is advantageous to better bacterial viability and gain the beneficial effects on the gut flora, including the improvement of intestinal barrier function.
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Affiliation(s)
- Hee Jun Park
- Dong-A Pharmaceutical Co. Ltd., Yongin, Gyeonggi, Korea
| | - Ga Hyeon Lee
- Dong-A Pharmaceutical Co. Ltd., Yongin, Gyeonggi, Korea
| | - Joonho Jun
- Dong-A Pharmaceutical Co. Ltd., Yongin, Gyeonggi, Korea
| | - Miwon Son
- Dong-A Pharmaceutical Co. Ltd., Yongin, Gyeonggi, Korea
| | - Myung Joo Kang
- College of Pharmacy, Dankook University, Cheonan, Chungnam, Korea
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40
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Wu S, Yang T, Luo Y, Li X, Zhang X, Tang J, Ma X, Wang Z. Efficacy of the novel oxazolidinone compound FYL-67 for preventing biofilm formation by Staphylococcus aureus. J Antimicrob Chemother 2014; 69:3011-9. [PMID: 24997316 DOI: 10.1093/jac/dku240] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES Infections of hospitalized patients caused by biofilms formed by Staphylococcus aureus represent a major problem. Using in vitro and in vivo biofilm models, we evaluated the efficacy of the novel oxazolidinone FYL-67, by using linezolid (the only clinically approved oxazolidinone antibiotic) as a control, for inhibiting S. aureus biofilm formation. METHODS Antibiofilm activity was determined using strains of methicillin-susceptible S. aureus and methicillin-resistant S. aureus. We studied the mechanism(s) and pharmacodynamics of antibiofilm activity as follows: (i) effects of pre- and post-exposure to FYL-67 or linezolid on biofilm formation; (ii) the effect of FYL-67 on biofilm structure; (iii) the role of FYL-67 in biofilm composition; (iv) effects on cell morphology; and (v) efficacy of FYL-67 and linezolid using an in vivo murine model of catheter infection. RESULTS FYL-67 effectively inhibited biofilm formation using in vitro and in vivo assays. CONCLUSIONS Our data suggest that oxazolidinone compounds, such as FYL-67, may serve as antibiofilm agents.
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Affiliation(s)
- Sisi Wu
- Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tao Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xiaolu Li
- Institute of Burn Research, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Xian Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jianying Tang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xiuying Ma
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Zhenling Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
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Tavares A, Carvalho CMB, Faustino MA, Neves MGPMS, Tomé JPC, Tomé AC, Cavaleiro JAS, Cunha Â, Gomes NCM, Alves E, Almeida A. Antimicrobial photodynamic therapy: study of bacterial recovery viability and potential development of resistance after treatment. Mar Drugs 2010; 8:91-105. [PMID: 20161973 PMCID: PMC2817925 DOI: 10.3390/md8010091] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/06/2010] [Accepted: 01/19/2010] [Indexed: 12/27/2022] Open
Abstract
Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py(+)-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py(+)-Me-PF (5.0 microM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m(-2)) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 microM of Tri-Py(+)-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py(+)-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process.
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Affiliation(s)
- Anabela Tavares
- CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(A.T.);
(A.C.);
(N.C.M.G.);
(E.A.)
| | - Carla M. B. Carvalho
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
| | - Maria A. Faustino
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
| | - Maria G. P. M. S. Neves
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
- * Authors to whom correspondence should be addressed; E-Mails:
(A.A.);
(M.G.P.M.S.N.); Tel.: +351 234 370784; +351 234 370713
| | - João P. C. Tomé
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
| | - Augusto C. Tomé
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
| | - José A. S. Cavaleiro
- QOPNA and Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(C.M.B.C.);
(M.A.F.);
(J.P.C.T.);
(A.C.T.);
(J.A.S.C.)
| | - Ângela Cunha
- CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(A.T.);
(A.C.);
(N.C.M.G.);
(E.A.)
| | - Newton C. M. Gomes
- CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(A.T.);
(A.C.);
(N.C.M.G.);
(E.A.)
| | - Eliana Alves
- CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(A.T.);
(A.C.);
(N.C.M.G.);
(E.A.)
| | - Adelaide Almeida
- CESAM and Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; E-Mails:
(A.T.);
(A.C.);
(N.C.M.G.);
(E.A.)
- * Authors to whom correspondence should be addressed; E-Mails:
(A.A.);
(M.G.P.M.S.N.); Tel.: +351 234 370784; +351 234 370713
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