101
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Copin S, Mougin J, Raguenet V, Robert-Pillot A, Midelet G, Grard T, Bonnin-Jusserand M. Ethidium and propidium monoazide: comparison of potential toxicity on Vibrio sp. viability. Lett Appl Microbiol 2020; 72:245-250. [PMID: 33058219 DOI: 10.1111/lam.13412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 11/29/2022]
Abstract
Vibrio sp., ubiquitous in the aquatic ecosystem, are bacteria of interest because of their involvement in human health, causing gastroenteritis after ingestion of seafood, as well as their role in vibriosis leading to severe losses in aquaculture production. Their ability to enter a viable but non-culturable (VBNC) state under stressful environmental conditions may lead to underestimation of the Vibrio population by traditional microbiological enumeration methods. As a result, using molecular methods in combination with EMA or PMA allows the detection of viable (VBNC and culturable viable) cells. In this study, the impact of the EMA and PMA was tested at different concentrations on the viability of several Vibrio species. We compared the toxicity of these two DNA-binding dyes to determine the best pretreatment to use with qPCR to discriminate between viable and dead Vibrio cells. Our results showed that EMA displayed lethal effects for each strain of V. cholerae and V. vulnificus tested. In contrast, the concentrations of PMA tested had no toxic effect on the viability of Vibrio cells studied. These results may help to achieve optimal PMA-qPCR methods to detect viable Vibrio sp. cells in food and environmental samples.
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Affiliation(s)
- S Copin
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - J Mougin
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
| | - V Raguenet
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - A Robert-Pillot
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Centre National de Référence des Vibrions et du Choléra, Paris, France
| | - G Midelet
- Agence Nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Laboratoire de sécurité des aliments, Boulogne-sur-Mer, France
| | - T Grard
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
| | - M Bonnin-Jusserand
- Institut Charles Viollette, Univ. Littoral Côte d'Opale, UMR 1158 BioEcoAgro, USC ANSES, INRAE, Univ. Lille, Univ. Artois, Univ. Picardie Jules Verne, Univ. Liège, Yncréa, Boulogne-sur-Mer, France
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102
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Xue J, Zhang B, Lamori J, Shah K, Zabaleta J, Garai J, Taylor CM, Sherchan SP. Molecular detection of opportunistic pathogens and insights into microbial diversity in private well water and premise plumbing. JOURNAL OF WATER AND HEALTH 2020; 18:820-834. [PMID: 33095203 PMCID: PMC9115838 DOI: 10.2166/wh.2020.271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Private well water systems in rural areas that are improperly maintained will result in poor drinking water quality, loss of water supply, and pose human health risk. The purpose of this study was to investigate the occurrence of fecal indicator bacteria (FIB) and opportunistic pathogens in private well water in rural areas surrounding New Orleans, Louisiana. Our results confirmed the ubiquitous nature of Legionella (86.7%) and mycobacteria (68.1%) in private well water in the study area, with gene concentration ranged from 0.60 to 5.53 and 0.67 to 5.95 Log10 of GC/100 mL, respectively. Naegleria fowleri target sequence was detected in 16.8% and Escherichia coli was detected in 43.4% of the water samples. Total coliform, as well as Legionella and mycobacteria genetic markers' concentrations were significantly reduced by 3-minute flushing. Next-generation sequencing (NGS) data indicated that the abundance of bacterial species was significantly increased in water collected in kitchens compared with samples from wells directly. This study provided integrated knowledge on the persistence of pathogenic organisms in private well water. Further study is needed to explore the presence of clinical species of those opportunistic pathogens in private well water systems to elucidate the health risk.
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Affiliation(s)
- Jia Xue
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Bowen Zhang
- Department of Natural Resources and Environmental Management, Ball State University, Muncie, Indiana, 47306, USA
| | - Jennifer Lamori
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Kinjal Shah
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
| | - Jovanny Zabaleta
- Department of Pediatrics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, 70112, USA
| | - Jone Garai
- Department of Pediatrics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, 70112, USA
| | - Christopher M Taylor
- Department of Microbiology, Immunology & Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, 70112, USA
| | - Samendra P Sherchan
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, 70112, USA E-mail:
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103
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Screening for heat-resistant reference yeast isolate in orange juice. Food Microbiol 2020; 94:103639. [PMID: 33279065 DOI: 10.1016/j.fm.2020.103639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/25/2020] [Accepted: 08/29/2020] [Indexed: 11/23/2022]
Abstract
This study details a screening process for yeast species that may be used as reference microorganisms for mild thermal processing of orange juice. In the initial step, 17 different strains of spoilage yeasts with similar initial populations (6.0-7.0 log CFU/mL) and growth stage (middle stationary phase) were subjected to equal heating process (55 °C, 5 min) in Yeast Peptone Glucose Broth (pH 6.06). The change in populations observed ranged from 3.33 log CFU/mL (Pichia fermentans BFE-38) to 6.53 log CFU/mL (Torulaspora delbrueckii BFE-37). In the second step of the screening, 6 of the most resistant strains were further challenged in an orange juice suspending medium (pH 3.88, 10.02 °Brix, 0.82% citric acid) at different heating temperatures (50, 53, 55, 57, and 60 °C). The decimal reduction times (DT values) and thermal resistant constants (z values) were determined. Results showed that all tested yeasts exhibited first-order, log-linear inactivation behavior (R2 0.90-0.99). As expected, significant (P < 0.05) reduction in the DT values were observed with increasing temperature. P. fermentans BFE-38 exhibited the greatest Dvalues at 50-55 °C. However, the test isolate with the greatest z-value was found to be P. anomala (BIOTECH 2205).
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104
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Kreth J, Merritt J, Pfeifer C, Khajotia S, Ferracane J. Interaction between the Oral Microbiome and Dental Composite Biomaterials: Where We Are and Where We Should Go. J Dent Res 2020; 99:1140-1149. [PMID: 32479134 PMCID: PMC7443996 DOI: 10.1177/0022034520927690] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dental composites are routinely placed as part of tooth restoration procedures. The integrity of the restoration is constantly challenged by the metabolic activities of the oral microbiome. This activity directly contributes to a less-than-desirable half-life for the dental composite formulations currently in use. Therefore, many new antimicrobial dental composites are being developed to counteract the microbial challenge. To ensure that these materials will resist microbiome-derived degradation, the model systems used for testing antimicrobial activities should be relevant to the in vivo environment. Here, we summarize the key steps in oral microbial colonization that should be considered in clinically relevant model systems. Oral microbial colonization is a clearly defined developmental process that starts with the formation of the acquired salivary pellicle on the tooth surface, a conditioned film that provides the critical attachment sites for the initial colonizers. Further development includes the integration of additional species and the formation of a diverse, polymicrobial mature biofilm. Biofilm development is discussed in the context of dental composites, and recent research is highlighted regarding the effect of antimicrobial composites on the composition of the oral microbiome. Future challenges are addressed, including the potential of antimicrobial resistance development and how this could be counteracted by detailed studies of microbiome composition and gene expression on dental composites. Ultimately, progress in this area will require interdisciplinary approaches to effectively mitigate the inevitable challenges that arise as new experimental bioactive composites are evaluated for potential clinical efficacy. Success in this area could have the added benefit of inspiring other fields in medically relevant materials research, since microbial colonization of medical implants and devices is a ubiquitous problem in the field.
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Affiliation(s)
- J. Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - J. Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - C.S. Pfeifer
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - S. Khajotia
- Department of Restorative Sciences, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - J.L. Ferracane
- Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
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105
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Lv X, Wang L, Zhang J, Zeng H, Chen X, Shi L, Cui H, He X, Zhao L. Rapid and sensitive detection of VBNC Escherichia coli O157: H7 in beef by PMAxx and real-time LAMP. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107292] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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106
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Margiotta F, Balestra C, Buondonno A, Casotti R, D'Ambra I, Di Capua I, Gallia R, Mazzocchi MG, Merquiol L, Pepi M, Percopo I, Saggiomo M, Sarno D, Zingone A. Do plankton reflect the environmental quality status? The case of a post-industrial Mediterranean Bay. MARINE ENVIRONMENTAL RESEARCH 2020; 160:104980. [PMID: 32907718 DOI: 10.1016/j.marenvres.2020.104980] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
While the effects of industrial contamination in coastal areas may persist for years in benthos communities, plankton should not show permanent impairments because of their high spatial dynamics, fast turnover times and pronounced seasonality. To test this hypothesis, in 2019 we conducted five surveys in the Bay of Pozzuoli (Gulf of Naples, Mediterranean Sea), in front of a dismissed steel factory and in the adjacent inshore coastal waters. High seasonal variability was observed for bacteria, phytoplankton and mesozooplankton, whereas plankton spatial gradients were relatively smooth during each survey. Plankton biomass and diversity did not reveal any effects of past industrial activities not even at the innermost stations of the Bay, which however showed some signals of present anthropogenic pressure. Hydrodynamic and morphological features likely play a prominent role in maintaining a relatively good status of the plankton of the Bay, which hints at the relevance of coastal circulation and meteorological dynamics to revitalize areas impacted by human activities.
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Affiliation(s)
| | - Cecilia Balestra
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Angela Buondonno
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Raffaella Casotti
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Isabella D'Ambra
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Iole Di Capua
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Roberto Gallia
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | | | - Louise Merquiol
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Milva Pepi
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Isabella Percopo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Maria Saggiomo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Diana Sarno
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Adriana Zingone
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
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107
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Khezri M, Rezaei M, Mohabbati Mobarez A, Zolfaghari M. Viable but non culturable state and expression of pathogenic genes of
Escherichia coli
O157
:
H7
in salted silver carp. J Food Saf 2020. [DOI: 10.1111/jfs.12843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammad Khezri
- Department of Seafood Processing, Faculty of Marine Sciences Tarbiat Modares University Noor Iran
| | - Masoud Rezaei
- Department of Seafood Processing, Faculty of Marine Sciences Tarbiat Modares University Noor Iran
| | | | - Mehdi Zolfaghari
- Faculty of Fisheries and Environmental Sciences Agricultur and Natural Resource University of Gorgan Gorgan Iran
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108
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Baccari O, Elleuch J, Barkallah M, Boukedi H, Ayed NB, Hammami A, Fendri I, Abdelkafi S. Development of a new TaqMan-based PCR assay for the specific detection and quantification of Simkania negevensis. Mol Cell Probes 2020; 53:101645. [PMID: 32745685 DOI: 10.1016/j.mcp.2020.101645] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/02/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Simkania negevensis is an emerging Chlamydia-like bacterium related to human respiratory diseases. An early and accurate detection of this pathogen could be useful to monitor the potential infectious risks and to set suitable outbreak control measures. In Tunisia, distribution and abundance of S. negevensis remain until now largely unknown. In the present work, a qPCR assay, targeting the 16S rRNA gene, for fast detection and quantification of S. negevensis was developed and validated. A high specificity for S. negevensis detection displaying no cross-reaction with the closely related Chlamydia spp. or the other tested microorganisms was noticed. qPCR assay performance was considered very satisfying with detection limits of 5 DNA copies per reaction. qPCR assay validation was performed by screening 37 clinical specimens and 35 water samples. S. negevensis wasn't detected in respiratory samples, but it was found in four cases of water samples. We suggest that the qPCR assay developed in this study could be considered sufficiently characterized to initiate the quantification of S. negevensis in environmental samples.
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Affiliation(s)
- Olfa Baccari
- Laboratoire de Génie Enzymatique et Microbiologie, Equipe Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Sfax, Tunisia
| | - Jihen Elleuch
- Laboratoire de Génie Enzymatique et Microbiologie, Equipe Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Sfax, Tunisia.
| | - Mohamed Barkallah
- Laboratoire de Génie Enzymatique et Microbiologie, Equipe Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Sfax, Tunisia
| | - Hanen Boukedi
- Laboratory of Biopesticides, Biotechnology Center of Sfax, University of Sfax, Sfax, Tunisia
| | - Nourelhouda Ben Ayed
- Laboratory of Microbiology, Faculty of Medicine of Sfax, Habib Bourguiba University Hospital, University of Sfax, Tunisia
| | - Adnene Hammami
- Laboratory of Microbiology, Faculty of Medicine of Sfax, Habib Bourguiba University Hospital, University of Sfax, Tunisia
| | - Imen Fendri
- Laboratory of Plant Biotechnology Applied to the Improvement of Cultures, Faculty of Science of Sfax, Tunisia
| | - Slim Abdelkafi
- Laboratoire de Génie Enzymatique et Microbiologie, Equipe Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Sfax, Tunisia
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109
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Ríos-Castillo A, Ripolles-Avila C, Rodríguez-Jerez J. Detection of Salmonella Typhimurium and Listeria monocytogenes biofilm cells exposed to different drying and pre-enrichment times using conventional and rapid methods. Int J Food Microbiol 2020; 324:108611. [DOI: 10.1016/j.ijfoodmicro.2020.108611] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/28/2023]
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110
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Taher E, Hemmatzadeh F, Aly S, Elesswy H, Petrovski K. Survival of staphylococci and transmissibility of their antimicrobial resistance genes in milk after heat treatments. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109584] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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111
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Pang S, Lin Z, Zhang W, Mishra S, Bhatt P, Chen S. Insights Into the Microbial Degradation and Biochemical Mechanisms of Neonicotinoids. Front Microbiol 2020; 11:868. [PMID: 32508767 PMCID: PMC7248232 DOI: 10.3389/fmicb.2020.00868] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/14/2020] [Indexed: 12/22/2022] Open
Abstract
Neonicotinoids are derivatives of synthetic nicotinoids with better insecticidal capabilities, including imidacloprid, nitenpyram, acetamiprid, thiacloprid, thiamethoxam, clothianidin, and dinotefuran. These are mainly used to control harmful insects and pests to protect crops. Their main targets are nicotinic acetylcholine receptors. In the past two decades, the environmental residues of neonicotinoids have enormously increased due to large-scale applications. More and more neonicotinoids remain in the environment and pose severe toxicity to humans and animals. An increase in toxicological and hazardous pollution due to the introduction of neonicotinoids into the environment causes problems; thus, the systematic remediation of neonicotinoids is essential and in demand. Various technologies have been developed to remove insecticidal residues from soil and water environments. Compared with non-bioremediation methods, bioremediation is a cost-effective and eco-friendly approach for the treatment of pesticide-polluted environments. Certain neonicotinoid-degrading microorganisms, including Bacillus, Mycobacterium, Pseudoxanthomonas, Rhizobium, Rhodococcus, Actinomycetes, and Stenotrophomonas, have been isolated and characterized. These microbes can degrade neonicotinoids under laboratory and field conditions. The microbial degradation pathways of neonicotinoids and the fate of several metabolites have been investigated in the literature. In addition, the neonicotinoid-degrading enzymes and the correlated genes in organisms have been explored. However, few reviews have focused on the neonicotinoid-degrading microorganisms along with metabolic pathways and degradation mechanisms. Therefore, this review aimed to summarize the microbial degradation and biochemical mechanisms of neonicotinoids. The potentials of neonicotinoid-degrading microbes for the bioremediation of contaminated sites were also discussed.
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Affiliation(s)
- Shimei Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ziqiu Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Wenping Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Sandhya Mishra
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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112
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Vezzulli L, Baker-Austin C, Kirschner A, Pruzzo C, Martinez-Urtaza J. Global emergence of environmental non-O1/O139 Vibrio cholerae infections linked with climate change: a neglected research field? Environ Microbiol 2020; 22:4342-4355. [PMID: 32337781 DOI: 10.1111/1462-2920.15040] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
The bacterium Vibrio cholerae is a natural inhabitant of aquatic ecosystems across the planet. V. cholerae serogroups O1 and O139 are responsible for cholera outbreaks in developing countries accounting for 3-5 million infections worldwide and 28.800-130.000 deaths per year according to the World Health Organization. In contrast, V. cholerae serogroups other than O1 and O139, also designated as V. cholerae non-O1/O139 (NOVC), are not associated with epidemic cholera but can cause other illnesses that may range in severity from mild (e.g. gastroenteritis, otitis, etc.) to life-threatening (e.g. necrotizing fasciitis). Although generally neglected, NOVC-related infections are on the rise and represent one of the most striking examples of emerging human diseases linked to climate change. NOVC strains are also believed to potentially contribute to the emergence of new pathogenic strains including strains with epidemic potential as a direct consequence of genetic exchange mechanisms such as horizontal gene transfer and genetic recombination. Besides general features concerning the biology and ecology of NOVC strains and their associated diseases, this review aims to highlight the most relevant aspects related to the emergence and potential threat posed by NOVC strains under a rapidly changing environmental and climatic scenario.
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Affiliation(s)
- Luigi Vezzulli
- Department of Earth, Environmental and Life Sciences (DISTAV), University of Genoa, Genoa, Italy
| | - Craig Baker-Austin
- Centre for Environment, Fisheries and Aquaculture Science, CEFAS, Weymouth, UK
| | - Alexander Kirschner
- Institute for Hygiene and Applied Immunology - Water Microbiology, Medical University of Vienna, Vienna, Austria.,Division Water Quality and Health, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Carla Pruzzo
- Department of Earth, Environmental and Life Sciences (DISTAV), University of Genoa, Genoa, Italy
| | - Jaime Martinez-Urtaza
- Centre for Environment, Fisheries and Aquaculture Science, CEFAS, Weymouth, UK.,Department of Genetics and Microbiology, Facultat de Biociéncies, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain
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113
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Chlorous acid is a more potent antibacterial agent than sodium hypochlorite against Campylobacter. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.107046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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114
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Foddai ACG, Grant IR. Methods for detection of viable foodborne pathogens: current state-of-art and future prospects. Appl Microbiol Biotechnol 2020; 104:4281-4288. [PMID: 32215710 PMCID: PMC7190587 DOI: 10.1007/s00253-020-10542-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/06/2020] [Accepted: 03/11/2020] [Indexed: 12/21/2022]
Abstract
The ability to rapidly detect viable pathogens in food is important for public health and food safety reasons. Culture-based detection methods, the traditional means of demonstrating microbial viability, tend to be laborious, time consuming and slow to provide results. Several culture-independent methods to detect viable pathogens have been reported in recent years, including both nucleic acid-based (PCR combined with use of cell viability dyes or reverse-transcriptase PCR to detect messenger RNA) and phage-based (plaque assay or phage amplification and lysis plus PCR/qPCR, immunoassay or enzymatic assay to detect host DNA, progeny phages or intracellular components) methods. Some of these newer methods, particularly phage-based methods, show promise in terms of speed, sensitivity of detection and cost compared with culture for food testing. This review provides an overview of these new approaches and their food testing applications, and discusses their current limitations and future prospects in relation to detection of viable pathogens in food. KEY POINTS: • Cultural methods may be 'gold standard' for assessing viability of pathogens, but they are too slow. • Nucleic acid-based methods offer speed of detection but not consistently proof of cell viability. • Phage-based methods appear to offer best alternative to culture for detecting viable pathogens.
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Affiliation(s)
- Antonio C G Foddai
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK
| | - Irene R Grant
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland, UK.
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115
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Salive AFV, Prudêncio CV, Baglinière F, Oliveira LL, Ferreira SO, Vanetti MCD. Comparison of stress conditions to induce viable but non-cultivable state in Salmonella. Braz J Microbiol 2020; 51:1269-1277. [PMID: 32291740 DOI: 10.1007/s42770-020-00261-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 03/10/2020] [Indexed: 12/18/2022] Open
Abstract
Salmonella can enter on the viable but non-culturable state (VBNC), characterized by the loss of ability to grow in routine culture media hindering detection by conventional methods and underestimation of the pathogen. Despite advances in research done so far, studies comparing conditions that lead Salmonella into the VBNC state are scarce. The main objective of this study was to evaluate different stresses to induce Salmonella to the VNBC state. Osmotic (1.2 M NaCl), acid (peracetic acid, 5.66 mg/mL) and oxidative (hydrogen peroxide, 1.20 mg/mL) stress were used at 4 °C to induce Salmonella enterica serovars Enteritidis and Typhimurium to the VBNC state. The culturability loss was monitored in the brain heart infusion (BHI) broth and agar, and the viability was determined by fluorescence microscopy, using the Live/Dead® kit, and by flow cytometry. Besides, the morphological characterization by atomic force microscopy (AFM) was performed. Storage in 1.2 M NaCl at 4 °C induced the VBNC state in Salmonella cells for periods longer than 121 days, and the percentage of viable cells has reached above 80.9%. More aggressive stress conditions promoted by peracetic acid and hydrogen peroxide induced the VBNC state in periods of, at most 0.14 day, and resulted in percentages of 8.5% to 45.5% viable cells, respectively. The counts of viable cells in the flow cytometer corroborate the results obtained by microscopic counts. The VBNC cells obtained in 1.2 M NaCl at 4 °C showed morphological changes, reducing the size and changing the morphology from bacillary to coccoid. No morphological change was observed on the cells stressed by acid or oxidant compounds.
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Affiliation(s)
| | - Cláudia Vieira Prudêncio
- Center of Biological and Health Sciences, Federal University of Western of Bahia, Barreiras, Bahia, Brazil
| | - François Baglinière
- Department of Microbiology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
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116
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Increased Staphylococcus aureus Biofilm Formation on Biodegradable Poly(3-Hydroxybutyrate)-Implants Compared with Conventional Orthopedic Implants: An In Vitro Analysis. J Orthop Trauma 2020; 34:210-215. [PMID: 32195889 DOI: 10.1097/bot.0000000000001674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare the biofilm formation on a biodegradable material, poly(3-hydroxybutyrate) (PHB), with that on conventional titanium (Ti) and steel (St) implant material. METHODS Pins made of the different materials were incubated in Müller-Hinton broth inoculated with 2 × 10 colony-forming units (CFU)·mL of Staphylococcus aureus for 2 and 7 days and then sonicated for the disruption of the biofilms. CFU were counted to quantify the number of bacteria in the biofilm, and the cell proliferation assay 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H- tetrazolium-5-carboxanilid salt was used to evaluate their metabolic activity. Scanning electron microscopy visualized the structure of the biofilm. RESULTS We found a significantly higher metabolic activity and CFU count in the biofilm of PHB pins compared with St and Ti pins (analysis of variance, P < 0.0001). Scanning electron microscopy revealed structured biofilms on PHB pins already after 2 days of incubation, which was not observed on the other tested implants. CONCLUSION PHB implants seem to provide an environment that advantages the formation of biofilms of S. aureus, a common pathogen in implant-related infections. The amount of biofilm is higher on PHB implant compared with conventionally used orthopedic titanium and steel implants. To overcome the potential risk of surgical site infections linked to the clinical use of PHB implants, possible modifications of the material, increasing its antibacterial properties, need to be further investigated.
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117
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Kumar S, Gopinathan R, Chandra GK, Umapathy S, Saini DK. Rapid detection of bacterial infection and viability assessment with high specificity and sensitivity using Raman microspectroscopy. Anal Bioanal Chem 2020; 412:2505-2516. [PMID: 32072214 DOI: 10.1007/s00216-020-02474-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/05/2020] [Accepted: 01/30/2020] [Indexed: 01/15/2023]
Abstract
Infectious diseases caused by bacteria still pose major diagnostic challenges in spite of the availability of various molecular approaches. Irrespective of the type of infection, rapid identification of the causative pathogen with a high degree of sensitivity and specificity is essential for initiating appropriate treatment. While existing methods like PCR possess high sensitivity, they are incapable of identifying the viability status of the pathogen and those which can, like culturing, are inherently slow. To overcome these limitations, we developed a diagnostic platform based on Raman microspectroscopy, capable of detecting biochemical signatures from a single bacterium for identification as well as viability assessment. The study also establishes a decontamination protocol for handling live pathogenic bacteria which does not affect identification and viability testing, showing applicability in the analysis of sputum samples containing pathogenic mycobacterial strains. The minimal sample processing along with multivariate analysis of spectroscopic signatures provides an interface for automatic classification, allowing the prediction of unknown samples by mapping signatures onto available datasets. Also, the novelty of the current work is the demonstration of simultaneous identification and viability assessment at a single bacterial level for pathogenic bacteria. Graphical abstract.
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Affiliation(s)
- Srividya Kumar
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Renu Gopinathan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India
| | - Goutam Kumar Chandra
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India.,Department of Physics, NIT Calicut, Calicut, Kerala, 673601, India
| | - Siva Umapathy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India. .,Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, 560012, India.
| | - Deepak Kumar Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India. .,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, 560012, India. .,Centre for Infectious Diseases Research, Indian Institute of Science, Bangalore, 560012, India.
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118
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Wasfi R, Abdellatif GR, Elshishtawy HM, Ashour HM. First-time characterization of viable but non-culturable Proteus mirabilis: Induction and resuscitation. J Cell Mol Med 2020; 24:2791-2801. [PMID: 32030883 PMCID: PMC7077546 DOI: 10.1111/jcmm.15031] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/12/2019] [Accepted: 12/22/2019] [Indexed: 12/11/2022] Open
Abstract
Pathogenic bacteria can enter into a viable but non‐culturable (VBNC) state under unfavourable conditions. Proteus mirabilis is responsible for dire clinical consequences including septicaemia, urinary tract infections and pneumonia, but is not a species previously known to enter VBNC state. We suggested that stress‐induced P. mirabilis can enter a VBNC state in which it retains virulence. P. mirabilis isolates were incubated in extreme osmotic pressure, starvation, low temperature and low pH to induce a VBNC state. Resuscitation was induced by temperature upshift and inoculation in tryptone soy broth with Tween 20 and brain heart infusion broth. Cellular ultrastructure and gene expression were examined using transmission electron microscopy (TEM) and quantitative real‐time polymerase chain reaction (qPCR), respectively. High osmotic pressure and low acidity caused rapid entry into VBNC state. Temperature upshift caused the highest percentage of resuscitation (93%) under different induction conditions. In the VBNC state, cells showed aberrant and dwarf morphology, virulence genes and stress response genes (envZ and rpoS) were expressed (levels varied depending on strain and inducing factors). This is the first‐time characterization of VBNC P. mirabilis. The ability of P. mirabilis pathogenic strains to enter a stress‐induced VBNC state can be a serious public health threat.
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Affiliation(s)
- Reham Wasfi
- Department of Microbiology and Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), Giza, Egypt
| | - Ghada Refaat Abdellatif
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University (ACU), Giza, Egypt
| | - Hisham Mohamed Elshishtawy
- Microbial Genetics Laboratory, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt
| | - Hossam M Ashour
- Department of Biological Sciences, College of Arts and Sciences, University of South Florida St. Petersburg, St. Petersburg, Florida.,Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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119
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Taneja N, Mishra A, Batra N, Gupta P, Mahindroo J, Mohan B. Inland cholera in freshwater environs of north India. Vaccine 2020; 38 Suppl 1:A63-A72. [DOI: 10.1016/j.vaccine.2019.06.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 05/15/2019] [Accepted: 06/17/2019] [Indexed: 01/02/2023]
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120
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Zhang J, Song Z, Liu Q, Song Y. Recent advances in dielectrophoresis‐based cell viability assessment. Electrophoresis 2020; 41:917-932. [DOI: 10.1002/elps.201900340] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/28/2019] [Accepted: 11/29/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Junyan Zhang
- Department of Marine EngineeringDalian Maritime University Dalian P. R. China
| | - Zhenyu Song
- Department of RadiotherapyJiaozhou Central Hospital Qingdao P. R. China
| | - Qinxin Liu
- Department of Marine EngineeringDalian Maritime University Dalian P. R. China
| | - Yongxin Song
- Department of Marine EngineeringDalian Maritime University Dalian P. R. China
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Pan H, Dong K, Rao L, Zhao L, Wang Y, Liao X. The Association of Cell Division Regulated by DicC With the Formation of Viable but Non-culturable Escherichia coli O157:H7. Front Microbiol 2020; 10:2850. [PMID: 31921032 PMCID: PMC6915034 DOI: 10.3389/fmicb.2019.02850] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 11/25/2019] [Indexed: 12/23/2022] Open
Abstract
The viable but non-culturable (VBNC) state, in which bacteria fail to grow on routine culture media but are actually alive, has been widely recognized as a strategy adopted by bacteria to cope with stressful environments. However, little is known regarding the molecular mechanism of VBNC formation. Here, we aimed to elucidate the specific roles of cell division regulatory proteins and the cell growth rate during VBNC Escherichia coli O157:H7 formation. We have previously found that expression of dicC is reduced by 20.08-fold in VBNC E. coli O157:H7 compared to non-VBNC cells. Little is known about DicC except that it, along with DicA, appears to act as a regulator of cell division by regulating expression of the cell division inhibitor DicB. First, our results showed that the VBNC cell number increased in the ΔdicC mutant as well as the DicA-overexpressing strain but decreased in the DicC-overexpressing strain induced by high-pressure carbon dioxide, acid, and H2O2. Furthermore, the growth rates of both the DicA-overexpressing strain and the ΔdicC mutant were higher than that of the control strain, while DicC-overexpressing strain grew significantly more slowly than the vector strain. The level of the dicB gene, regulated by dicA and dicC and inhibiting cell division, was increased in the DicC-overexpressing strain and decreased in the ΔdicC mutant and DicA-overexpressing strain, which was consistent with the growth phenotypes. In addition, the dwarfing cell morphology of the ΔdicC mutant and DicA-overexpressing strain were observed by SEM and TEM. Taken together, our study demonstrates that DicC negatively regulates the formation of the VBNC state, and DicA enhances the ability of cells to enter the VBNC state. Besides, the cell growth rate and dwarfing cell morphology may be correlated with the formation of the VBNC state.
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Affiliation(s)
- Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Liang Zhao
- Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Yongtao Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture and Rural Affairs, Beijing, China
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122
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Lv R, Wang K, Feng J, Heeney DD, Liu D, Lu X. Detection and Quantification of Viable but Non-culturable Campylobacter jejuni. Front Microbiol 2020; 10:2920. [PMID: 31998253 PMCID: PMC6965164 DOI: 10.3389/fmicb.2019.02920] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/04/2019] [Indexed: 12/14/2022] Open
Abstract
Campylobacter can enter a viable but non-culturable (VBNC) state to evade various stresses, and this state is undetectable using traditional microbiological culturing techniques. These VBNC bacterial cells retain metabolism and demonstrate pathogenic potential due to their ability to resuscitate under favorable conditions. Rapid and accurate determination of VBNC Campylobacter is critical to further understand the induction and resuscitation of the dormancy state of this microbe in the agri-food system. Here, we integrated propidium monoazide (PMA) with real-time polymerase chain reaction (qPCR) targeting the rpoB gene to detect and quantify Campylobacter jejuni in the VBNC state. First, we optimized the concentration of PMA (20 μM) that could significantly inhibit the amplification of dead cells by qPCR with no significant interference on the amplification of viable cell DNA. PMA-qPCR was highly specific to C. jejuni with a limit of detection (LOD) of 2.43 log CFU/ml in pure bacterial culture. A standard curve for C. jejuni cell concentrations was established with the correlation coefficient of 0.9999 at the linear range of 3.43 to 8.43 log CFU/ml. Induction of C. jejuni into the VBNC state by osmotic stress (i.e., 7% NaCl) was rapid (<48 h) and effective (>10% population). The LOD of PMA-qPCR for VBNC C. jejuni exogenously applied to chicken breasts was 3.12 log CFU/g. In conclusion, PMA-qPCR is a rapid, specific, and sensitive method for the detection and quantification of VBNC C. jejuni in poultry products. This technique can give insight into the prevalence of VBNC Campylobacter in the environment and agri-food production system.
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Affiliation(s)
- Ruiling Lv
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada.,College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Kaidi Wang
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Jinsong Feng
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Dustin D Heeney
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Donghong Liu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Xiaonan Lu
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
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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] [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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124
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Li Y, Huang TY, Ye C, Chen L, Liang Y, Wang K, Liu J. Formation and Control of the Viable but Non-culturable State of Foodborne Pathogen Escherichia coli O157:H7. Front Microbiol 2020; 11:1202. [PMID: 32612584 PMCID: PMC7308729 DOI: 10.3389/fmicb.2020.01202] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/12/2020] [Indexed: 02/05/2023] Open
Abstract
As a common foodborne pathogen, Escherichia coli O157:H7 produces toxins causing serious diseases. However, traditional methods failed in detecting E. coli O157:H7 cells in the viable but non-culturable (VBNC) state, which poses a threat to food safety. This study aimed at investigating the formation, control, and detection of the VBNC state of E. coli O157:H7. Three factors including medium, salt, and acid concentrations were selected as a single variation. Orthogonal experiments were designed with three factors and four levels, and 16 experimental schemes were used. The formation of the VBNC state was examined by agar plate counting and LIVE/DEAD® BacLightTM bacterial viability kit with fluorescence microscopy. According to the effects of environmental conditions on the formation of the VBNC state of E. coli O157:H7, the inhibition on VBNC state formation was investigated. In addition, E. coli in the VBNC state in food samples (crystal cake) was detected by propidium monoazide-polymerase chain reaction (PMA-PCR) assays. Acetic acid concentration showed the most impact on VBNC formation of E. coli O157:H7, followed by medium and salt concentration. The addition of 1.0% acetic acid could directly kill E. coli O157:H7 and eliminate its VBNC formation. In crystal cake, 25, 50, or 100% medium with 1.0% acetic acid could inhibit VBNC state formation and kill E. coli O157:H7 within 3 days. The VBNC cell number was reduced by adding 1.0% acetic acid. PMA-PCR assay could be used to detect E. coli VBNC cells in crystal cake with detection limit at 104 CFU/ml. The understanding on the inducing and inhibitory conditions for the VBNC state of E. coli O157:H7 in a typical food system, as well as the development of an efficient VBNC cell detection method might aid in the control of VBNC E. coli O157:H7 cells in the food industry.
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Affiliation(s)
- Yanmei Li
- Department of Haematology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Teng-Yi Huang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Congxiu Ye
- Department of Dermato-Venereology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ling Chen
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Yi Liang
- Guangdong Zhongqing Font Biochemical Science and Technology Co. Ltd., Maoming, China
| | - Kan Wang
- Research Center for Translational Medicine, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
- *Correspondence: Junyan Liu,
| | - Junyan Liu
- Department of Civil and Environmental Engineering, A. James Clark School of Engineering, University of Maryland, College Park, MD, United States
- Kan Wang,
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Li Y, Huang TY, Mao Y, Chen Y, Shi F, Peng R, Chen J, Bai C, Chen L, Wang K, Liu J. Effect of Environmental Conditions on the Formation of the Viable but Nonculturable State of Pediococcus acidilactici BM-PA17927 and Its Control and Detection in Food System. Front Microbiol 2020; 11:586777. [PMID: 33117324 PMCID: PMC7550757 DOI: 10.3389/fmicb.2020.586777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 08/25/2020] [Indexed: 02/05/2023] Open
Abstract
Objective: This study aimed to investigate the effect of environmental conditions including nutrient content, acetic acid concentration, salt concentration, and temperature on the formation of viable but nonculturable (VBNC) state of Pediococcus acidilactici, as well as its control and detection in food system. Methods: Representing various environmental conditions in different food systems, 16 induction groups were designed for the formation of VBNC state of P. acidilactici. Traditional plate counting was applied to measure the culturable cell numbers, and Live/Dead Bacterial Viability Kit combined with fluorescent microscopy was used to identify viable cells numbers. The inhibition of bacterial growth and VBNC state formation by adjusting the environmental conditions were investigated, and the clearance effect of VBNC cells in crystal cake system was studied. In addition, a propidium monoazide-polymerase chain reaction (PMA-PCR) assay was applied to detect the VBNC P. acidilactici cells in crystal cake food system. Results: Among the environmental conditions included in this study, acetic acid concentration had the greatest effect on the formation of VBNC state of P. acidilactici, followed by nutritional conditions and salt concentration. Reducing nutrients in the environment and treating with 1.0% acetic acid can inhibit P. acidilactici from entering the VBNC state. In the crystal cake system, the growth of P. acidilactici and the formation of VBNC state can be inhibited by adding 1.0% acetic acid and storing at -20°C. In crystal cake system, the PMA-PCR assay can be used to detect VBNC P. acidilactici cells at a concentration higher than 104 cells/ml. Conclusion: The VBNC state of P. acidilactici can be influenced by the changing of environmental conditions, and PMA-PCR assay can be applied in food system for the detection of VBNC P. acidilactici cells.
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Affiliation(s)
- Yanmei Li
- Department of Haematology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Teng-Yi Huang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Yuzhu Mao
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Yanni Chen
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Fan Shi
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Ruixin Peng
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Jinxuan Chen
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
| | - Caiying Bai
- Guangdong Women and Children Hospital, Guangzhou, China
| | - Ling Chen
- School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, China
- Research Institute for Food Nutrition and Human Health, Guangzhou, China
| | - Kan Wang
- Research Center for Translational Medicine, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
- Kan Wang,
| | - Junyan Liu
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, United States
- *Correspondence: Junyan Liu,
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Ben Maamar S, Hu J, Hartmann EM. Implications of indoor microbial ecology and evolution on antibiotic resistance. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2020; 30:1-15. [PMID: 31591493 PMCID: PMC8075925 DOI: 10.1038/s41370-019-0171-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/17/2019] [Accepted: 08/18/2019] [Indexed: 05/19/2023]
Abstract
The indoor environment is an important source of microbial exposures for its human occupants. While we naturally want to favor positive health outcomes, built environment design and operation may counter-intuitively favor negative health outcomes, particularly with regard to antibiotic resistance. Indoor environments contain microbes from both human and non-human origins, providing a unique venue for microbial interactions, including horizontal gene transfer. Furthermore, stressors present in the built environment could favor the exchange of genetic material in general and the retention of antibiotic resistance genes in particular. Intrinsic and acquired antibiotic resistance both pose a potential threat to human health; these phenomena need to be considered and controlled separately. The presence of both environmental and human-associated microbes, along with their associated antibiotic resistance genes, in the face of stressors, including antimicrobial chemicals, creates a unique opportunity for the undesirable spread of antibiotic resistance. In this review, we summarize studies and findings related to various interactions between human-associated bacteria, environmental bacteria, and built environment conditions, and particularly their relation to antibiotic resistance, aiming to guide "healthy" building design.
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Affiliation(s)
- Sarah Ben Maamar
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Jinglin Hu
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
| | - Erica M Hartmann
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA.
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Hadjilouka A, Gkolfakis P, Patlaka A, Grounta A, Vourli G, Paramithiotis S, Touloumi G, Triantafyllou K, Drosinos EH. In Vitro Gene Transcription of Listeria monocytogenes after Exposure to Human Gastric and Duodenal Aspirates. J Food Prot 2020; 83:89-100. [PMID: 31855615 DOI: 10.4315/0362-028x.jfp-19-210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of the present study was to assess, for the first time to our knowledge, Listeria monocytogenes CFU changes, as well as to determine the transcription of key virulence genes, namely, sigB, prfA, hly, plcA, plcB, inlA, inlB, inlC, inlJ, inlP, and lmo2672 after in vitro exposure to human gastric and duodenal aspirates. Furthermore, investigations of the potential correlation between CFU changes and gene regulation with factors influencing gastric (proton pump inhibitor intake and presence of gastric atrophy) and duodenal pH were the secondary study aims. Gastric and duodenal fluids that were collected from 25 individuals undergoing upper gastrointestinal endoscopy were inoculated with L. monocytogenes serotype 4b strain LQC 15257 at 9 log CFU·mL-1 and incubated at 37°C for 100 min and 2 h, respectively, with the time corresponding to the actual exposure time to gastric and duodenal fluids in the human gastrointestinal tract. Sampling was performed upon gastric fluid inoculation, after incubation of the inoculated gastric fluids, upon pathogen resuspension in duodenal fluids and after incubation of the inoculated duodenal fluids. L. monocytogenes CFU changes were assessed by colony counting, as well as reverse transcription quantitative PCR by using inlB as a target. Gene transcription was assessed by reverse transcription quantitative PCR. In 56% of the cases, reduction of the pathogen CFU occurred immediately after exposure to gastric aspirate. Upregulation of hly and inlC was observed in 52 and 58% of the cases, respectively. On the contrary, no upregulation or downregulation was noticed regarding sigB, prfA, plcA, plcB, inlA, inlB, inlJ, inlP, and lmo2672. In addition, sigB and plcA transcription was positively and negatively associated, respectively, with an increase of the pH value, and inlA transcription was negatively associated with the presence of gastric atrophy. Finally, a positive correlation between the transcriptomic responses of plcB, inlA, inlB, inlC, inlJ, inlP, and lmo2672 was detected. This study revealed that the CFU of the pathogen was negatively affected after exposure to human gastroduodenal aspirates, as well as significant correlations between the characteristics of the aspirates with the virulence potential of the pathogen.
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Affiliation(s)
- Agni Hadjilouka
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens 118 55, Greece (ORCID: https://orcid.org/0000-0002-6062-1701 [E.H.D.])
| | - Paraskevas Gkolfakis
- Hepatogastroenterology Unit, Second Department of Internal Medicine-Propaedeutic, Research Institute and Diabetes Center "Attikon" University General Hospital, Haidari 124 62, Greece
| | - Apostolia Patlaka
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens 118 55, Greece (ORCID: https://orcid.org/0000-0002-6062-1701 [E.H.D.])
| | - Athena Grounta
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens 118 55, Greece (ORCID: https://orcid.org/0000-0002-6062-1701 [E.H.D.])
| | - Georgia Vourli
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, Athens 115 27, Greece
| | - Spiros Paramithiotis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens 118 55, Greece (ORCID: https://orcid.org/0000-0002-6062-1701 [E.H.D.])
| | - Giota Touloumi
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, Athens 115 27, Greece
| | - Konstantinos Triantafyllou
- Hepatogastroenterology Unit, Second Department of Internal Medicine-Propaedeutic, Research Institute and Diabetes Center "Attikon" University General Hospital, Haidari 124 62, Greece
| | - Eleftherios H Drosinos
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens 118 55, Greece (ORCID: https://orcid.org/0000-0002-6062-1701 [E.H.D.])
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128
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Ogunniyi AD, Dandie CE, Ferro S, Hall B, Drigo B, Brunetti G, Venter H, Myers B, Deo P, Donner E, Lombi E. Comparative antibacterial activities of neutral electrolyzed oxidizing water and other chlorine-based sanitizers. Sci Rep 2019; 9:19955. [PMID: 31882630 PMCID: PMC6934530 DOI: 10.1038/s41598-019-56248-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/29/2019] [Indexed: 12/16/2022] Open
Abstract
There is increasing demand for safe and effective sanitizers for irrigation water disinfection to prevent transmission of foodborne pathogens to fresh produce. Here we compared the efficacy of pH-neutral electrolyzed oxidizing water (EOW), sodium hypochlorite (NaClO) and chlorine dioxide (ClO2) against single and mixed populations of E. coli, Listeria and Salmonella under a range of pH and organic matter content. EOW treatment of the mixed bacterial suspension resulted in a dose-dependent (<1 mg/L free chlorine), rapid (<2 min) and effective (4-6 Log10) reduction of the microbial load in water devoid of organic matter under the range of pH conditions tested (pH, 6.0, 7.0, 8.4 and 9.2). The efficacy of EOW containing 5 mg/L free chlorine was unaffected by increasing organic matter, and compared favourably with equivalent concentrations of NaClO and ClO2. EOW at 20 mg/L free chlorine was more effective than NaClO and ClO2 in reducing bacterial populations in the presence of high (20-100 mg/L) dissolved organic carbon, and no regrowth or metabolic activity was observed for EOW-treated bacteria at this concentration upon reculturing in rich media. Thus, EOW is as effective or more effective than other common chlorine-based sanitizers for pathogen reduction in contaminated water. EOW's other characteristics, such as neutral pH and ease of handling, indicate its suitability for fresh produce sanitation.
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Affiliation(s)
- Abiodun D Ogunniyi
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia.
| | - Catherine E Dandie
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Sergio Ferro
- Ecas4 Australia Pty Ltd, 8/1 London Road, Mile End South, South Australia, Australia
| | - Barbara Hall
- Plant Health and Biosecurity, SARDI, Adelaide, South Australia, Australia
| | - Barbara Drigo
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Gianluca Brunetti
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Henrietta Venter
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Baden Myers
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Permal Deo
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Erica Donner
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Enzo Lombi
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia, Australia
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129
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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130
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Gorski L, Rivadeneira P, Cooley MB. New strategies for the enumeration of enteric pathogens in water. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:765-776. [PMID: 31342654 DOI: 10.1111/1758-2229.12786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/15/2019] [Accepted: 07/21/2019] [Indexed: 06/10/2023]
Abstract
Water quality standards for drinking water and recreational waters have long been based on the enumeration of faecal coliforms in the various water supplies, with 0 CFU Escherichia coli/100 ml for drinking water and <126 CFU generic E. coli/100 ml for recreational waters. Irrigation water will soon undergo the same scrutiny in the United States. For over 50 years the most probable number method has been used by laboratories to estimate the level of viable bacteria in a sample, but this method is labour intensive and slow, especially if large numbers of samples need to be tested. In this review, we describe some recent innovations in methods to enumerate enteric pathogens in water. These methods are based on different reasoning schemes that can be categorized as biosensors and nucleic acid-based methods. All the methods described here used natural water sources. Several were also used to survey the bacterial levels in naturally contaminated samples. The different methods vary in their limits of detection, ease of use, and potential portability. Some combine very good limits of detection with the ability to overcome technical challenges; however, there is considerable room for improvement, as none of the methods are without shortcomings.
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Affiliation(s)
- Lisa Gorski
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA, USA
| | - Paula Rivadeneira
- Department of Soil, Water, and Environmental Science, The University of Arizona, Yuma, AZ, USA
| | - Michael B Cooley
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA, USA
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131
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Abdolahzadeh A, Dolgosheina EV, Unrau PJ. RNA detection with high specificity and sensitivity using nested fluorogenic Mango NASBA. RNA (NEW YORK, N.Y.) 2019; 25:1806-1813. [PMID: 31551299 PMCID: PMC6859864 DOI: 10.1261/rna.072629.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/16/2019] [Indexed: 05/30/2023]
Abstract
There is a pressing need for nucleic acid-based assays that are capable of rapidly and reliably detecting pathogenic organisms. Many of the techniques available for the detection of pathogenic RNA possess one or more limiting factors that make the detection of low-copy RNA challenging. Although RT-PCR is the most commonly used method for detecting pathogen-related RNA, it requires expensive thermocycling equipment and is comparatively slow. Isothermal methods promise procedural simplicity but have traditionally suffered from amplification artifacts that tend to preclude easy identification of target nucleic acids. Recently, the isothermal SHERLOCK system overcame this problem by using CRISPR to distinguish amplified target sequences from artifactual background signal. However, this system comes at the cost of introducing considerable enzymatic complexity and a corresponding increase in total assay time. Therefore, simpler and less expensive strategies are highly desirable. Here, we demonstrate that by nesting NASBA primers and modifying the NASBA inner primers to encode an RNA Mango aptamer sequence we can dramatically increase the sensitivity of NASBA to 1.5 RNA molecules per microliter. As this isothermal nucleic acid detection scheme directly produces a fluorescent reporter, real-time detection is intrinsic to the assay. Nested Mango NASBA is highly specific and, in contrast to existing RNA detection systems, offers a cheap, simple, and specific way to rapidly detect single-molecule amounts of pathogenic RNA.
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Affiliation(s)
- Amir Abdolahzadeh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Elena V Dolgosheina
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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132
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Fleiszig SMJ, Kroken AR, Nieto V, Grosser MR, Wan SJ, Metruccio MME, Evans DJ. Contact lens-related corneal infection: Intrinsic resistance and its compromise. Prog Retin Eye Res 2019; 76:100804. [PMID: 31756497 DOI: 10.1016/j.preteyeres.2019.100804] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022]
Abstract
Contact lenses represent a widely utilized form of vision correction with more than 140 million wearers worldwide. Although generally well-tolerated, contact lenses can cause corneal infection (microbial keratitis), with an approximate annualized incidence ranging from ~2 to ~20 cases per 10,000 wearers, and sometimes resulting in permanent vision loss. Research suggests that the pathogenesis of contact lens-associated microbial keratitis is complex and multifactorial, likely requiring multiple conspiring factors that compromise the intrinsic resistance of a healthy cornea to infection. Here, we outline our perspective of the mechanisms by which contact lens wear sometimes renders the cornea susceptible to infection, focusing primarily on our own research efforts during the past three decades. This has included studies of host factors underlying the constitutive barrier function of the healthy cornea, its response to bacterial challenge when intrinsic resistance is not compromised, pathogen virulence mechanisms, and the effects of contact lens wear that alter the outcome of host-microbe interactions. For almost all of this work, we have utilized the bacterium Pseudomonas aeruginosa because it is the leading cause of lens-related microbial keratitis. While not yet common among corneal isolates, clinical isolates of P. aeruginosa have emerged that are resistant to virtually all currently available antibiotics, leading the United States CDC (Centers for Disease Control) to add P. aeruginosa to its list of most serious threats. Compounding this concern, the development of advanced contact lenses for biosensing and augmented reality, together with the escalating incidence of myopia, could portent an epidemic of vision-threatening corneal infections in the future. Thankfully, technological advances in genomics, proteomics, metabolomics and imaging combined with emerging models of contact lens-associated P. aeruginosa infection hold promise for solving the problem - and possibly life-threatening infections impacting other tissues.
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Affiliation(s)
- Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Group in Vision Science, University of California, Berkeley, CA, USA; Graduate Groups in Microbiology and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
| | - Abby R Kroken
- School of Optometry, University of California, Berkeley, CA, USA
| | - Vincent Nieto
- School of Optometry, University of California, Berkeley, CA, USA
| | | | - Stephanie J Wan
- Graduate Group in Vision Science, University of California, Berkeley, CA, USA
| | | | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
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133
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Leygeber M, Lindemann D, Sachs CC, Kaganovitch E, Wiechert W, Nöh K, Kohlheyer D. Analyzing Microbial Population Heterogeneity—Expanding the Toolbox of Microfluidic Single-Cell Cultivations. J Mol Biol 2019; 431:4569-4588. [DOI: 10.1016/j.jmb.2019.04.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 01/15/2023]
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134
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Assessment of predatory bacteria and prey interactions using culture-based methods and EMA-qPCR. Microbiol Res 2019; 228:126305. [DOI: 10.1016/j.micres.2019.126305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/19/2019] [Accepted: 07/20/2019] [Indexed: 10/26/2022]
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135
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Zolfaghari M, Rezaei M, Mohabbati Mobarez A, Forozandeh Moghaddam M, Hosseini H, Khezri M. Virulence genes expression in viable but non-culturable state of Listeria monocytogenes in fish meat. FOOD SCI TECHNOL INT 2019; 26:205-212. [PMID: 31583896 DOI: 10.1177/1082013219877267] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This study aimed to evaluate the fate of Listeria monocytogenes in water microcosm and rainbow trout fillet under salinity stress of 0% and 30% NaCl at refrigerator temperature (4 ± 2 ℃). Bacterial culturability was studied by standard culture and colony count method. Reverse transcription-PCR (RT-PCR) of 16 S rRNA gene was used to detect viability of non-culturable bacteria. Also, the qualitative expression of pathogenic genes (hly and inlA) was studied using RT-PCR. The results showed that bacteria in water microcosm lost their culturability at 13 days under 0% salinity (starvation or distilled water) and at 27 days under 30% salinity; however, bacteria in rainbow trout fillet remained culturable under 0% and 30% NaCl. RT-PCR of 16 S rRNA gene was positive for all treatments during the period of this study, indicating the entering of L. monocytogenes into the viable but non-culturable state in water microcosm under 0% and 30% NaCl. Also, viable but non-culturable L. monocytogenes retained the expression of hly and inlA genes. So, it could be concluded that L. monocytogenes in viable but non-culturable state can cause serious health problems and further investigation is necessary to elucidate the effects of other processing and storage conditions (light, dark, smoking, etc.) on behavior of L. monocytogenes in smoked and salted fish.
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Affiliation(s)
- Mehdi Zolfaghari
- Fisheries Sciences Department, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
| | - Masoud Rezaei
- Seafood Processing Department, Faculty of Marine Sciences, Tarbiat Modares University, Noor, Iran
| | | | | | - Hedayat Hosseini
- Food Science and Technology Department, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Khezri
- Seafood Processing Department, Faculty of Marine Sciences, Tarbiat Modares University, Noor, Iran
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136
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RNA-based qPCR as a tool to quantify and to characterize dual-species biofilms. Sci Rep 2019; 9:13639. [PMID: 31541147 PMCID: PMC6754382 DOI: 10.1038/s41598-019-50094-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/06/2019] [Indexed: 12/22/2022] Open
Abstract
While considerable research has focused on studying individual-species, we now face the challenge of determining how interspecies interactions alter bacterial behaviours and pathogenesis. Pseudomonas aeruginosa and Staphylococcus aureus are often found to co-infect cystic-fibrosis patients. Curiously, their interaction is reported as competitive under laboratory conditions. Selecting appropriate methodologies is therefore critical to analyse multi-species communities. Herein, we demonstrated the major biases associated with qPCR quantification of bacterial populations and optimized a RNA-based qPCR able not only to quantify but also to characterize microbial interactions within dual-species biofilms composed by P. aeruginosa and S. aureus, as assessed by gene expression quantification. qPCR quantification was compared with flow-cytometry and culture-based quantification. Discrepancies between culture independent and culture dependent methods could be the result of the presence of viable but not-cultivable bacteria within the biofilm. Fluorescence microscopy confirmed this. A higher sensitivity to detect viable cells further highlights the potentialities of qPCR approach to quantify biofilm communities. By using bacterial RNA and an exogenous mRNA control, it was also possible to characterize bacterial transcriptomic profile, being this a major advantage of this method.
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137
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Handorf O, Schnabel U, Bösel A, Weihe T, Bekeschus S, Graf AC, Riedel K, Ehlbeck J. Antimicrobial effects of microwave-induced plasma torch (MiniMIP) treatment on Candida albicans biofilms. Microb Biotechnol 2019; 12:1034-1048. [PMID: 31264377 PMCID: PMC6680639 DOI: 10.1111/1751-7915.13459] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 06/05/2019] [Accepted: 06/17/2019] [Indexed: 11/28/2022] Open
Abstract
The susceptibility of Candida albicans biofilms to a non-thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods, the C. albicans strain SC5314 was treated with a microwave-induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a 40 s plasma treatment time were observed for C. albicans. After such a treatment, the biofilms revealed an altered morphology of their cells by atomic force microscopy (AFM). Additionally, fluorescence microscopy and confocal laser scanning microscopy (CLSM) analyses of plasma-treated biofilms showed that an inactivation of cells mainly appeared on the bottom side of the biofilms. Thus, the plasma inactivation of the overgrown surface reveals a new possibility to combat biofilms.
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Affiliation(s)
- Oliver Handorf
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
| | - Uta Schnabel
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
- School of Food Science and Environmental Health, College of Sciences and HealthTechnological UniversityDublinCathal Brugha StreetD01 HV58DublinIreland
| | - André Bösel
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
| | - Thomas Weihe
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
| | - Sander Bekeschus
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
| | - Alexander Christian Graf
- Institute of Microbial Physiology and Molecular BiologyUniversity of GreifswaldFelix‐Hausdorff‐Str. 817489GreifswaldGermany
| | - Katharina Riedel
- Institute of Microbial Physiology and Molecular BiologyUniversity of GreifswaldFelix‐Hausdorff‐Str. 817489GreifswaldGermany
| | - Jörg Ehlbeck
- Leibniz Institute for Plasma Science and Technology (INP)Felix‐Hausdorff‐Str. 217489GreifswaldGermany
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138
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Foster E, Carney P, Liew D, Ademi Z, O'Brien T, Kwan P. First seizure presentations in adults: beyond assessment and treatment. J Neurol Neurosurg Psychiatry 2019; 90:1039-1045. [PMID: 30948624 DOI: 10.1136/jnnp-2018-320215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 03/05/2019] [Accepted: 03/05/2019] [Indexed: 11/04/2022]
Abstract
Almost 10% of people will experience at least one seizure over a lifetime. Although common, first seizures are serious events and warrant careful assessment and management. First seizures may be provoked by acute or remote symptomatic factors including life-threatening metabolic derangements, drug toxicity or structural brain lesions. An unprovoked first seizure may herald the onset of epilepsy and may be accompanied by medical and psychiatric illnesses. Accidents, injuries and death associated with first seizures are likely under-reported. The cognitive and emotional impact of first seizures is often neglected. Evaluation of a patient presenting with a first seizure requires careful history-taking and early specialist assessment, however optimal management strategies have not been extensively investigated. Further, advances in technology and the role of eHealth interventions such as telemedicine may be of value in the care of patients who have experienced a first seizure. This article reviews the impact and implications of first seizures beyond the scope provided in current guidelines which tend to focus on assessment and management. It examines the effect of first seizures on the well-being of patients; assesses morbidity and premature mortality in first seizures and discusses current and future directions to optimise safety and health of people with first seizures, with a focus on adult patients. Recognition of these issues is essential to provide adequate care for people with first seizures.
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Affiliation(s)
- Emma Foster
- Neurology, Alfred Health, Melbourne, Victoria, Australia .,Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Patrick Carney
- Department of Medicine, Eastern Health, Melbourne, Victoria, Australia.,Neuroscience and Mental Health, Florey Institute, Parkville, Victoria, Australia
| | - Danny Liew
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Zanfina Ademi
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Terry O'Brien
- Neurology, Alfred Health, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Patrick Kwan
- Neurology, Alfred Health, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia
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139
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Guo L, Ye C, Cui L, Wan K, Chen S, Zhang S, Yu X. Population and single cell metabolic activity of UV-induced VBNC bacteria determined by CTC-FCM and D 2O-labeled Raman spectroscopy. ENVIRONMENT INTERNATIONAL 2019; 130:104883. [PMID: 31229870 DOI: 10.1016/j.envint.2019.05.077] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/19/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
The occurrence of viable but non-culturable (VBNC) bacteria will result in significant underestimation of viable bacterial counts in drinking water. Whereas, much is unknown in characterizing their viability. In this study, two environmental isolates (Aeromonas sp. and Pseudomonas sp.) and two model strains (E. coli and S. aureus) were induced into VBNC state by UV irradiation. Then, their metabolic activity was determined by 5-cyano-2,3-ditolyl tetrazolium chloride combination flow cytometry (CTC-FCM) and D2O-labeled Raman spectroscopy, respectively, at both population and single cell levels. The results showed that almost all strains could enter VBNC state irradiated by ≥ 5 mJ/cm2 UV. When determined by CTC-FCM, the population metabolic activity for each strain did not vary significantly (p > 0.05) unless the UV dose reached 200 mJ/cm2. Their single cell activity spectrum narrowed slightly, as indicated by changes in the standard deviation of the logarithmic normal distribution (σ) of 0.015-0.033. This minute difference suggested the CTC-FCM method was suitable for assessing the essential viability of VBNC bacteria. With respect to Raman method, an obvious dose-response effect was recorded. With the UV dosages increased from 10 to 200 mJ/cm2, the CD/(CD + CH) for the four strains were reduced to between 95.7% and 47.9% of unirradiated controls, depending on strain and UV dose. Meanwhile, the single cellular Raman spectrum showed much more heterogeneously metabolic activity distribution, with some cells even entering metabolic "silence". Considering the ubiquitous participation of water in biochemical processes, the Raman method was more appropriate in assessing the overall metabolic activity. The above findings can not only be a reference for VBNC mechanism studies, but also have the potential in optimizing disinfection and other bacterial removal processes.
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Affiliation(s)
- Lizheng Guo
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chengsong Ye
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Li Cui
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Kun Wan
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Sheng Chen
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shenghua Zhang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Xin Yu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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140
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Rogers CR, Okuyemi K, Paskett ED, Thorpe RJ, Rogers TN, Hung M, Zickmund S, Riley C, Fetters MD. Study protocol for developing #CuttingCRC: a barbershop-based trial on masculinity barriers to care and colorectal cancer screening uptake among African-American men using an exploratory sequential mixed-methods design. BMJ Open 2019; 9:e030000. [PMID: 31345981 PMCID: PMC6661686 DOI: 10.1136/bmjopen-2019-030000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/26/2019] [Accepted: 06/28/2019] [Indexed: 01/16/2023] Open
Abstract
INTRODUCTION Colorectal cancer (CRC) is preventable, as screening leads to the identification and removal of precancerous polyps. African-American men consistently have the highest CRC mortality rates, and their CRC-screening uptake remains low for complex reasons. Culture-specific masculinity barriers to care may contribute to the low uptake among African-American men. Examining these barriers to care is vital as CRC screening may challenge cultural role expectations of African-American men, whose tendency is to delay help-seeking medical care. Barbershops provide a pathway for reaching African-American men with masculinity barriers to care who are not regularly receiving healthcare services and CRC screening. This study aims to develop and pilot test a theory-driven, culture-specific, barbershop-based intervention targeting masculinity barriers to care and CRC-screening uptake among African-American men ages 45-75. METHODS AND ANALYSIS Guided by the theory of planned behaviour and the behaviour change wheel, we will use a multistage mixed-methods study design, beginning with an exploratory sequential approach to validate items for subsequent use in a pilot mixed-methods intervention. First, we will collect and analyse qualitative data from focus groups, cognitive interviews and expert item review to validate and test a culture-specific Masculinity Barriers to Care Scale (MBCS) among African-American men. Next, we will administer the MBCS to our target population as an online quantitative survey and evaluate the association between scores and CRC-screening uptake. Then, we will consider existing evidence-based approaches, our integrated results (qualitative +quantitative), and community input to design a culture-specific, behavioural intervention aimed at increasing CRC-screening uptake among African-American men and feasible for barbershop delivery. We will test the peer intervention in a pilot study with a two-arm cluster randomised design (six barbershops, randomised by site) to reduce contamination and account for barbershop culture differences. Our primary outcomes for the pilot are recruitment, sample size estimation, preliminary efficacy and acceptability. ETHICS AND DISSEMINATION Ethics approval was obtained from the University of Utah Institutional Review Board (00113679), who will also be responsible for receiving communication updates regarding important protocol modifications. To ensure confidentiality, data dispersed to project team members will be blinded of any identifying participant information. Study results will be disseminated through publications in peer-reviewed journals, community dialogue sessions, and presentations at conferences. TRIAL REGISTRATION NUMBER ClinicalTrials.gov identifier: NCT03733197 (Pre-results);https://clinicaltrials.gov/ct2/show/NCT03733197.
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Affiliation(s)
- Charles R Rogers
- Family & Preventive Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Kola Okuyemi
- Family & Preventive Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Electra D Paskett
- Internal Medicine, College of Medicine, Ohio State University, Columbus, Ohio, USA
| | - Roland J Thorpe
- Program for Research on Men's Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Tiana N Rogers
- Sorenson Impact Center, University of Utah Eccles School of Business, Salt Lake City, Utah, USA
| | - Man Hung
- College of Dental Medicine, Roseman University of Health Sciences, South Jordan, Utah, USA
| | - Susan Zickmund
- Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Colin Riley
- Family & Preventive Medicine, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Michael D Fetters
- Department of Family Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Alonso B, Pérez-Granda MJ, Latorre MC, Rodríguez C, Sánchez-Carrillo C, Muñoz P, Guembe M. Is heparinized 40% ethanol lock solution efficient for reducing bacterial and fungal biofilms in an in vitro model? PLoS One 2019; 14:e0219098. [PMID: 31283786 PMCID: PMC6613681 DOI: 10.1371/journal.pone.0219098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/16/2019] [Indexed: 12/04/2022] Open
Abstract
Background We applied an in vitro model to evaluate the efficacy of a heparinized 40% ethanol-based lock solution in a wide variety of clinical isolates causing C-RBSI. Methods A total of 100 clinical strains were collected retrospectively from the blood of patients with C-RBSI. The reduction in biomass and metabolic activity of biofilms was measured using the crystal violet (CV) assay and XTT assay, respectively. Regrowth inhibition (RI) was measured within 24 hours and 72 hours of ethanol lock therapy. Percentage reduction of ≥ 85% in RI was considered to be successful. Results Ethanol lock was more effective in reducing metabolic activity than in reducing biomass (83% vs. 50%, respectively). Percentages of RI diminished as regrowth was prolonged (57% for 24 hours and 17% for 72 hours of regrowth). No statistically significant intraspecies differences were found in biofilm reduction or in RI (p>0.05). Conclusions The use of heparinized 40% ethanol lock solution for 72 hours significantly reduced biomass and metabolic activity in clinical isolates from patients with C-RBSI. However, as biofilm has an important regrowth rate, 40% ethanol solution was not able to fully eradicate biofilm in vitro.
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Affiliation(s)
- Beatriz Alonso
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
- * E-mail: (MG); (BA)
| | - María Jesús Pérez-Granda
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Cardiac Surgery Postoperative Care Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain
- CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
| | - María Consuelo Latorre
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Carmen Rodríguez
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Pharmacy Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Carlos Sánchez-Carrillo
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Patricia Muñoz
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
- CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
- Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - María Guembe
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
- * E-mail: (MG); (BA)
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142
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van Tatenhove-Pel RJ, Zwering E, Solopova A, Kuipers OP, Bachmann H. Ampicillin-treated Lactococcus lactis MG1363 populations contain persisters as well as viable but non-culturable cells. Sci Rep 2019; 9:9867. [PMID: 31285492 PMCID: PMC6614399 DOI: 10.1038/s41598-019-46344-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/23/2019] [Indexed: 12/12/2022] Open
Abstract
Lactococcus lactis is used as cell-factory and strain selections are regularly performed to improve production processes. When selection regimes only allow desired phenotypes to survive, for instance by using antibiotics to select for cells that do not grow in a specific condition, the presence of more resistant subpopulations with a wildtype genotype severely slows down the procedure. While the food grade organism L. lactis is not often exposed to antibiotics we characterized its response to ampicillin in more detail, to better understand emerging population heterogeneity and how this might affect strain selection procedures. Using growth-dependent viability assays we identified persister subpopulations in stationary and exponential phase. Growth-independent viability assays revealed a 100 times larger subpopulation that did not grow on plates or in liquid medium, but had an intact membrane and could maintain a pH gradient. Over one third of these cells restored their intracellular pH when we induced a temporary collapse, indicating that this subpopulation was metabolically active and in a viable but non-culturable state. Exposure of L. lactis MG1363 to ampicillin therefore results in a heterogeneous population response with different dormancy states. These dormant cells should be considered in survival-based strain selection procedures.
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Affiliation(s)
- Rinke J van Tatenhove-Pel
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands
- NIZO Food Research, Kernhemseweg 2, 6718 ZB, Ede, The Netherlands
| | - Emile Zwering
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands
| | - Ana Solopova
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Herwig Bachmann
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081 HV, Amsterdam, The Netherlands.
- NIZO Food Research, Kernhemseweg 2, 6718 ZB, Ede, The Netherlands.
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143
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Yuan L, Hansen MF, Røder HL, Wang N, Burmølle M, He G. Mixed-species biofilms in the food industry: Current knowledge and novel control strategies. Crit Rev Food Sci Nutr 2019; 60:2277-2293. [PMID: 31257907 DOI: 10.1080/10408398.2019.1632790] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Attachment of microorganisms to food contact surfaces and the subsequent formation of biofilms may cause equipment damage, food spoilage and even diseases. Mixed-species biofilms are ubiquitous in the food industry and they generally exhibit higher resistance to disinfectants and antimicrobials compared to single-species biofilms. The physiology and metabolic activity of microorganisms in mixed-species biofilms are however rather complicated to study, and despite targeted research efforts, the potential role of mixed-species biofilms in food industry is still rather unexplored. In this review, we summarize recent studies in the context of bacterial social interactions in mixed-species biofilms, resistance to disinfectants, detection methods, and potential novel strategies to control the formation of mixed-species biofilms for enhanced food safety and food quality.
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Affiliation(s)
- Lei Yuan
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China.,Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Mads Frederik Hansen
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Lyng Røder
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ni Wang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Mette Burmølle
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Guoqing He
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
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144
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Frirdich E, Biboy J, Pryjma M, Lee J, Huynh S, Parker CT, Girardin SE, Vollmer W, Gaynor EC. The Campylobacter jejuni helical to coccoid transition involves changes to peptidoglycan and the ability to elicit an immune response. Mol Microbiol 2019; 112:280-301. [PMID: 31070821 PMCID: PMC6767375 DOI: 10.1111/mmi.14269] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2019] [Indexed: 12/20/2022]
Abstract
Campylobacter jejuni is a prevalent enteric pathogen that changes morphology from helical to coccoid under unfavorable conditions. Bacterial peptidoglycan maintains cell shape. As C. jejuni transformed from helical to coccoid, peptidoglycan dipeptides increased and tri- and tetrapeptides decreased. The DL-carboxypeptidase Pgp1 important for C. jejuni helical morphology and putative N-acetylmuramoyl-L-alanyl amidase AmiA were both involved in the coccoid transition. Mutants in pgp1 and amiA showed reduced coccoid formation, with ∆pgp1∆amiA producing minimal coccoids. Both ∆amiA and ∆amiA∆pgp1 lacked flagella and formed unseparated chains of cells consistent with a role for AmiA in cell separation. All strains accumulated peptidoglycan dipeptides over time, but only strains capable of becoming coccoid displayed tripeptide changes. C. jejuni helical shape and corresponding peptidoglycan structure are important for pathogenesis-related attributes. Concomitantly, changing to a coccoid morphology resulted in differences in pathogenic properties; coccoid C. jejuni were non-motile and non-infectious, with minimal adherence and invasion of epithelial cells and an inability to stimulate IL-8. Coccoid peptidoglycan exhibited reduced activation of innate immune receptors Nod1 and Nod2 versus helical peptidoglycan. C. jejuni also transitioned to coccoid within epithelial cells, so the inability of the immune system to detect coccoid C. jejuni may be significant in its pathogenesis.
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Affiliation(s)
- Emilisa Frirdich
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
| | - Jacob Biboy
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Mark Pryjma
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
| | - Jooeun Lee
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Steven Huynh
- Produce Safety and Microbiology Unit, Western Region Research CenterUSDAAgricultural Research ServiceAlbanyCAUSA
| | - Craig T. Parker
- Produce Safety and Microbiology Unit, Western Region Research CenterUSDAAgricultural Research ServiceAlbanyCAUSA
| | - Stephen E. Girardin
- Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONCanada
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular BiosciencesNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Erin C. Gaynor
- Department of Microbiology and ImmunologyUniversity of British ColumbiaVancouverBCCanada
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145
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Robben C, Witte AK, Schoder D, Stessl B, Rossmanith P, Mester P. A Fast and Easy ATP-Based Approach Enables MIC Testing for Non-resuscitating VBNC Pathogens. Front Microbiol 2019; 10:1365. [PMID: 31258524 PMCID: PMC6587809 DOI: 10.3389/fmicb.2019.01365] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 05/31/2019] [Indexed: 12/14/2022] Open
Abstract
Many bacteria enter the viable but non-culturable (VBNC) state to maximize resources and increase their tolerance to harmful conditions to cope with environmental stress, which has been described for a plethora of important human and foodborne pathogens. VBNC pathogens can potentially present a serious risk to human health as they are invisible to routine microbiological culture-based methods. Of high importance is the increased tolerance to antibiotics or disinfectant measures while in the VBNC state. The greatest remaining challenge for such investigations is the lack of an appropriate, cost-effective multi-species screening method due to experimental constraints. In this study, we investigated if de novo ATP production of cells in the VBNC state is a suitable indicator for overall cell viability that can be utilized to determine the minimum ATP inhibitory concentration (MAIC) of antibiotics and other antimicrobials. To validate this approach, heat-stress time-kill experiments were performed with both culturable and VBNC cells. We developed a comprehensive experimental setup and demonstrated the applicability of this VBNC–MIC assay for testing the tolerance of 12 strains of 4 important bacterial species (Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, and Listeria monocytogenes) in the VBNC state to eight important antimicrobials including four different antibiotics. We confirmed that bacteria in the VBNC state were resistant to all tested antibiotics (ampicillin, imipenem, ciprofloxacin, and gentamicin) and additionally insensitive to disinfectants (benzalkonium chloride and trioctylmethylammonium chloride) and preservatives (bronopol and sodium azide). These data emphasize the need for further research regarding the characteristics of bacterial pathogens in the VBNC state and present the advantages and high-throughput capabilities of ATP determinations to investigate tolerance of VBNC pathogens to antimicrobials. The presented method should be helpful in order to identify appropriate countermeasures, treatments, or disinfectants when confronted with bacterial pathogens in the VBNC state.
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Affiliation(s)
- Christian Robben
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department of Farm Animal and Public Health in Veterinary Medicine, Institute for Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Anna Kristina Witte
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department of Farm Animal and Public Health in Veterinary Medicine, Institute for Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Dagmar Schoder
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department of Farm Animal and Public Health in Veterinary Medicine, Institute for Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria.,Department of Farm Animal and Public Health in Veterinary Medicine, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Beatrix Stessl
- Department of Farm Animal and Public Health in Veterinary Medicine, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department of Farm Animal and Public Health in Veterinary Medicine, Institute for Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria.,Department of Farm Animal and Public Health in Veterinary Medicine, Institute of Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
| | - Patrick Mester
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department of Farm Animal and Public Health in Veterinary Medicine, Institute for Milk Hygiene, Milk Technology and Food Science, University of Veterinary Medicine, Vienna, Austria
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Polymeric Composites with Silver (I) Cyanoximates Inhibit Biofilm Formation of Gram-Positive and Gram-Negative Bacteria. Polymers (Basel) 2019; 11:polym11061018. [PMID: 31181853 PMCID: PMC6631325 DOI: 10.3390/polym11061018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/22/2019] [Accepted: 05/28/2019] [Indexed: 12/30/2022] Open
Abstract
Biofilms are surface-associated microbial communities known for their increased resistance to antimicrobials and host factors. This resistance introduces a critical clinical challenge, particularly in cases associated with implants increasing the predisposition for bacterial infections. Preventing such infections requires the development of novel antimicrobials or compounds that enhance bactericidal effect of currently available antibiotics. We have synthesized and characterized twelve novel silver(I) cyanoximates designated as Ag(ACO), Ag(BCO), Ag(CCO), Ag(ECO), Ag(PiCO), Ag(PICO) (yellow and red polymorphs), Ag(BIHCO), Ag(BIMCO), Ag(BOCO), Ag(BTCO), Ag(MCO) and Ag(PiPCO). The compounds exhibit a remarkable resistance to high intensity visible light, UV radiation and heat and have poor solubility in water. All these compounds can be well incorporated into the light-curable acrylate polymeric composites that are currently used as dental fillers or adhesives of indwelling medical devices. A range of dry weight % from 0.5 to 5.0 of the compounds was tested in this study. To study the potential of these compounds in preventing planktonic and biofilm growth of bacteria, we selected two human pathogens (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and Gram-positive environmental isolate Bacillus aryabhattai. Both planktonic and biofilm growth was abolished completely in the presence of 0.5% to 5% of the compounds. The most efficient inhibition was shown by Ag(PiCO), Ag(BIHCO) and Ag(BTCO). The inhibition of biofilm growth by Ag(PiCO)-yellow was confirmed by scanning electron microscopy (SEM). Application of Ag(BTCO) and Ag(PiCO)-red in combination with tobramycin, the antibiotic commonly used to treat P. aeruginosa infections, showed a significant synergistic effect. Finally, the inhibitory effect lasted for at least 120 h in P. aeruginosa and 36 h in S. aureus and B. aryabhattai. Overall, several silver(I) cyanoximates complexes efficiently prevent biofilm development of both Gram-negative and Gram-positive bacteria and present a particularly significant potential for applications against P. aeruginosa infections.
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147
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Kumar SS, Ghosh AR. Assessment of bacterial viability: a comprehensive review on recent advances and challenges. Microbiology (Reading) 2019; 165:593-610. [DOI: 10.1099/mic.0.000786] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Shravanthi S. Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
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148
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Wang P, Hu A, Fan X, Zhao X, Ge Y, Chen Y. Bacterial communities in prepared foods available at supermarkets in Beijing, China. Food Res Int 2019; 120:668-678. [DOI: 10.1016/j.foodres.2018.11.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/19/2018] [Accepted: 11/13/2018] [Indexed: 12/16/2022]
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149
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Golpayegani A, Douraghi M, Rezaei F, Alimohammadi M, Nodehi RN. Propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay for rapid detection of viable and viable but non-culturable (VBNC) Pseudomonas aeruginosa in swimming pools. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2019; 17:407-416. [PMID: 31297217 PMCID: PMC6582174 DOI: 10.1007/s40201-019-00359-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/21/2019] [Indexed: 05/17/2023]
Abstract
Lack of culturability in the viable but non-culturable (VBNC) bacteria and the ability to regain infectivity in favourable conditions is one of the new challenges of public health providers for Pseudomonas aeruginosa monitoring in environmental samples. Propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) is one of the promising methods for timely detection of VBNC pathogens in environmental samples. We developed and used a method for the first time to detection of VBNC P. aeruginosa in swimming pool water samples using a membrane filter (MF). Moreover, the dominant model of the distribution of colonies on the MF and the effect of the culture medium and MF type on colony recovery by MF were evaluated. Swimming pool samples were subjected to conventional culture-based, qPCR and PMA-qPCR methods and the results were compared for the presence of VBNC P. aeruginosa in the samples. The positivity rate was 21% and 75% for P. aeruginosa in water samples as confirmed by standard culture-based and qPCR methods, respectively. Furthermore, of 24 samples, 9 (37.5%) were positive for VBNC P. aeruginosa. The developed qPCR/PMA-qPCR assay can detect the VBNC bacteria directly from aquatic samples and may result in better monitoring of recreational waters.
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Affiliation(s)
- Abdolali Golpayegani
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Vice-Chancellor for Health, Bam University of Medical Sciences, Bam, Iran
- Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farhad Rezaei
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Alimohammadi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, PO Box 14155-6446, Tehran, Iran
| | - Ramin Nabizadeh Nodehi
- Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, PO Box 14155-6446, Tehran, Iran
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Brouwer AF, Eisenberg MC, Love NG, Eisenberg JNS. Phenotypic variations in persistence and infectivity between and within environmentally transmitted pathogen populations impact population-level epidemic dynamics. BMC Infect Dis 2019; 19:449. [PMID: 31113377 PMCID: PMC6530054 DOI: 10.1186/s12879-019-4054-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 04/30/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human pathogens transmitted through environmental pathways are subject to stress and pressures outside of the host. These pressures may cause pathogen pathovars to diverge in their environmental persistence and their infectivity on an evolutionary time-scale. On a shorter time-scale, a single-genotype pathogen population may display wide variation in persistence times and exhibit biphasic decay. METHODS We use a transmission modeling framework to develop an infectious disease model with biphasic pathogen decay. We take a differential algebra approach to assessing model identifiability, calculate basic reproduction numbers by the next generation method, and use simulation to explore model dynamics. RESULTS For both long and short time-scales, we demonstrate that epidemic-potential-preserving trade-offs have implications for epidemic dynamics: less infectious, more persistent pathogens cause epidemics to progress more slowly than more infectious, less persistent (labile) pathogens, even when the overall risk is the same. Using identifiability analysis, we show that the usual disease surveillance data does not sufficiently inform these underlying pathogen population dynamics, even when combined with basic environmental monitoring data. However, risk could be indirectly ascertained by developing methods to separately monitor labile and persistent subpopulations. Alternatively, determining the relative infectivity of persistent pathogen subpopulations and the rates of phenotypic conversion will help ascertain how much disease risk is associated with the long tails of biphasic decay. CONCLUSION A better understanding of persistence-infectivity trade-offs and associated dynamics can improve our ecological understanding of environmentally transmitted pathogens, as well as our risk assessment and disease control strategies.
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Affiliation(s)
- Andrew F Brouwer
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Abor, 48109, MI, USA.
| | - Marisa C Eisenberg
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Abor, 48109, MI, USA
| | - Nancy G Love
- Department of Civil and Environmental Engineering, University of Michigan, 1351 Beal Avenue, Ann Arbor, 48109, MI, USA
| | - Joseph N S Eisenberg
- Department of Epidemiology, University of Michigan, 1415 Washington Heights, Ann Abor, 48109, MI, USA
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