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Zhuang L, Gong J, Zhao Y, Yang J, Liu G, Zhao B, Song C, Zhang Y, Shen Q. Progress in methods for the detection of viable Escherichia coli. Analyst 2024; 149:1022-1049. [PMID: 38273740 DOI: 10.1039/d3an01750h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Escherichia coli (E. coli) is a prevalent enteric bacterium and a necessary organism to monitor for food safety and environmental purposes. Developing efficient and specific methods is critical for detecting and monitoring viable E. coli due to its high prevalence. Conventional culture methods are often laborious and time-consuming, and they offer limited capability in detecting potentially harmful viable but non-culturable E. coli in the tested sample, which highlights the need for improved approaches. Hence, there is a growing demand for accurate and sensitive methods to determine the presence of viable E. coli. This paper scrutinizes various methods for detecting viable E. coli, including culture-based methods, molecular methods that target DNAs and RNAs, bacteriophage-based methods, biosensors, and other emerging technologies. The review serves as a guide for researchers seeking additional methodological options and aiding in the development of rapid and precise assays. Moving forward, it is anticipated that methods for detecting E. coli will become more stable and robust, ultimately contributing significantly to the improvement of food safety and public health.
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Affiliation(s)
- Linlin Zhuang
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Jiansen Gong
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, P. R. China
| | - Ying Zhao
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Jianbo Yang
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Guofang Liu
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Bin Zhao
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Chunlei Song
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Yu Zhang
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Qiuping Shen
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
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2
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Panwar S, Duggirala KS, Yadav P, Debnath N, Yadav AK, Kumar A. Advanced diagnostic methods for identification of bacterial foodborne pathogens: contemporary and upcoming challenges. Crit Rev Biotechnol 2023; 43:982-1000. [PMID: 35994308 DOI: 10.1080/07388551.2022.2095253] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/09/2022] [Indexed: 11/03/2022]
Abstract
It is a public health imperative to have safe food and water across the population. Foodborne infections are one of the primary causes of sickness and mortality in both developed and developing countries. An estimated 100 million foodborne diseases and 120 000 foodborne illness-related fatalities occur each year in India. Several factors affect foodborne illness, such as improper farming methods, poor sanitary and hygienic conditions at all levels of the food supply chain, the lack of preventative measures in the food processing industry, the misuse of food additives, as well as improper storage and handling. In addition, chemical and microbiological combinations also play a key role in disease development. But recent disease outbreaks indicated that microbial pathogens played a major role in the development of foodborne diseases. Therefore, prompt, rapid, and accurate detection of high-risk food pathogens is extremely vital to warrant the safety of the food items. Conventional approaches for identifying foodborne pathogens are labor-intensive and cumbersome. As a result, a range of technologies for the rapid detection of foodborne bacterial pathogens have been developed. Presently, many methods are available for the instantaneous detection, identification, and monitoring of foodborne pathogens, such as nucleic acid-based methods, biosensor-based methods, and immunological-based methods. The goal of this review is to provide a complete evaluation of several existing and emerging strategies for detecting food-borne pathogens. Furthermore, this review outlines innovative methodologies and their uses in food testing, along with their existing limits and future possibilities in the detection of live pathogens in food.
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Affiliation(s)
- Surbhi Panwar
- Department of Genetics and Plant Breeding, Chaudhary Charan Singh University, Meerut, India
| | | | - Pooja Yadav
- Centre for Molecular Biology, Central University of Jammu, Jammu, India
| | - Nabendu Debnath
- Centre for Molecular Biology, Central University of Jammu, Jammu, India
| | - Ashok Kumar Yadav
- Centre for Molecular Biology, Central University of Jammu, Jammu, India
| | - Ashwani Kumar
- Department of Nutrition Biology, Central University of Haryana, Mahendergarh, India
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3
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Wang G, Nie X, Yang L, Liao H. A comparative analysis of quantitative detection methods for viable food-borne pathogens using RT-qPCR and PMA-qPCR. Lett Appl Microbiol 2023; 76:ovad120. [PMID: 37793793 DOI: 10.1093/lambio/ovad120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/25/2023] [Accepted: 10/03/2023] [Indexed: 10/06/2023]
Abstract
The accurate quantification of viable pathogens in food is crucial for ensuring food safety. This study mainly aimed to investigate the quantification of viable pathogens using PMA-qPCR and RT-qPCR, taking into account bacterial species, food matrices, and inactivation methods. The detection limit of PMA-qPCR for Salmonella serovars in simple matrices, such as culture broth, lake, or tap water, was found to be 102 cells per ml. Regarding the detection of Staphylococcus aureus and Escherichia coli in culture broth, as well as Salmonella in more complex matrices, such as juices and lab-made broth, both methods exhibited a detection limit of 103 cells per ml. Besides that, in adverse situations, there was a risk of overestimating the number of viable pathogens using PMA-qPCR. In addition, a conspicuous discrepancy between the results of PMA-qPCR/RT-qPCR and those of the plate counting assay was observed when Salmonella was exposed to isopropanol, H2O2, NaClO, sonication, or thermosonication. This suggests that it may survive in a viable but non-culturable state and poses a challenge for accurate quantification of viable cells using plate counting assay. Therefore, the results obtained by RT-qPCR were more objective compared to PMA-qPCR due to potential influences from bacteria species, surrounding media, and inactivation methods.
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Affiliation(s)
- Guoxiong Wang
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Xinyin Nie
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Lihong Yang
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Hongmei Liao
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
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4
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Ormsby MJ, Akinbobola A, Quilliam RS. Plastic pollution and fungal, protozoan, and helminth pathogens - A neglected environmental and public health issue? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 882:163093. [PMID: 36996975 DOI: 10.1016/j.scitotenv.2023.163093] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/10/2023] [Accepted: 03/23/2023] [Indexed: 06/01/2023]
Abstract
Plastic waste is ubiquitous in the environment and can become colonised by distinct microbial biofilm communities, known collectively as the 'plastisphere.' The plastisphere can facilitate the increased survival and dissemination of human pathogenic prokaryotes (e.g., bacteria); however, our understanding of the potential for plastics to harbour and disseminate eukaryotic pathogens is lacking. Eukaryotic microorganisms are abundant in natural environments and represent some of the most important disease-causing agents, collectively responsible for tens of millions of infections, and millions of deaths worldwide. While prokaryotic plastisphere communities in terrestrial, freshwater, and marine environments are relatively well characterised, such biofilms will also contain eukaryotic species. Here, we critically review the potential for fungal, protozoan, and helminth pathogens to associate with the plastisphere, and consider the regulation and mechanisms of this interaction. As the volume of plastics in the environment continues to rise there is an urgent need to understand the role of the plastisphere for the survival, virulence, dissemination, and transfer of eukaryotic pathogens, and the effect this can have on environmental and human health.
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Affiliation(s)
- Michael J Ormsby
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.
| | - Ayorinde Akinbobola
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Richard S Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
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Wijesinghe KM, Sabbih G, Algama CH, Syed R, Danquah MK, Dhakal S. FRET-Based Single-Molecule Detection of Pathogen Protein IsdA Using Computationally Selected Aptamers. Anal Chem 2023. [PMID: 37327207 DOI: 10.1021/acs.analchem.3c00717] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Iron-regulated surface determinant protein A (IsdA) is a key surface protein found in the foodborne bacteria─Staphylococcus aureus (S. aureus)─which is known to be critical for bacterial survival and colonization. S. aureus is pathogenic and has been linked to foodborne diseases; thus, early detection is critical to prevent diseases caused by this bacterium. Despite IsdA being a specific marker for S. aureus and several detection methods have been developed for sensitive detection of this bacteria such as cell culture, nucleic acids amplification, and other colorimetric and electrochemical methods, the detection of S. aureus through IsdA is underdeveloped. Here, by combining computational generation of target-guided aptamers and fluorescence resonance energy transfer (FRET)-based single-molecule analysis, we presented a widely applicable and robust detection method for IsdA. Three different RNA aptamers specific to the IsdA protein were identified and their ability to switch a FRET construct to a high-FRET state in the presence of protein was verified. The presented approach demonstrated the detection of IsdA down to picomolar levels (×10-12 M, equivalent to ∼1.1 femtomoles IsdA) with a dynamic range extending to ∼40 nM. The FRET-based single-molecule technique that we reported here is capable of detecting the foodborne pathogen protein IsdA with high sensitivity and specificity and has a broader application in the food industry and aptamer-based sensing field by enabling quantitative detection of a wide range of pathogen proteins.
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Affiliation(s)
- Kalani M Wijesinghe
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Godfred Sabbih
- Department of Chemical Engineering, University of Tennessee, Chattanooga, Tennessee 37403, United States
| | - Chamika Harshani Algama
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Rida Syed
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Michael K Danquah
- Department of Chemical Engineering, University of Tennessee, Chattanooga, Tennessee 37403, United States
| | - Soma Dhakal
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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6
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Ormsby MJ, White HL, Metcalf R, Oliver DM, Quilliam RS. Clinically important E. coli strains can persist, and retain their pathogenicity, on environmental plastic and fabric waste. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 326:121466. [PMID: 36958655 DOI: 10.1016/j.envpol.2023.121466] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/02/2023] [Accepted: 03/19/2023] [Indexed: 06/18/2023]
Abstract
Plastic waste is ubiquitous in the environment and there are increasing reports of such waste being colonised by human pathogens. However, the ability of pathogens to persist on plastics for long periods, and the risk that they pose to human health, is unknown. Here, under simulated environmental conditions, we aimed to determine if pathogenic bacteria can retain their virulence following a prolonged period on plastic. Using antibiotic selection and luciferase expression for quantification, we show that clinically important strains of E. coli can survive on plastic for at least 28-days. Importantly, these pathogens also retained their virulence (determined by using a Galleria mellonella model as a surrogate for human infection) and in some cases, had enhanced virulence following their recovery from the plastisphere. This indicates that plastics in the environment can act as reservoirs for human pathogens and could facilitate their persistence for extended periods of time. Most importantly human pathogens in the plastisphere are capable of retaining their pathogenicity. Pathogens colonising environmental plastic waste therefore pose a heightened public health risk, particularly in areas where people are exposed to pollution.
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Affiliation(s)
- Michael J Ormsby
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK.
| | - Hannah L White
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Rebecca Metcalf
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - David M Oliver
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Richard S Quilliam
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
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7
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Chan SH, Liau SH, Low YJ, Chng KR, Wu Y, Chan JSH, Tan LK. A Real-Time PCR Approach for Rapid Detection of Viable Salmonella Enteritidis in Shell Eggs. Microorganisms 2023; 11:microorganisms11040844. [PMID: 37110268 PMCID: PMC10143610 DOI: 10.3390/microorganisms11040844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
Rapid and robust detection assays for Salmonella Enteritidis (SE) in shell eggs are essential to enable a quick testing turnaround time (TAT) at the earliest checkpoint and to ensure effective food safety control. Real-time polymerase chain reaction (qPCR) assays provide a workaround for the protracted lead times associated with conventional Salmonella diagnostic testing. However, DNA-based analysis cannot reliably discriminate between signals from viable and dead bacteria. We developed a strategy based on an SE qPCR assay that can be integrated into system testing to accelerate the detection of viable SE in egg-enriched cultures and verify the yielded SE isolates. The specificity of the assay was evaluated against 89 Salmonella strains, and SE was accurately identified in every instance. To define the indicator for a viable bacteria readout, viable or heat-inactivated SE were spiked into shell egg contents to generate post-enriched, artificially contaminated cultures to establish the quantification cycle (Cq) for viable SE. Our study has demonstrated that this technique could potentially be applied to accurately identify viable SE during the screening stage of naturally contaminated shell eggs following enrichment to provide an early alert, and that it consistently identified the serotypes of SE isolates in a shorter time than conventional testing.
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Affiliation(s)
- Siew Herng Chan
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
| | - Sock Hwee Liau
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
| | - Ying Jia Low
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
| | - Kern Rei Chng
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
| | - Yuansheng Wu
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
| | - Joanne Sheot Harn Chan
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
- Department of Food Science and Technology, National University of Singapore, S14 Level 5 Science Drive 2, Singapore 117542, Singapore
| | - Li Kiang Tan
- National Centre for Food Science, Singapore Food Agency, 7 International Business Park, Singapore 609919, Singapore
- Correspondence: ; Tel.: +65-6019-5826
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Dawson P, Buyukyavuz A, Ionita C, Northcutt J. Effects of DNA extraction methods on the real time PCR quantification of Campylobacter jejuni, Campylobacter coli, and Campylobacter lari in chicken feces and ceca contents. Poult Sci 2022; 102:102369. [PMID: 36565641 PMCID: PMC9800320 DOI: 10.1016/j.psj.2022.102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/30/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022] Open
Abstract
Polymerase chain reaction (PCR) method was coupled with a DNA extraction to enumerate Campylobacter spp. from poultry gastrointestinal tract samples. Three experiments were conducted that included: 1) Development of a DNA standard curve related to bacterial DNA primers; 2) Design of a cell/genomic DNA extraction protocol to isolate Campylobacter spp. DNA from complex samples such as poultry feces; and 3) Comparison of PCR quantification to standard plate count methodology. The standard curve using primers for Campylobacter spp. was created for DNA extracted from environmental isolates with a linear range (R2 > 0.95) and with a high specificity for C. coli and C. jejuni recovered from poultry, swine and laboratory isolates. A 2-step extraction process of bacterial DNA from poultry feces was developed in which the cells were first concentrated using a gradient-centrifugation step followed by comparison of 4 DNA extraction methods. Two commercial DNA extraction methods (Zymo Research Quick DNA, and Invitrogen magnetic separation), a traditional phenol-chloroform DNA extraction method using proteinase K to inactivate DNAses, and an in-house isolation method for DNA extraction based on chaotropic salts were used. The middle gradient layer recovered 89% to 98% of the bacteria cells from the sample, with recovery dependent upon the Campylobacter genus. The 4 DNA extractions methods recovered 112 to 302 ug/nL of DNA. Finally, the qPCR and standard plate methods were highly correlated for enumerating Campylobacter spp. in the 2.0 to 8.0-log CFU range. Analyses of the results from this study demonstrate that the combination of the standard curve for Campylobacter spp. DNA primers, the gradient cell concentration method and DNA extraction techniques with qPCR can be used to enumerate Campylobacter spp. from poultry samples with findings similar those of traditional plate count methodology.
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Detection by real-time PCR and conventional culture of Salmonella Typhimurium and Listeria monocytogenes adhered to stainless steel surfaces under dry conditions. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.108971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Kreitlow A, Becker A, Schotte U, Malorny B, Plötz M, Abdulmawjood A. Establishment and validation of a loop-mediated isothermal amplification (LAMP) assay targeting the ttrRSBCA locus for rapid detection of Salmonella spp. in food. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Modernization of Control of Pathogenic Micro-Organisms in the Food-Chain Requires a Durable Role for Immunoaffinity-Based Detection Methodology-A Review. Foods 2021; 10:foods10040832. [PMID: 33920486 PMCID: PMC8069916 DOI: 10.3390/foods10040832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 01/03/2023] Open
Abstract
Food microbiology is deluged by a vastly growing plethora of analytical methods. This review endeavors to color the context into which methodology has to fit and underlines the importance of sampling and sample treatment. The context is that the highest risk of food contamination is through the animal and human fecal route with a majority of foodborne infections originating from sources in mass and domestic kitchens at the end of the food-chain. Containment requires easy-to-use, failsafe, single-use tests giving an overall risk score in situ. Conversely, progressive food-safety systems are relying increasingly on early assessment of batches and groups involving risk-based sampling, monitoring environment and herd/flock health status, and (historic) food-chain information. Accordingly, responsible field laboratories prefer specificity, multi-analyte, and high-throughput procedures. Under certain etiological and epidemiological circumstances, indirect antigen immunoaffinity assays outperform the diagnostic sensitivity and diagnostic specificity of e.g., nucleic acid sequence-based assays. The current bulk of testing involves therefore ante- and post-mortem probing of humoral response to several pathogens. In this review, the inclusion of immunoglobulins against additional invasive micro-organisms indicating the level of hygiene and ergo public health risks in tests is advocated. Immunomagnetic separation, immunochromatography, immunosensor, microsphere array, lab-on-a-chip/disc platforms increasingly in combination with nanotechnologies, are discussed. The heuristic development of portable and ambulant microfluidic devices is intriguing and promising. Tant pis, many new platforms seem unattainable as the industry standard. Comparability of results with those of reference methods hinders the implementation of new technologies. Whatever the scientific and technological excellence and incentives, the decision-maker determines this implementation after weighing mainly costs and business risks.
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Coelho JJ, Prieto ML, Hennessy A, Casey I, Woodcock T, Kennedy N. Determination of microbial numbers in anaerobically digested biofertilisers. ENVIRONMENTAL TECHNOLOGY 2021; 42:753-763. [PMID: 31314692 DOI: 10.1080/09593330.2019.1645214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
This study aimed to quantity total numbers of bacteria, fungi and archaea in different types of commercial liquid anaerobic digestates, and to identify common patterns in their microbial numbers post-digestion and possible implications of their use as biofertiliser. Relationships between microbial numbers and physical-chemical traits of the digestates were also investigated. Quantification was performed using culturable and molecular (quantitative PCR) approaches. Bacterial and fungal CFUs ranged up to five orders of magnitude (105-1010; 0-105 g-1 DW, respectively) between different types of anaerobic digestates. Bacterial, archaeal and fungal gene copy numbers (GCN) varied by two orders of magnitude (108-1010; 107-109; 104-106 g-1 DW, respectively) between digestates. All microbial variables analysed showed significant differences between the different types of anaerobic digestate investigated (p < 0.05). Culturable microbial numbers for fungi (6.43 × 104 CFU g-1 DW) were much lower than for bacteria (2.23 × 109 CFU g-1 DW). Gene copy numbers were highest for bacteria (16S) (1.09 × 1010 g-1 DW), followed by archaea (16S) (5.87 × 108 g-1 DW), and fungi (18S) (1.77 × 106 g-1 DW). Liquid anaerobic digestates were predominantly dominated by bacteria, followed by archaeal and fungal populations. At 50% similarity level, the microbial profiles of the eleven anaerobic digestates tested separated into just two groups, indicating a broad relative degree of similarity in terms of microbial numbers. Higher bacterial (16S) GCN was associated with low OM and C/N ratio in digestates.
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Affiliation(s)
- Janerson Jose Coelho
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
| | - Maria Luz Prieto
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
| | - Aoife Hennessy
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
| | - Imelda Casey
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
| | - Tony Woodcock
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
| | - Nabla Kennedy
- Eco-Innovation Research Centre, Department of Science, Waterford Institute of Technology, Waterford, Ireland
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He L, Simpson DJ, Gänzle MG. Detection of enterohaemorrhagic Escherichia coli in food by droplet digital PCR to detect simultaneous virulence factors in a single genome. Food Microbiol 2020; 90:103466. [DOI: 10.1016/j.fm.2020.103466] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Accepted: 01/12/2020] [Indexed: 02/06/2023]
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14
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Taparia T, Krijger M, Hodgetts J, Hendriks M, Elphinstone JG, van der Wolf J. Six Multiplex TaqMan TM-qPCR Assays for Quantitative Diagnostics of Pseudomonas Species Causative of Bacterial Blotch Diseases of Mushrooms. Front Microbiol 2020; 11:989. [PMID: 32523566 PMCID: PMC7261844 DOI: 10.3389/fmicb.2020.00989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/23/2020] [Indexed: 11/29/2022] Open
Abstract
Bacterial blotch is a group of economically important diseases of the common button mushroom (Agaricus bisporus). Once the pathogens are introduced to a farm, mesophilic growing conditions (that are optimum for mushroom production) result in severe and widespread secondary infections. Efficient, timely and quantitative detection of the pathogens is hence critical for the design of localized control strategies and prediction of disease risk. This study describes the development of real-time TaqManTM assays that allow molecular diagnosis of three currently prevalent bacterial blotch pathogens: “Pseudomonas gingeri,” Pseudomonas tolaasii and (as yet uncharacterized) Pseudomonas strains (belonging to Pseudomonas salomonii and Pseudomonas edaphica). For each pathogen, assays targeting specific DNA markers on two different loci, were developed for primary detection and secondary verification. All six developed assays showed high diagnostic specificity and sensitivity when tested against a panel of 63 Pseudomonas strains and 40 other plant pathogenic bacteria. The assays demonstrated good analytical performance indicated by linearity across calibration curve (>0.95), amplification efficiency (>90%) and magnitude of amplification signal (>2.1). The limits of detection were optimized for efficient quantification in bacterial cultures, symptomatic tissue, infected casing soil and water samples from mushroom farms. Each target assay was multiplexed with two additional assays. Xanthomonas campestris was detected as an extraction control, to account for loss of DNA during sample processing. And the total Pseudomonas population was detected, to quantify the proportion of pathogenic to beneficial Pseudomonas in the soil. This ratio is speculated to be an indicator for blotch outbreaks. The multiplexed assays were successfully validated and applied by routine testing of diseased mushrooms, peat sources, casing soils, and water from commercial production units.
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Affiliation(s)
- Tanvi Taparia
- Biointeractions and Plant Health, Wageningen University and Research, Wageningen, Netherlands.,Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, Netherlands
| | - Marjon Krijger
- Biointeractions and Plant Health, Wageningen University and Research, Wageningen, Netherlands
| | - Jennifer Hodgetts
- Department of Plant Protection, Fera Science Limited, York, United Kingdom
| | - Marc Hendriks
- Biointeractions and Plant Health, Wageningen University and Research, Wageningen, Netherlands
| | - John G Elphinstone
- Department of Plant Protection, Fera Science Limited, York, United Kingdom
| | - Jan van der Wolf
- Biointeractions and Plant Health, Wageningen University and Research, Wageningen, Netherlands
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15
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Sarengaowa, Hu W, Feng K, Jiang A, Xiu Z, Lao Y, Li Y, Long Y. An in situ-Synthesized Gene Chip for the Detection of Food-Borne Pathogens on Fresh-Cut Cantaloupe and Lettuce. Front Microbiol 2020; 10:3089. [PMID: 32117079 PMCID: PMC7012807 DOI: 10.3389/fmicb.2019.03089] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/20/2019] [Indexed: 02/04/2023] Open
Abstract
Fresh foods are vulnerable to foodborne pathogens which cause foodborne illness and endanger people's life and safety. The rapid detection of foodborne pathogens is crucial for food safety surveillance. An in situ-synthesized gene chip for the detection of foodborne pathogens on fresh-cut fruits and vegetables was developed. The target genes were identified and screened by comparing the specific sequences of Salmonella Typhimurium, Vibrio parahemolyticus, Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7 from the National Center for Biotechnology Information database. Tiling array probes were designed to target selected genes in an optimized hybridization system. A total of 141 specific probes were selected from 3,227 hybridization probes, comprising 26 L. monocytogenes, 24 S. aureus, 25 E. coli O157:H7, 20 Salmonella Typhimurium, and 46 V. parahemolyticus probes that are unique to this study. The optimized assay had strong amplification signals and high accuracy. The detection limit for the five target pathogens on fresh-cut cantaloupe and lettuce was approximately 3 log cfu/g without culturing and with a detection time of 24 h. The detection technology established in this study can rapidly detect and monitor the foodborne pathogens on fresh-cut fruits and vegetables throughout the logistical distribution chain, i.e., processing, cleaning, fresh-cutting, packaging, storage, transport, and sale, and represents a valuable technology that support the safety of fresh agricultural products.
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Affiliation(s)
- Sarengaowa
- School of Bioengineering, Dalian University of Technology, Dalian, China
- College of Life Science, Dalian Minzu University, Dalian, China
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian, China
| | - Wenzhong Hu
- College of Life Science, Dalian Minzu University, Dalian, China
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian, China
| | - Ke Feng
- College of Life Science, Dalian Minzu University, Dalian, China
| | - Aili Jiang
- College of Life Science, Dalian Minzu University, Dalian, China
- Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian, China
| | - Zhilong Xiu
- School of Bioengineering, Dalian University of Technology, Dalian, China
| | - Ying Lao
- College of Life Science, Dalian Minzu University, Dalian, China
| | - Yuanzheng Li
- College of Life Science, Dalian Minzu University, Dalian, China
| | - Ya Long
- College of Life Science, Dalian Minzu University, Dalian, China
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16
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On resolving ambiguities in microbial community analysis of partial nitritation anammox reactors. Sci Rep 2019; 9:6954. [PMID: 31061389 PMCID: PMC6502876 DOI: 10.1038/s41598-019-42882-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 04/11/2019] [Indexed: 11/08/2022] Open
Abstract
PCR-based methods have caused a surge for integration of eco-physiological approaches into research on partial nitritation anammox (PNA). However, a lack of rigorous standards for molecular analyses resulted in widespread data misinterpretation and consequently lack of consensus. Data consistency and accuracy strongly depend on the primer selection and data interpretation. An in-silico evaluation of 16S rRNA gene eubacterial primers used in PNA studies from the last ten years unraveled the difficulty of comparing ecological data from different studies due to a variation in the coverage of these primers. Our 16S amplicon sequencing approach, which includes parallel sequencing of six 16S rRNA hypervariable regions, showed that there is no perfect hypervariable region for PNA microbial communities. Using qPCR analysis, we emphasize the significance of primer choice for quantification and caution with data interpretation. We also provide a framework for PCR based analyses that will improve and assist to objectively interpret and compare such results.
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17
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Noviyanti F, Hosotani Y, Koseki S, Inatsu Y, Kawasaki S. Predictive Modeling for the Growth ofSalmonellaEnteritidis in Chicken Juice by Real-Time Polymerase Chain Reaction. Foodborne Pathog Dis 2018; 15:406-412. [DOI: 10.1089/fpd.2017.2392] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Fia Noviyanti
- Tsukuba Life Science Innovation, University of Tsukuba, Tsukuba, Japan
| | - Yukie Hosotani
- Division of Food Safety Research, Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Shigenobu Koseki
- Research Faculty of Agriculture, Hokkaido University, Hokkaido, Japan
| | - Yasuhiro Inatsu
- Division of Food Safety Research, Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Susumu Kawasaki
- Tsukuba Life Science Innovation, University of Tsukuba, Tsukuba, Japan
- Division of Food Safety Research, Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Japan
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18
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Kwon SJ, Kim D, Lee I, Nam J, Kim J, Dordick JS. Sensitive multiplex detection of whole bacteria using self-assembled cell binding domain complexes. Anal Chim Acta 2018; 1030:156-165. [PMID: 30032765 DOI: 10.1016/j.aca.2018.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 04/14/2018] [Accepted: 05/02/2018] [Indexed: 11/29/2022]
Abstract
Detecting bacterial cells at low levels is critical in public health, the food industry and first response. Current processes typically involve laborious cell lysis and genomic DNA extraction to achieve 100-1000 CFU mL-1 levels for detecting gram-positive bacteria. As an alternative to DNA-based methods, cell wall binding domains (CBDs) derived from lysins having a modular structure with an N-terminal catalytic domain and a C-terminal CBD, can be used to detect bacterial pathogens as a result of their exceptionally specific binding to target bacteria with great avidity. We have developed a highly sensitive method for multiplex detection of whole bacterial cells using self-assembled CBD complexes. Self-assembled CBD-SA-reporter complexes were generated using streptavidin (SA), biotin-CBDs, and biotinylated reporters, such as glucose oxidase (GOx) and specific DNA sequences. The simultaneous detection of three test bacteria, Staphylococcus aureus, Bacillus anthracis-Sterne, and Listeria innocua cells in PBS could be accomplished with a 96-well plate-based sandwich method using CBD-SA-GOx complex-coupled spectrophotometric assay to achieve a detection limit of >100 CFU mL-1. To achieve greater detection sensitivity, we used CBD-SA-DNA complexes and qPCR of specific DNA barcodes selectively bound to the surface of target bacterial cells, which resulted in a detection sensitivity as low as 1-10 CFU mL-1 without cross-reactivity. This sensitive multiplex detection of bacterial pathogens using both CBD-SA-GOx and CBD-SA-DNA complexes has the potential to be quickly combined with point-of-care compatible diagnostics for the rapid detection of pathogens in test samples.
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Affiliation(s)
- Seok-Joon Kwon
- Department of Chemical and Biological Engineering, Center for Biotechnology & Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Domyoung Kim
- Department of Chemical and Biological Engineering, Center for Biotechnology & Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Inseon Lee
- Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jahyun Nam
- Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jungbae Kim
- Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
| | - Jonathan S Dordick
- Department of Chemical and Biological Engineering, Center for Biotechnology & Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.
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19
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Xue J, Feng Y. Determination of adsorption and desorption of DNA molecules on freshwater and marine sediments. J Appl Microbiol 2018; 124:1480-1492. [DOI: 10.1111/jam.13739] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/30/2018] [Accepted: 02/15/2018] [Indexed: 01/30/2023]
Affiliation(s)
- J. Xue
- Department of Crop, Soil and Environmental Sciences; Auburn University; Auburn AL USA
| | - Y. Feng
- Department of Crop, Soil and Environmental Sciences; Auburn University; Auburn AL USA
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20
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Bonardi S, Bruini I, Bolzoni L, Cozzolino P, Pierantoni M, Brindani F, Bellotti P, Renzi M, Pongolini S. Assessment of Salmonella survival in dry-cured Italian salami. Int J Food Microbiol 2017; 262:99-106. [DOI: 10.1016/j.ijfoodmicro.2017.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 08/10/2017] [Accepted: 09/24/2017] [Indexed: 01/26/2023]
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21
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Precision food safety: A systems approach to food safety facilitated by genomics tools. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.06.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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22
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Comparison of EMA-, PMA- and DNase qPCR for the determination of microbial cell viability. Appl Microbiol Biotechnol 2017; 101:7371-7383. [PMID: 28875372 DOI: 10.1007/s00253-017-8471-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/21/2017] [Accepted: 08/03/2017] [Indexed: 01/13/2023]
Abstract
Ethidium monoazide (EMA) quantitative polymerase chain reaction (qPCR), propidium monoazide (PMA)-qPCR and DNase treatment in combination with qPCR were compared for the determination of microbial cell viability. Additionally, varying EMA and PMA concentrations were analysed to determine which dye and concentration allowed for the optimal identification of viable cells. Viable, heat treated (70 °C for 15 min) and autoclaved cultures of Legionella pneumophila, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Enterococcus faecalis were utilised in the respective viability assays. Analysis of the viable and heat-treated samples indicated that variable log reductions were recorded for both EMA [log reductions ranging from 0.01 to 2.71 (viable) and 0.27 to 2.85 (heat treated)], PMA [log reductions ranging from 0.06 to 1.02 (viable) and 0.62 to 2.46 (heat treated)] and DNase treatment [log reductions ranging from 0.06 to 0.82 (viable) and 0.70 to 2.91 (heat treated)], in comparison to the no viability treatment controls. Based on the results obtained, 6 μM EMA and 50 μM PMA were identified as the optimal dye concentrations as low log reductions were recorded (viable and heat-treated samples) in comparison to the no viability treatment control. In addition, the results recorded for the 6 μM EMA concentration were comparable to the results obtained for both the 50 μM PMA and the DNase treatment. The use of EMA-qPCR (6 μM) may therefore allow for the rapid identification and quantification of multiple intact opportunistic pathogens in water sources, which would benefit routine water quality monitoring following disinfection treatment.
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Abstract
Since the Human Genome Project completed in 2000, the sequencing of the first genome, massive progress has been made by medical science in the early diagnosis and personalized therapies based on nucleic acids (NA) analysis. To allow the extensive use of these molecular methods in medical practice, scientific research is nowadays strongly focusing on the development of new miniaturized and easy-to-use technologies and devices allowing fast and low cost NA analysis in decentralized environments. It is now the era of so-called genetic "Point-of-Care" (PoC). These systems must integrate and automate all steps necessary for molecular analysis such as sample preparation (extraction and purification of NA) and detection based on PCR (Polymerase Chain Reaction) technology in order to perform, by unskilled personnel, in vitro genetic analysis near the patient (in hospital, in the physician office, clinic, or home), with rapid answers and low cost. In this review, the recent advances in genetic PoC technologies are discussed, including the extraction and PCR amplification chemistry suitable for PoC use and the new frontiers of research in this field.
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Affiliation(s)
| | - Sabrina Conoci
- STMicroelectronics, Stradale Primosole 50, 95121 Catania, Italy
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24
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Quinn RA, Whiteson K, Lim YW, Zhao J, Conrad D, LiPuma JJ, Rohwer F, Widder S. Ecological networking of cystic fibrosis lung infections. NPJ Biofilms Microbiomes 2016; 2:4. [PMID: 28649398 PMCID: PMC5460249 DOI: 10.1038/s41522-016-0002-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 07/13/2016] [Accepted: 07/27/2016] [Indexed: 11/22/2022] Open
Abstract
In the context of a polymicrobial infection, treating a specific pathogen poses challenges because of unknown consequences on other members of the community. The presence of ecological interactions between microbes can change their physiology and response to treatment. For example, in the cystic fibrosis lung polymicrobial infection, antimicrobial susceptibility testing on clinical isolates is often not predictive of antibiotic efficacy. Novel approaches are needed to identify the interrelationships within the microbial community to better predict treatment outcomes. Here we used an ecological networking approach on the cystic fibrosis lung microbiome characterized using 16S rRNA gene sequencing and metagenomics. This analysis showed that the community is separated into three interaction groups: Gram-positive anaerobes, Pseudomonas aeruginosa, and Staphylococcus aureus. The P. aeruginosa and S. aureus groups both anti-correlate with the anaerobic group, indicating a functional antagonism. When patients are clinically stable, these major groupings were also stable, however, during exacerbation, these communities fragment. Co-occurrence networking of functional modules annotated from metagenomics data supports that the underlying taxonomic structure is driven by differences in the core metabolism of the groups. Topological analysis of the functional network identified the non-mevalonate pathway of isoprenoid biosynthesis as a keystone for the microbial community, which can be targeted with the antibiotic fosmidomycin. This study uses ecological theory to identify novel treatment approaches against a polymicrobial disease with more predictable outcomes.
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Affiliation(s)
- Robert A Quinn
- Department of Biology, San Diego State University, San Diego, CA 92182 USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093 USA
| | - Katrine Whiteson
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA 92697 USA
| | - Yan Wei Lim
- Department of Biology, San Diego State University, San Diego, CA 92182 USA
| | - Jiangchao Zhao
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI 48109 USA
- Division of Agriculture, Department of Animal Science, University of Arkansas, Fayetteville, AR 72701 USA
| | - Douglas Conrad
- Department of Medicine, University of California at San Diego, La Jolla, CA 92037 USA
| | - John J LiPuma
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, CA 92182 USA
| | - Stefanie Widder
- CUBE, Department of Microbiology and Ecosystem Science, University of Vienna, Althanstr.14 A-1090, Vienna, Austria
- CeMM - Research Center, for Molecular Medicine of the Austrian Academy of Sciences, Lazarettg, 14, A-1090 Vienna, Austria
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25
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Petsios S, Fredriksson-Ahomaa M, Sakkas H, Papadopoulou C. Conventional and molecular methods used in the detection and subtyping of Yersinia enterocolitica in food. Int J Food Microbiol 2016; 237:55-72. [DOI: 10.1016/j.ijfoodmicro.2016.08.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 07/28/2016] [Accepted: 08/11/2016] [Indexed: 01/08/2023]
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26
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Towards the production of reliable quantitative microbiological data for risk assessment: Direct quantification of Campylobacter in naturally infected chicken fecal samples using selective culture and real-time PCR. Food Control 2015. [DOI: 10.1016/j.foodcont.2015.02.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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27
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Alcaine SD, Tilton L, Serrano MAC, Wang M, Vachet RW, Nugen SR. Phage-protease-peptide: a novel trifecta enabling multiplex detection of viable bacterial pathogens. Appl Microbiol Biotechnol 2015; 99:8177-85. [PMID: 26245682 DOI: 10.1007/s00253-015-6867-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/12/2015] [Accepted: 07/15/2015] [Indexed: 11/27/2022]
Abstract
Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.
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Affiliation(s)
- S D Alcaine
- Department of Food Science, University of Massachusetts, 246 Chenoweth Laboratory, 102 Holdsworth Way, Amherst, MA, 01003, USA
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28
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Quinn RA, Whiteson K, Lim YW, Salamon P, Bailey B, Mienardi S, Sanchez SE, Blake D, Conrad D, Rohwer F. A Winogradsky-based culture system shows an association between microbial fermentation and cystic fibrosis exacerbation. THE ISME JOURNAL 2015; 9:1024-38. [PMID: 25514533 PMCID: PMC4817692 DOI: 10.1038/ismej.2014.234] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/24/2014] [Accepted: 11/04/2014] [Indexed: 01/09/2023]
Abstract
There is a poor understanding of how the physiology of polymicrobial communities in cystic fibrosis (CF) lungs contributes to pulmonary exacerbations and lung function decline. In this study, a microbial culture system based on the principles of the Winogradsky column (WinCF system) was developed to study the physiology of CF microbes. The system used glass capillary tubes filled with artificial sputum medium to mimic a clogged airway bronchiole. Chemical indicators were added to observe microbial physiology within the tubes. Characterization of sputum samples from seven patients showed variation in pH, respiration, biofilm formation and gas production, indicating that the physiology of CF microbial communities varied among patients. Incubation of homogenized tissues from an explant CF lung mirrored responses of a Pseudomonas aeruginosa pure culture, supporting evidence that end-stage lungs are dominated by this pathogen. Longitudinal sputum samples taken through two exacerbation events in a single patient showed that a two-unit drop in pH and a 30% increase in gas production occurred in the tubes prior to exacerbation, which was reversed with antibiotic treatment. Microbial community profiles obtained through amplification and sequencing of the 16S rRNA gene showed that fermentative anaerobes became more abundant during exacerbation and were then reduced during treatment where P. aeruginosa became the dominant bacterium. Results from the WinCF experiments support the model where two functionally different CF microbial communities exist, the persistent Climax Community and the acute Attack Community. Fermentative anaerobes are hypothesized to be the core members of the Attack Community and production of acidic and gaseous products from fermentation may drive developing exacerbations. Treatment targeting the Attack Community may better resolve exacerbations and resulting lung damage.
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Affiliation(s)
- Robert A Quinn
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Katrine Whiteson
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Yan-Wei Lim
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Peter Salamon
- Department of Mathematics and Statistics, San Diego State University, San Diego, CA, USA
| | - Barbara Bailey
- Department of Mathematics and Statistics, San Diego State University, San Diego, CA, USA
| | - Simone Mienardi
- Department of Chemistry, University of California, Irvine, CA, USA
| | | | - Don Blake
- Department of Chemistry, University of California, Irvine, CA, USA
| | - Doug Conrad
- Department of Medicine, University of California, San Diego, CA, USA
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, CA, USA
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29
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Mirmajlessi SM, Destefanis M, Gottsberger RA, Mänd M, Loit E. PCR-based specific techniques used for detecting the most important pathogens on strawberry: a systematic review. Syst Rev 2015; 4:9. [PMID: 25588564 PMCID: PMC4320524 DOI: 10.1186/2046-4053-4-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 01/02/2015] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Strawberry diseases are a major limiting factor that severely impact plant agronomic performance. Regarding limitations of traditional techniques for detection of pathogens, researchers have developed specific DNA-based tests as sensitive and specific techniques. The aim of this review is to provide an overview of polymerase chain reaction (PCR)-based methods used for detection or quantification of the most widespread strawberry pathogens, such as Fusarium oxysporum f.sp. fragariae, Phytophthora fragariae, Colletotrichum acutatum, Verticillium dahliae, Botrytis cinerea, Macrophomina phaseolina, and Xanthomonas fragariae. An updated and detailed list of published PCR protocols is presented and discussed, aimed at facilitating access to information that could be particularly useful for diagnostic laboratories in order to develop a rapid, cost-effective, and reliable monitoring technique. METHODS The study design was a systematic review of PCR-based techniques used for detection and quantification of strawberry pathogens. Using appropriate subject headings, AGRICOLA, AGRIS, BASE, Biological Abstracts, CAB Abstracts, Google Scholar, Scopus, Web of Knowledge, and SpringerLink databases were searched from their inception up to April 2014. Two assessors independently reviewed the titles, abstracts, and full articles of all identified citations. Selected articles were included if one of the mentioned strawberry pathogens was investigated based on PCR methods, and a summary of pre-analytical requirements for PCR was provided. RESULTS A total of 259 titles and abstracts were reviewed, of which 22 full texts met all the inclusion criteria. Our systematic review identified ten different protocols for X. fragariae, eight for P. fragariae, four for B. cinerea, six for C. acutatum, three for V. dahlia, and only one for F. oxysporum. The accuracy and sensitivity of PCR diagnostic methods is the focus of most studies included in this review. However, a large proportion of errors in laboratories occur in the pre-analytical phase of the testing process. Due to heterogeneity, results could not be meta-analyzed. CONCLUSIONS From a systematic review of the currently available published literature, effective detection assays to detect the major strawberry pathogens have been developed. These assays can function as a basis for clinical labs, regulatory personnel, and other diagnosticians to adapt or implement for detection of these six important strawberry pathogens.
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Affiliation(s)
- Seyed Mahyar Mirmajlessi
- />Department of Field Crops and Grassland Husbandry, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Marialaura Destefanis
- />Pesticides, Plant Health and Seed Testing Laboratories, Department of Agriculture, Food and the Marine, Backweston Campus, Celbridge, Co. Kildare Ireland
| | - Richard Alexander Gottsberger
- />Department for Molecular Diagnostics of Plant Diseases, Institute for Sustainable Plant Production, Austrian Agency for Health and Food Safety (AGES), Vienna, Austria
| | - Marika Mänd
- />Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Evelin Loit
- />Department of Field Crops and Grassland Husbandry, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
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30
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Alcaine SD, Pacitto D, Sela DA, Nugen SR. Phage & phosphatase: a novel phage-based probe for rapid, multi-platform detection of bacteria. Analyst 2015; 140:7629-36. [DOI: 10.1039/c5an01181g] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A bacteriophage-based biosensing platform forE. coliis proposed. The bacteriophage T7 was genetically engineered to carry the alkaline phosphatase genephoA. The overexpression of the gene was quantified with colorimetric, fluorescent, and chemiluminescent methods.
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Affiliation(s)
- S. D. Alcaine
- Department of Food Science
- University of Massachusetts
- Amherst
- USA
| | - D. Pacitto
- Department of Microbiology
- University of Massachusetts
- Amherst
- USA
| | - D. A. Sela
- Department of Food Science
- University of Massachusetts
- Amherst
- USA
- Department of Microbiology
| | - S. R. Nugen
- Department of Food Science
- University of Massachusetts
- Amherst
- USA
- Department of Microbiology
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31
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Barbau-Piednoir E, Mahillon J, Pillyser J, Coucke W, Roosens NH, Botteldoorn N. Evaluation of viability-qPCR detection system on viable and dead Salmonella serovar Enteritidis. J Microbiol Methods 2014; 103:131-7. [DOI: 10.1016/j.mimet.2014.06.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/02/2014] [Accepted: 06/02/2014] [Indexed: 11/25/2022]
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32
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Fusco V, Quero GM. Culture-Dependent and Culture-Independent Nucleic-Acid-Based Methods Used in the Microbial Safety Assessment of Milk and Dairy Products. Compr Rev Food Sci Food Saf 2014; 13:493-537. [DOI: 10.1111/1541-4337.12074] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/08/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Vincenzina Fusco
- Nal. Research Council of Italy; Inst. of Sciences of Food Production (CNR-ISPA); Bari Italy
| | - Grazia Marina Quero
- Nal. Research Council of Italy; Inst. of Sciences of Food Production (CNR-ISPA); Bari Italy
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33
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Ceuppens S, Li D, Uyttendaele M, Renault P, Ross P, Ranst MV, Cocolin L, Donaghy J. Molecular Methods in Food Safety Microbiology: Interpretation and Implications of Nucleic Acid Detection. Compr Rev Food Sci Food Saf 2014; 13:551-577. [DOI: 10.1111/1541-4337.12072] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/09/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Siele Ceuppens
- Faculty of Bioscience Engineering; Laboratory of Food Microbiology and Food Preservation (LFMFP); Dept. of Food Safety and Food Quality; Ghent Univ.; Ghent Belgium
| | - Dan Li
- Faculty of Bioscience Engineering; Laboratory of Food Microbiology and Food Preservation (LFMFP); Dept. of Food Safety and Food Quality; Ghent Univ.; Ghent Belgium
| | - Mieke Uyttendaele
- Faculty of Bioscience Engineering; Laboratory of Food Microbiology and Food Preservation (LFMFP); Dept. of Food Safety and Food Quality; Ghent Univ.; Ghent Belgium
| | - Pierre Renault
- Inst. Scientifique de Recherche Agronomique (INRA); France
| | - Paul Ross
- Moorepark Biotechnology Centre; Teagasc; Moorepark; Fermoy Co. Cork Ireland
| | | | - Luca Cocolin
- Dept. of Agricultural; Forest and Food Sciences; Univ. of Torino; Grugliasco Torino Italy
| | - John Donaghy
- Food Safety Microbiology Group; Nestle Research Center; Lausanne Switzerland
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Abstract
The aim of this work was to present selected data regarding traditional and modern methods for C. botulinum and its toxins detection. In this article, methods based on culturing techniques, mouse bioassay, immunological techniques, chromatography and PCR, PFGE, RFLP, AFLP are described. The mentioned techniques were evaluated considering their usefulness in the samples examination, genotyping of strains and the diagnostics of botulism.
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35
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Gordillo R, Rodríguez A, Werning ML, Bermúdez E, Rodríguez M. Quantification of viable Escherichia coli O157:H7 in meat products by duplex real-time PCR assays. Meat Sci 2014; 96:964-70. [DOI: 10.1016/j.meatsci.2013.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 05/03/2013] [Accepted: 10/12/2013] [Indexed: 01/04/2023]
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36
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Li M, Zhao G, Liu J, Gao X, Zhang Q. Effect of Different Heat Treatments on the Degradation of S
almonella
Nucleic Acid. J Food Saf 2013. [DOI: 10.1111/jfs.12086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miaoyun Li
- Henan Key Lab of Meat Processing and Quality Safety Control; Henan Agricultural University; Zhengzhou 450002 China
| | - Gaiming Zhao
- Henan Key Lab of Meat Processing and Quality Safety Control; Henan Agricultural University; Zhengzhou 450002 China
| | - Jie Liu
- Henan Key Lab of Meat Processing and Quality Safety Control; Henan Agricultural University; Zhengzhou 450002 China
| | - Xiaoping Gao
- Henan Key Lab of Meat Processing and Quality Safety Control; Henan Agricultural University; Zhengzhou 450002 China
| | - Qiuhui Zhang
- Henan Key Lab of Meat Processing and Quality Safety Control; Henan Agricultural University; Zhengzhou 450002 China
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Schelin J, Andersson G, Vigre H, Norling B, Häggblom P, Hoorfar J, Rådström P, Löfström C. Evaluation of pre-PCR processing approaches for enumeration of Salmonella enterica
in naturally contaminated animal feed. J Appl Microbiol 2013; 116:167-78. [DOI: 10.1111/jam.12337] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/09/2013] [Accepted: 08/27/2013] [Indexed: 11/29/2022]
Affiliation(s)
- J. Schelin
- Applied Microbiology; Department of Chemistry; Lund University; Lund Sweden
| | - G. Andersson
- Department of Chemistry; Environment and Feed hygiene; National Veterinary Institute (SVA); Uppsala Sweden
| | - H. Vigre
- National Food Institute; Technical University of Denmark; Søborg Denmark
| | - B. Norling
- Quintessence Research AB (QRAB); Alunda Sweden
| | - P. Häggblom
- Department of Chemistry; Environment and Feed hygiene; National Veterinary Institute (SVA); Uppsala Sweden
| | - J. Hoorfar
- National Food Institute; Technical University of Denmark; Søborg Denmark
| | - P. Rådström
- Applied Microbiology; Department of Chemistry; Lund University; Lund Sweden
| | - C. Löfström
- National Food Institute; Technical University of Denmark; Søborg Denmark
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38
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Garcia AB, Kamara JN, Vigre H, Hoorfar J, Josefsen MH. Direct Quantification of Campylobacter jejuni in Chicken Fecal Samples Using Real-Time PCR: Evaluation of Six Rapid DNA Extraction Methods. FOOD ANAL METHOD 2013. [DOI: 10.1007/s12161-013-9685-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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39
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Frausto HSEG, Alves J, Oliveira TCRMD. Evaluation of the BAX® system for the detection of Salmonella spp. in naturally contaminated chicken meat. FOOD SCIENCE AND TECHNOLOGY 2013. [DOI: 10.1590/s0101-20612013005000056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Harissa Silvério El Ghoz Frausto
- Universidade Estadual de Londrina, Brasil; Setor de Microbiologia do Laboratório São Camilo de Análises de Alimentos e Água, Brasil
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40
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Eichmiller JJ, Hicks RE, Sadowsky MJ. Distribution of genetic markers of fecal pollution on a freshwater sandy shoreline in proximity to wastewater effluent. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3395-402. [PMID: 23473470 PMCID: PMC3629727 DOI: 10.1021/es305116c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Water, sand, and sediment from a Lake Superior harbor site continuously receiving wastewater effluent was sampled monthly for June to October 2010 and from May to September 2011. Understanding the dynamics of genetic markers of fecal bacteria in these matrices is essential to accurately characterizing health risks. Genetic markers for enterococci, total Bacteroides, and human-associated Bacteroides were measured in site-water, sand, and sediment and in final effluent by quantitative PCR. The similarity between the quantity of molecular markers in the water column and effluent indicated that the abundance of genetic markers in the water column was likely controlled by effluent inputs. Effluent turbidity was positively correlated (p ≤ 0.05) with AllBac and HF183 in final effluent and AllBac in the water column. In sand and sediment, Entero1 and AllBac were most abundant in the upper 1-3 cm depths, whereas HF183 was most abundant in the upper 1 cm of sand and at 7 cm in sediment. The AllBac and Entero1 markers were 1- and 2-orders of magnitude more abundant in sand and sediment relative to the water column per unit mass. These results indicate that sand and sediment may act as reservoirs for genetic markers of fecal pollution at some freshwater sites.
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Affiliation(s)
- Jessica J. Eichmiller
- Department of Soil, Water, and Climate, University of Minnesota, 1991 Upper Buford Circle, 438 BorH, St. Paul, MN 55108
- Department of Biology, University of Minnesota Duluth, 1035 Kirby Drive, SSB 207, Duluth, MN 55812
| | - Randall E. Hicks
- Department of Biology, University of Minnesota Duluth, 1035 Kirby Drive, SSB 207, Duluth, MN 55812
| | - Michael J. Sadowsky
- Department of Soil, Water, and Climate, University of Minnesota, 1991 Upper Buford Circle, 438 BorH, St. Paul, MN 55108
- BioTechnology Institute, University of Minnesota,1479 Gortner Ave., 140 Gortner Labs, St. Paul, MN 55108
- Corresponding author: Michael Sadowsky, Department of Soil, Water, and Climate, University of Minnesota, 439 Borlaug Hall, 1991 Upper Buford Drive, Saint Paul, MN 55108, Phone: (612) 624-2706, Fax: (612) 625-2208,
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41
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Development of a rapid real-time PCR method as a tool to quantify viable Photobacterium phosphoreum bacteria in salmon (Salmo salar) steaks. Appl Environ Microbiol 2013; 79:2612-9. [PMID: 23396343 DOI: 10.1128/aem.03677-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A specific real-time PCR quantification method combined with a propidium monoazide sample treatment step was developed to determine quantitatively the viable population of the Photobacterium phosphoreum species group in raw modified-atmosphere-packed salmon. Primers were designed to amplify a 350-bp fragment of the gyrase subunit B gene (gyrB) of P. phosphoreum. The specificity of the two primers was demonstrated by using purified DNA from 81 strains of 52 different bacterial species. When these primers were used for real-time PCR in pure culture, a good correlation (R(2) of 0.99) was obtained between this method and conventional enumeration on marine agar (MA). Quantification was linear over 5 log units as confirmed by using inoculated salmon samples. On naturally contaminated fresh salmon, the new real-time PCR method performed successfully with a quantification limit of 3 log CFU/g. A correlation coefficient (R(2)) of 0.963 was obtained between the PCR method and classic enumeration on MA, followed by identification of colonies (290 isolates identified by real-time PCR or by 16S rRNA gene sequencing). A good correlation with an R(2) of 0.940 was found between the new PCR method and an available specific conductance method for P. phosphoreum. This study presents a rapid tool for producing reliable quantitative data on viable P. phosphoreum bacteria in fresh salmon in 6 h. This new culture-independent method will be valuable for future fish inspection, the assessment of raw material quality in fish processing plants, and studies on the ecology of this important specific spoilage microorganism.
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42
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Guo X, Lin CS, Chen SH, Ye R, Wu VC. A piezoelectric immunosensor for specific capture and enrichment of viable pathogens by quartz crystal microbalance sensor, followed by detection with antibody-functionalized gold nanoparticles. Biosens Bioelectron 2012; 38:177-83. [DOI: 10.1016/j.bios.2012.05.024] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Revised: 05/17/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
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43
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Zhu RG, Li TP, Jia YF, Song LF. Quantitative study of viable Vibrio parahaemolyticus cells in raw seafood using propidium monoazide in combination with quantitative PCR. J Microbiol Methods 2012; 90:262-6. [DOI: 10.1016/j.mimet.2012.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 05/25/2012] [Accepted: 05/27/2012] [Indexed: 11/25/2022]
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44
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Barth VC, Cattani F, Ferreira CA, de Oliveira SD. Sodium chloride affects propidium monoazide action to distinguish viable cells. Anal Biochem 2012; 428:108-10. [DOI: 10.1016/j.ab.2012.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
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45
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Real-time PCR methodology for selective detection of viable Escherichia coli O157:H7 cells by targeting Z3276 as a genetic marker. Appl Environ Microbiol 2012; 78:5297-304. [PMID: 22635992 DOI: 10.1128/aem.00794-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The goal of this study was to develop a sensitive, specific, and accurate method for the selective detection of viable Escherichia coli O157:H7 cells in foods. A unique open reading frame (ORF), Z3276, was identified as a specific genetic marker for the detection of E. coli O157:H7. We developed a real-time PCR assay with primers and probe targeting ORF Z3276 and confirmed that this assay was sensitive and specific for E. coli O157:H7 strains (n = 298). Using this assay, we can detect amounts of genomic DNA of E. coli O157:H7 as low as a few CFU equivalents. Moreover, we have developed a new propidium monoazide (PMA)-real-time PCR protocol that allows for the clear differentiation of viable from dead cells. In addition, the protocol was adapted to a 96-well plate format for easy and consistent handling of a large number of samples. Amplification of DNA from PMA-treated dead cells was almost completely inhibited, in contrast to the virtually unaffected amplification of DNA from PMA-treated viable cells. With beef spiked simultaneously with 8 × 10(7) dead cells/g and 80 CFU viable cells/g, we were able to selectively detect viable E. coli O157:H7 cells with an 8-h enrichment. In conclusion, this PMA-real-time PCR assay offers a sensitive and specific means to selectively detect viable E. coli O157:H7 cells in spiked beef. It also has the potential for high-throughput selective detection of viable E. coli O157:H7 cells in other food matrices and, thus, will have an impact on the accurate microbiological and epidemiological monitoring of food safety and environmental sources.
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46
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Ye K, Zhang Q, Jiang Y, Xu X, Cao J, Zhou G. Rapid detection of viable Listeria monocytogenes in chilled pork by real-time reverse-transcriptase PCR. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.10.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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47
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Swab sample preparation and viable real-time PCR methodologies for the recovery of Escherichia coli, Staphylococcus aureus or Listeria monocytogenes from artificially contaminated food processing surfaces. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.09.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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48
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Chen Y, Fu B, Wang Y, Jiang Q, Liu H. Reactor performance and bacterial pathogen removal in response to sludge retention time in a mesophilic anaerobic digester treating sewage sludge. BIORESOURCE TECHNOLOGY 2012; 106:20-26. [PMID: 22197074 DOI: 10.1016/j.biortech.2011.11.093] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 11/22/2011] [Accepted: 11/24/2011] [Indexed: 05/28/2023]
Abstract
The effects of sludge retention time (SRT) on reactor performance and bacterial pathogen removal of sludge mesophilic anaerobic digestion (MAD) were investigated in a continuous stirred tank reactor. The average volatile solids removal remained around 20% and the biogas production rate varied from 100 to 132ml/ld. The MAD process was efficient to remove Salmonella sp. and Escherichia coli with removal efficiencies increased with SRT from 11d, 16d to 25d. However, the Shigella sp. removal was insignificant. The difference in the resistance of the three pathogens to sludge MAD process is helpful to the selection of pathogen indicators in the biosolids. Log reduction of pathogens determined by MPN was much higher than the data by quantitative PCR, suggesting the presence of viable but non-culturable pathogen cells. This study confirms that the control of appropriate SRT for sludge MAD should take both reactor performance and pathogen removal into account.
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Affiliation(s)
- Yan Chen
- Laboratory of Environmental Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China
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49
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The composition of Camembert cheese-ripening cultures modulates both mycelial growth and appearance. Appl Environ Microbiol 2012; 78:1813-9. [PMID: 22247164 DOI: 10.1128/aem.06645-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fungal microbiota of bloomy-rind cheeses, such as Camembert, forms a complex ecosystem that has not been well studied, and its monitoring during the ripening period remains a challenge. One limitation of enumerating yeasts and molds on traditional agar media is that hyphae are multicellular structures, and colonies on a petri dish rarely develop from single cells. In addition, fungi tend to rapidly invade agar surfaces, covering small yeast colonies and resulting in an underestimation of their number. In this study, we developed a real-time quantitative PCR (qPCR) method using TaqMan probes to quantify a mixed fungal community containing the most common dairy yeasts and molds: Penicillium camemberti, Geotrichum candidum, Debaryomyces hansenii, and Kluyveromyces lactis on soft-cheese model curds (SCMC). The qPCR method was optimized and validated on pure cultures and used to evaluate the growth dynamics of a ripening culture containing P. camemberti, G. candidum, and K. lactis on the surface of the SCMC during a 31-day ripening period. The results showed that P. camemberti and G. candidum quickly dominated the ecosystem, while K. lactis remained less abundant. When added to this ecosystem, D. hansenii completely inhibited the growth of K. lactis in addition to reducing the growth of the other fungi. This result was confirmed by the decrease in the mycelium biomass on SCMC. This study compares culture-dependent and qPCR methods to successfully quantify complex fungal microbiota on a model curd simulating Camembert-type cheese.
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Bui XT, Wolff A, Madsen M, Bang DD. Fate and Survival of Campylobacter coli in Swine Manure at Various Temperatures. Front Microbiol 2011; 2:262. [PMID: 22207868 PMCID: PMC3245958 DOI: 10.3389/fmicb.2011.00262] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/07/2011] [Indexed: 11/29/2022] Open
Abstract
Campylobacter coli is the most common Campylobacter species found in pig (95%), but the ability of this bacterium to survive in swine manure as well as the potential for causing human illness are poorly understood. We present here laboratory-scale experiments to investigate the effect of temperature on the survival of C. coli in spiked swine manure samples at temperatures from 4 to 52°C. The survival of C. coli during storage for 30 days was studied by three different methods: bacterial culture (plate counting), DNA qPCR, and mRNA RT-qPCR. The results indicate that C. coli could survive in swine manure up to 24 days at 4°C. At higher temperatures, this bacterium survived only 7 days (15°C) or 6 days (22°C) of storage. The survival of C. coli was extremely short (few hours) in samples incubated at 42 and 52°C. The results from the RT-qPCR method were consistent with the data from the bacterial culture method, indicating that it detected only viable C. coli cells, thus eliminating false-positive resulting from DNA from dead C. coli cells.
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Affiliation(s)
- Xuan Thanh Bui
- Laboratory of Applied Micro and Nanotechnology, National Veterinary Institute, Technical University of DenmarkAarhus N, Denmark
| | - Anders Wolff
- BioLabChip Group, Department of Micro and Nanotechnology, Technical University of DenmarkKongens Lyngby, Denmark
| | - Mogen Madsen
- Dianova, Technical University of DenmarkAarhus N, Denmark
| | - Dang Duong Bang
- Laboratory of Applied Micro and Nanotechnology, National Veterinary Institute, Technical University of DenmarkAarhus N, Denmark
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