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Bromberger B, Mester PJ. Rapid detection of Listeria monocytogenes in dairy products by a novel chemilumonogenic approach. Food Microbiol 2023; 109:104150. [DOI: 10.1016/j.fm.2022.104150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/03/2022] [Accepted: 09/16/2022] [Indexed: 11/29/2022]
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Zhong Y, Xu P, Zhong S, Ding J. A sequential decoding procedure for pooled quantitative measure. Seq Anal 2022. [DOI: 10.1080/07474946.2022.2043049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yunning Zhong
- School of Mathematics and Statistics, Fujian Normal University, Fuzhou, Fujian, China
| | - Ping Xu
- School of Mathematics and Statistics, Guangxi Normal University, Guilin, Guangxi, China
| | - Siming Zhong
- School of Mathematics and Statistics, Guangxi Normal University, Guilin, Guangxi, China
| | - Juan Ding
- School of Mathematics and Statistics, Guangxi Normal University, Guilin, Guangxi, China
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Surveillance of Listeria monocytogenes: Early Detection, Population Dynamics, and Quasimetagenomic Sequencing during Selective Enrichment. Appl Environ Microbiol 2021; 87:e0177421. [PMID: 34613762 PMCID: PMC8612253 DOI: 10.1128/aem.01774-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In this study, we addressed different aspects regarding the implementation of quasimetagenomic sequencing as a hybrid surveillance method in combination with enrichment for early detection of Listeria monocytogenes in the food industry. Different experimental enrichment cultures were used, comprising seven L. monocytogenes strains of different sequence types (STs), with and without a background microbiota community. To assess whether the proportions of the different STs changed over time during enrichment, the growth and population dynamics were assessed using dapE colony sequencing and dapE and 16S rRNA amplicon sequencing. There was a tendency of some STs to have a higher relative abundance during the late stage of enrichment when L. monocytogenes was enriched without background microbiota. When coenriched with background microbiota, the population dynamics of the different STs was more consistent over time. To evaluate the earliest possible time point during enrichment that allows the detection of L. monocytogenes and at the same time the generation of genetic information that enables an estimation regarding the strain diversity in a sample, quasimetagenomic sequencing was performed early during enrichment in the presence of the background microbiota using Oxford Nanopore Technologies Flongle and Illumina MiSeq sequencing. The application of multiple displacement amplification (MDA) enabled detection of L. monocytogenes (and the background microbiota) after only 4 h of enrichment using both applied sequencing approaches. The MiSeq sequencing data additionally enabled the prediction of cooccurring L. monocytogenes strains in the samples. IMPORTANCE We showed that a combination of a short primary enrichment combined with MDA and Nanopore sequencing can accelerate the traditional process of cultivation and identification of L. monocytogenes. The use of Illumina MiSeq sequencing additionally allowed us to predict the presence of cooccurring L. monocytogenes strains. Our results suggest quasimetagenomic sequencing is a valuable and promising hybrid surveillance tool for the food industry that enables faster identification of L. monocytogenes during early enrichment. Routine application of this approach could lead to more efficient and proactive actions in the food industry that prevent contamination and subsequent product recalls and food destruction, economic and reputational losses, and human listeriosis cases.
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Bilder CR, Tebbs JM, McMahan CS. Discussion on "Is group testing ready for prime-time in disease identification". Stat Med 2021; 40:3881-3886. [PMID: 34251038 PMCID: PMC8441930 DOI: 10.1002/sim.8988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 11/08/2022]
Affiliation(s)
- Christopher R Bilder
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Joshua M Tebbs
- Department of Statistics, University of South Carolina, Columbia, South Carolina, USA
| | - Christopher S McMahan
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, South Carolina, USA
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Bilder CR, Tebbs JM, McMahan CS. Informative array testing with multiplex assays. Stat Med 2021; 40:3021-3034. [PMID: 33763901 DOI: 10.1002/sim.8954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/12/2021] [Accepted: 03/01/2021] [Indexed: 11/07/2022]
Abstract
High-volume testing of clinical specimens for sexually transmitted diseases is performed frequently by a process known as group testing. This algorithmic process involves testing portions of specimens from separate individuals together as one unit (or "group") to detect diseases. Retesting is performed on groups that test positively in order to differentiate between positive and negative individual specimens. The overall goal is to use the least number of tests possible across all individuals without sacrificing diagnostic accuracy. One of the most efficient group testing algorithms is array testing. In its simplest form, specimens are arranged into a grid-like structure so that row and column groups can be formed. Positive-testing rows/columns indicate which specimens to retest. With the growing use of multiplex assays, the increasing number of diseases tested by these assays, and the availability of subject-specific risk information, opportunities exist to make this testing process even more efficient. We propose specific specimen arrangements within an array that can reduce the number of retests needed when compared with other array testing algorithms. We examine how to calculate operating characteristics, including the expected number of tests and the SD for the number of tests, and then subsequently find a best arrangement. Our methods are illustrated for chlamydia and gonorrhea detection with the Aptima Combo 2 Assay. We also provide R functions to make our research accessible to laboratories.
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Affiliation(s)
- Christopher R Bilder
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Joshua M Tebbs
- Department of Statistics, University of South Carolina, Columbia, South Carolina, USA
| | - Christopher S McMahan
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, South Carolina, USA
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How to Evaluate Non-Growing Cells-Current Strategies for Determining Antimicrobial Resistance of VBNC Bacteria. Antibiotics (Basel) 2021; 10:antibiotics10020115. [PMID: 33530321 PMCID: PMC7912045 DOI: 10.3390/antibiotics10020115] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022] Open
Abstract
Thanks to the achievements in sanitation, hygiene practices, and antibiotics, we have considerably improved in our ongoing battle against pathogenic bacteria. However, with our increasing knowledge about the complex bacterial lifestyles and cycles and their plethora of defense mechanisms, it is clear that the fight is far from over. One of these resistance mechanisms that has received increasing attention is the ability to enter a dormancy state termed viable but non-culturable (VBNC). Bacteria that enter the VBNC state, either through unfavorable environmental conditions or through potentially lethal stress, lose their ability to grow on standard enrichment media, but show a drastically increased tolerance against antimicrobials including antibiotics. The inability to utilize traditional culture-based methods represents a considerable experimental hurdle to investigate their increased antimicrobial resistance and impedes the development and evaluation of effective treatments or interventions against bacteria in the VBNC state. Although experimental approaches were developed to detect and quantify VBNCs, only a few have been utilized for antimicrobial resistance screening and this review aims to provide an overview of possible methodological approaches.
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Abstract
Quantitative PCR, if performed properly, is a highly sensitive and robust tool. Nevertheless, its application to the particular case of pathogen detection from foodstuffs necessitates special requirements for reliable results. Firstly, a robust analytical chain, involving sample preparation and DNA isolation with purification, is necessary to ensure optimal performance. Secondly, for reliable quantification of Listeria monocytogenes from food, reproducible controls for all steps of the analytical chain are needed, which can give quantitative information about the performance of each individual step of the detection chain. Ideally, each individual sample should include a so-called internal sample process control (ISPC) which passes through all steps of the analytical chain and is phenotypically similar to the target organism (in this case L. monocytogenes).This chapter describes the modular and rapid (3 h) sample preparation method "matrix lysis" for the quantification of L. monocytogenes from food and gives detailed information regarding the application of an ISPC based on the example of the L. monocytogenes Δ-prfA/+IAC strain.
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Affiliation(s)
- Patrick Mester
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
| | | | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
- Unit of Food Microbiology, Institute of Food Safety, Food Technology and Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria
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Implementation of the DEP-pooling approach for L. monocytogenes detection over 25-months by two diagnostic laboratories of an Austrian dairy company. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Fister S, Mester P, Witte AK, Sommer J, Schoder D, Rossmanith P. Part of the problem or the solution? Indiscriminate use of bacteriophages in the food industry can reduce their potential and impair growth-based detection methods. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.02.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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A Novel Method for Sampling and Long-Term Monitoring of Microbes That Uses Stickers of Plain Paper. Appl Environ Microbiol 2019; 85:AEM.00766-19. [PMID: 31126944 DOI: 10.1128/aem.00766-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 04/24/2019] [Indexed: 11/20/2022] Open
Abstract
Detection of pathogens is crucial in food production areas. While it is well established, swabbing as a state-of-the-art sampling method offers several drawbacks with respect to yield, standardization, overall handling, and long-term monitoring. This led us to develop and evaluate a method that is easier to use at a lower cost and that should be at least as sensitive. After evaluating sundry promising materials, we tested text-marking paper stickers for their suitability to take up and release Listeria monocytogenes with their nonsticky paper side over a 14-day time period using quantitative PCR. The recovery rate was similar to that in previous studies using conventional swabs, and we also confirmed the feasibility of pooling besides resilience to cleansing and disinfection. In a proof-of-concept experiment that sampled several locations, such as door handles, the occurrences of L. monocytogenes and Escherichia coli were determined. The results suggest that the presented sticker system might offer a promising cost-effective alternative sampling system with improved handling characteristics.IMPORTANCE As a ubiquitous bacterium, Listeria monocytogenes has a propensity to enter food production areas inadvertently via fomites such as door handles and switches. While the bacterium might not be in direct contact with the food products, knowing the microbial status of the surroundings is essential for risk assessment. Our investigation into a novel quantitative PCR (qPCR)-based sampling system with the highest sensitivity and ability to monitor over long periods of time, yet based on paper, proved to be cost-effective and reasonably convenient to handle.
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Sommer J, Trautner C, Witte AK, Fister S, Schoder D, Rossmanith P, Mester PJ. Don't Shut the Stable Door after the Phage Has Bolted-The Importance of Bacteriophage Inactivation in Food Environments. Viruses 2019; 11:E468. [PMID: 31121941 PMCID: PMC6563225 DOI: 10.3390/v11050468] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/05/2019] [Accepted: 05/17/2019] [Indexed: 12/11/2022] Open
Abstract
In recent years, a new potential measure against foodborne pathogenic bacteria was rediscovered-bacteriophages. However, despite all their advantages, in connection to their widespread application in the food industry, negative consequences such as an uncontrolled phage spread as well as a development of phage resistant bacteria can occur. These problems are mostly a result of long-term persistence of phages in the food production environment. As this topic has been neglected so far, this article reviews the current knowledge regarding the effectiveness of disinfectant strategies for phage inactivation and removal. For this purpose, the main commercial phage products, as well as their application fields are first discussed in terms of applicable inactivation strategies and legal regulations. Secondly, an overview of the effectiveness of disinfectants for bacteriophage inactivation in general and commercial phages in particular is given. Finally, this review outlines a possible strategy for users of commercial phage products in order to improve the effectiveness of phage inactivation and removal after application.
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Affiliation(s)
- Julia Sommer
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Christoph Trautner
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Anna Kristina Witte
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
- HTK Hygiene Technologie Kompetenzzentrum GmbH, Buger Str. 80, 96049 Bamberg, Germany.
| | - Susanne Fister
- Former member of Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Institute of Milk Hygiene, Milk Technology and Food Science, Department for Farm Animal and Public Veterinary Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Dagmar Schoder
- Unit of Food Microbiology, Institute of Food Safety, Food Technology and Veterinary Public Health, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Peter Rossmanith
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
- Unit of Food Microbiology, Institute of Food Safety, Food Technology and Veterinary Public Health, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Patrick-Julian Mester
- Christian Doppler Laboratory for Monitoring of Microbial Contaminants, Department for Farm Animal and Public Health in Veterinary Medicine, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
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Determination of Varying Group Sizes for Pooling Procedure. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2019; 2019:4381084. [PMID: 31065292 PMCID: PMC6466917 DOI: 10.1155/2019/4381084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 01/17/2019] [Accepted: 02/05/2019] [Indexed: 11/17/2022]
Abstract
Pooling is an attractive strategy in screening infected specimens, especially for rare diseases. An essential step of performing the pooled test is to determine the group size. Sometimes, equal group size is not appropriate due to population heterogeneity. In this case, varying group sizes are preferred and could be determined while individual information is available. In this study, we propose a sequential procedure to determine varying group sizes through fully utilizing available information. This procedure is data driven. Simulations show that it has good performance in estimating parameters.
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Witte AK, Leeb C, Pinior B, Mester P, Fister S, Bobal M, Schoder D, Rossmanith P. Influence of sampling and DNA extraction on 16S rRNA gene amplicon sequencing - Comparison of the bacterial community between two food processing plants. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2017.12.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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