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Codony F, Agustí G, Barreto L, Asensio D. Relevance of Secondary Enrichment in the Detection of Salmonella spp. in Food Samples by qPCR According to DIN 10135. J AOAC Int 2024; 107:371-374. [PMID: 38218726 DOI: 10.1093/jaoacint/qsae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/03/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024]
Abstract
BACKGROUND When detecting Salmonella spp. in food samples, unlike with culture-based procedures where there are solid standards, PCR techniques are generally dominated by commercial solutions, often backed by the conformity of reference organizations, and based on rigorous validation studies. The few independent standards that exist are not subject to revision and improvement to the same extent as the manufacturer's methods. Moreover, since commercial networks do not promote them, they are implemented less in everyday practice. The German standard DIN 10135 is an example of this. In this method, before PCR detection, a primary enrichment (16-20 h) followed by a secondary selective enrichment of at least 6 h is needed. Nevertheless, it allows the possibility of only applying the first step if evidence of their correct operation is provided. OBJECTIVE To evaluate how necessary is the secondary enrichment for DIN 10135 standard. METHODS Short and complete enrichment steps were compared in the context of the evaluation of the limit of detection for 11 types of food. Additionally, a blind assay was performed with 75 food samples. RESULTS The data show that a simple primary enrichment may be sufficient and that the second selective enrichment with the tested matrixes would not be strictly essential. The blind study obtained a 98.6% of trueness and precision of 100%. CONCLUSIONS At least for the end consumer products, a secondary enrichment of 6 h is not necessary for all the products tested. HIGHLIGHTS In the context of the DIN 10135 standard, the primary enrichment (16-20 h, 37 ± 1°C) can be enough for detecting Salmonella spp.
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Affiliation(s)
- Francesc Codony
- Laboratori d'Aigües de Mataró, Carrer Hèl·lade, 17-19, 08304 Mataró, Spain
| | - Gemma Agustí
- Reactivos Para Diagnóstico, S.L., Department of Quality Control, Polígono Industrial Mas d'En Cisa, Calle Josep Tura 9 H, 08181 Sentmenat, Barcelona, Spain
| | - Lina Barreto
- Reactivos Para Diagnóstico, S.L., Department of Quality Control, Polígono Industrial Mas d'En Cisa, Calle Josep Tura 9 H, 08181 Sentmenat, Barcelona, Spain
| | - Daniel Asensio
- Reactivos Para Diagnóstico, S.L., Department of Quality Control, Polígono Industrial Mas d'En Cisa, Calle Josep Tura 9 H, 08181 Sentmenat, Barcelona, Spain
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2
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Aladhadh M. A Review of Modern Methods for the Detection of Foodborne Pathogens. Microorganisms 2023; 11:1111. [PMID: 37317085 DOI: 10.3390/microorganisms11051111] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 06/16/2023] Open
Abstract
Despite the recent advances in food preservation techniques and food safety, significant disease outbreaks linked to foodborne pathogens such as bacteria, fungi, and viruses still occur worldwide indicating that these pathogens still constitute significant risks to public health. Although extensive reviews of methods for foodborne pathogens detection exist, most are skewed towards bacteria despite the increasing relevance of other pathogens such as viruses. Therefore, this review of foodborne pathogen detection methods is holistic, focusing on pathogenic bacteria, fungi, and viruses. This review has shown that culture-based methods allied with new approaches are beneficial for the detection of foodborne pathogens. The current application of immunoassay methods, especially for bacterial and fungal toxins detection in foods, are reviewed. The use and benefits of nucleic acid-based PCR methods and next-generation sequencing-based methods for bacterial, fungal, and viral pathogens' detection and their toxins in foods are also reviewed. This review has, therefore, shown that different modern methods exist for the detection of current and emerging foodborne bacterial, fungal, and viral pathogens. It provides further evidence that the full utilization of these tools can lead to early detection and control of foodborne diseases, enhancing public health and reducing the frequency of disease outbreaks.
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Affiliation(s)
- Mohammed Aladhadh
- Department of Food Science and Human Nutrition, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah 51452, Saudi Arabia
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3
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Thilakarathna SH, Stokowski T, Chui L. An Improved Real-Time Viability PCR Assay to Detect Salmonella in a Culture-Independent Era. Int J Mol Sci 2022; 23:ijms232314708. [PMID: 36499040 PMCID: PMC9738789 DOI: 10.3390/ijms232314708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022] Open
Abstract
Viability PCR (vPCR) uses a DNA intercalating dye to irreversibly bind double-stranded DNA from organisms with compromised cell membranes. This allows the selective amplification of DNA from intact cells. An optimized vPCR protocol should minimize false positives (DNA from compromised cells not fully removed) and false negatives (live cell DNA bound by the dye). We aimed to optimize a vPCR protocol using PMAxx™ as the intercalating agent and Salmonella Enteritidis as the target organism. To do this, we studied (1) single vs. sequential PMAxx™ addition; (2) a wash step post-PMAxx™ treatment; (3) a change of tube post-treatment before DNA extraction. The single vs. sequential PMAxx™ addition showed no difference. Results signified that PMAxx™ potentially attached to polypropylene tube walls and bound the released DNA from PMA-treated live cells when lysed in the same tube. A wash step was ineffective but transfer of the treated live cells to a new tube minimized these false-negative results. Our optimized protocol eliminated 108 CFU/mL heat-killed cell DNA in the presence of different live cell dilutions without compromising the amplification of the live cells, minimizing false positives. With further improvements, vPCR has great potential as a culture-independent diagnostic tool.
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Affiliation(s)
- Surangi H. Thilakarathna
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 1C9, Canada
| | - Taryn Stokowski
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 1C9, Canada
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 1C9, Canada
- Alberta Precision Laboratories, Public Health Laboratory (ProvLab), Edmonton, AB T6G 2J2, Canada
- Correspondence:
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4
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Wang H, Wagnon R, Moreno D, Timilsina S, Jones J, Vallad G, Turechek WW. A Long-Amplicon Viability-qPCR Test for Quantifying Living Pathogens that Cause Bacterial Spot in Tomato Seed. PLANT DISEASE 2022; 106:1474-1485. [PMID: 34894749 DOI: 10.1094/pdis-11-21-2509-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bacterial spot is one of the most serious diseases of tomato. It is caused by four species of Xanthomonas: X. euvesicatoria, X. gardneri, X. perforans, and X. vesicatoria. Contaminated or infected seed can be a major source of inoculum for this disease. The use of certified pathogen-free seed is one of the primary management practices to reduce the inoculum load in commercial production. Current seed testing protocols rely mainly on plating the seed extract and conventional PCR; however, the plating method cannot detect viable but nonculturable cells, and the conventional PCR assay has limited capability to differentiate DNA extracted from viable or dead bacterial cells. To improve the sensitivity and specificity of the tomato seed testing method for bacterial spot pathogens, a long-amplicon quantitative PCR (qPCR) assay coupled with propidium monoazide (PMA-qPCR) was developed to quantify selectively the four pathogenic Xanthomonas species in tomato seed. The optimized PMA-qPCR procedure was evaluated on pure bacterial suspensions, bacteria-spiked seed extracts, and seed extracts of inoculated and naturally infected seed. A crude DNA extraction protocol also was developed, and PMA-qPCR with crude bacterial DNA extracts resulted in accurate quantification of 104 to 108 CFU/ml of viable bacteria when mixed with dead cells at concentrations as high as 107 CFU/ml in the seed extracts. With DNA purified from concentrated seed extracts, the PMA-qPCR assay was able to detect DNA of the target pathogens in seed samples spiked with ≥75 CFU/ml (about 0.5 CFU/seed) of the viable pathogens. Latent class analysis of the inoculated and naturally infected seed samples showed that the PMA-qPCR assay had greater sensitivity than plating the seed extracts on the semiselective modified Tween Medium B and CKTM media for all four target species. Being much faster and more sensitive than dilution plating, the PMA-qPCR assay has potential to be used as a standalone tool or in combination with the plating method to improve tomato seed testing and advance the production of clean seed.
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Affiliation(s)
- Hehe Wang
- EDISTO Research and Education Center, Clemson University, Blackville, SC 29817
| | - Rieanna Wagnon
- EDISTO Research and Education Center, Clemson University, Blackville, SC 29817
| | - Daniela Moreno
- EDISTO Research and Education Center, Clemson University, Blackville, SC 29817
| | | | | | - Gary Vallad
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598
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5
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Vural C, Diallo MM, Ozdemir G. Assessment of Comamonas testosteroni strain PT9 as a rapid phthalic acid degrader for industrial wastewaters. J Basic Microbiol 2021; 62:508-517. [PMID: 34596900 DOI: 10.1002/jobm.202100258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/31/2021] [Accepted: 09/11/2021] [Indexed: 11/06/2022]
Abstract
In this study, characterization of industry-borne Comamonas testosteroni strain PT9 isolate was performed by determining degradation ability on phthalic acid (PA). High-performance liquid chromatography analyses showed that strain PT9 completely degraded 102.94 mg/L of PA within 6 h. Viability polymerase chain reaction (vPCR) was performed with propidium monoazide treatment. vPCR showed that the PA has positively stimulated the cell growth during degradation. To consider the fate of PA, the proposed catalytic genes (ophA2, iphA2, tphA2, tphA3, pmdA, and pmdB) for the degradation pathways of PA isomers for C. testosteroni were screened in strain PT9. All genes except iphA2 were detected in strain PT9, and expression levels of related genes were analyzed by Real-Time PCR (qPCR).
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Affiliation(s)
- Caner Vural
- Department of Biology, Molecular Biology Section, Faculty of Science and Arts, Pamukkale University Kinikli Campus, Denizli, Turkey
| | - Mamadou M Diallo
- Department of Biology, Basic and Industrial Microbiology Section, Ege University, Izmir, Turkey
| | - Guven Ozdemir
- Department of Biology, Basic and Industrial Microbiology Section, Ege University, Izmir, Turkey
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6
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Shoults DC, Li Q, Petterson S, Rudko SP, Dlusskaya L, Leifels M, Scott C, Schlosser C, Ashbolt NJ. Pathogen performance testing of a natural swimming pool using a cocktail of microbiological surrogates and QMRA-derived management goals. JOURNAL OF WATER AND HEALTH 2021; 19:629-641. [PMID: 34371499 DOI: 10.2166/wh.2021.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in Germany and Austria. NSPs differ from swimming pools in that they utilize biological treatment processes based on wetland processes with no disinfection residual. However, data are missing on the specific log-reduction performance of NSPs to address enteric virus, bacteria, and parasitic protozoa removal considered necessary to meet the North American risk-based benchmark (<35 illnesses per 1,000 swimming events) set by the USEPA for voluntary swimming. In this study, we examined Canada's first NSP at Borden Park, Edmonton, Canada, to address the following three questions: (1) Given normal faecal shedding rates by bathers, what is the total log reduction (TLR) theoretically needed to meet the EPA benchmark? (2) what is the in-situ performance of the NSP based on spiking suitable microbial surrogates (MS2 coliphage, Enterococcus faecalis, and Saccharomyces cerevisiae [Baker's yeast])? and (3) how much time is required to reach acceptable bather risk levels under different representative volume-turnover rates? A reverse-quantitative microbial risk assessment (QMRA) revealed that of the four reference pathogens selected (Norovirus, Campylobacter, Cryptosporidium, and Giardia), only Norovirus was estimated to exceed the risk benchmark at the 50th, 75th, and 95th percentiles, while Campylobacter was the only other reference pathogen to exceed at the 95th percentile. Log-reduction values (LRVs) were similar to previous reports for bacterial indicators, and novel LRVs were estimated for the other two surrogates. A key finding was that more than 24 h treatment time would be necessary to provide acceptable bather protection following heavy bather use (378 bathers/day for main pool and 26 bathers/day for children's pool), due to the mixing dynamics of the treated water diluting out possible residual pool faecal contamination. The theoretical maximum number of people in the pool per day to be below USEPA's 35 gastro cases in 1,000 swimming events was 113, 47, and 8, at the 50th, 75th, and 95th percentiles. Further, the use of ultra-violet disinfection to the pool return flow had little effect on reducing the treatment time required.
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Affiliation(s)
- David C Shoults
- Centre for Water Resources Studies, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Qiaozhi Li
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Susan Petterson
- Water & Health Pty Ltd, North Sydney, NSW 2060, Australia; School of Medicine, Griffith University, Gold Coast, QLD 4222, Australia
| | - Sydney P Rudko
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Lena Dlusskaya
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Mats Leifels
- Singapore Centre of Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Canada
| | - Candis Scott
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail:
| | - Cyndi Schlosser
- Borden Park, City of Edmonton, Edmonton, Alberta T5B 4W8, Canada
| | - Nicholas J Ashbolt
- School of Public Health, University of Alberta, Edmonton, Alberta T6G 2G7, Canada E-mail: ; Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW 2480, Australia
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Hortelano I, Moreno MY, García-Hernández J, Ferrús MA. Optimization of pre- treatments with Propidium Monoazide and PEMAX™ before real-time quantitative PCR for detection and quantification of viable Helicobacter pylori cells. J Microbiol Methods 2021; 185:106223. [PMID: 33872638 DOI: 10.1016/j.mimet.2021.106223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/17/2022]
Abstract
Accurate detection of H. pylori in different environmental and clinical samples is essential for public health strtdudies. Now, a big effort is being made to design PCR methodologies that allow for the detection of viable and viable but non-culturable (VBNC) H. pylori cells, by achieving complete exclusion of dead cells amplification signals. The use of DNA intercalating dyes has been proposed. However, its efficacy is still not well determined. In this study, we aimed to test the suitability of PMA and PEMAX™ dyes used prior to qPCR for only detecting viable cells of H. pylori. Their efficiency was evaluated with cells submitted to different disinfection treatments and confirmed by the absence of growth on culture media and by LIVE/DEAD counts. Our results indicated that an incubation period of 5 min for both, PMA and PEMAX™, did not affect viable cells. Our study also demonstrated that results obtained by using intercalating dyes may vary depending on the cell stress conditions. In all dead cell's samples, both PMA and PEMAX™ pre-qPCR treatments decreased the amplification signal (>103 Genomic Units (GU)), although none of them allowed for its disappearance confirming that intercalating dyes, although useful for screening purposes, cannot be considered as universal viability markers. To investigate the applicability of the method specifically to detect H. pylori cells in environmental samples, PMA-qPCR was performed on samples containing the different morphological and viability states that H. pylori can acquire in environment. The optimized PMA-qPCR methodology showed to be useful to detect mostly (but not only) viable forms, regardless the morphological state of the cell.
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Affiliation(s)
- Irene Hortelano
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain.
| | - María Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain
| | | | - María Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, 46022, Valencia, Spain.
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8
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Baró A, Badosa E, Montesinos L, Feliu L, Planas M, Montesinos E, Bonaterra A. Screening and identification of BP100 peptide conjugates active against Xylella fastidiosa using a viability-qPCR method. BMC Microbiol 2020; 20:229. [PMID: 32727358 PMCID: PMC7392676 DOI: 10.1186/s12866-020-01915-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Background Xylella fastidiosa is one of the most harmful bacterial plant pathogens worldwide, causing a variety of diseases, with huge economic impact to agriculture and environment. Although it has been extensively studied, there are no therapeutic solutions to suppress disease development in infected plants. In this context, antimicrobial peptides represent promising alternatives to traditional compounds due to their activity against a wide range of plant pathogens, their low cytotoxicity, their mode of action that make resistance more difficult and their availability for being expressed in plants. Results Peptide conjugates derived from the lead peptide BP100 and fragments of cecropin, magainin or melittin were selected and tested against the plant pathogenic bacteria X. fastidiosa. In order to screen the activity of these antimicrobials, and due to the fastidious nature of the pathogen, a methodology consisting of a contact test coupled with the viability-quantitative PCR (v-qPCR) method was developed. The nucleic acid-binding dye PEMAX was used to selectively quantify viable cells by v-qPCR. In addition, the primer set XF16S-3 amplifying a 279 bp fragment was selected as the most suitable for v-qPCR. The performance of the method was assessed by comparing v-qPCR viable cells estimation with conventional qPCR and plate counting. When cells were treated with peptide conjugates derived from BP100, the observed differences between methods suggested that, in addition to cell death due to the lytic effect of the peptides, there was an induction of the viable but non-culturable state in cells. Notably, a contact test coupled to v-qPCR allowed fast and accurate screening of antimicrobial peptides, and led to the identification of new peptide conjugates active against X. fastidiosa. Conclusions Antimicrobial peptides active against X. fastidiosa have been identified using an optimized methodology that quantifies viable cells without a cultivation stage, avoiding underestimation or false negative detection of the pathogen due to the viable but non-culturable state, and overestimation of the viable population observed using qPCR. These findings provide new alternative compounds for being tested in planta for the control of X. fastidiosa, and a methodology that enables the fast screening of a large amount of antimicrobials against this plant pathogenic bacterium.
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Affiliation(s)
- Aina Baró
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Esther Badosa
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Laura Montesinos
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Lidia Feliu
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Marta Planas
- LIPPSO, Department of Chemistry, University of Girona, Girona, Spain
| | - Emilio Montesinos
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain
| | - Anna Bonaterra
- Laboratory of Plant Pathology, Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, Girona, Spain.
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Baymiev AK, Baymiev AK, Kuluev BR, Shvets KY, Yamidanov RS, Matniyazov RT, Chemeris DA, Zubov VV, Alekseev YI, Mavzyutov AR, Ivanenkov YA, Chemeris AV. Modern Approaches to Differentiation of Live and Dead Bacteria Using Selective Amplification of Nucleic Acids. Microbiology (Reading) 2020. [DOI: 10.1134/s0026261720010038] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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10
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Codony F, Dinh-Thanh M, Agustí G. Key Factors for Removing Bias in Viability PCR-Based Methods: A Review. Curr Microbiol 2019; 77:682-687. [DOI: 10.1007/s00284-019-01829-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/29/2019] [Indexed: 11/24/2022]
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Khammadov NI, Aleksandrova NM, Khammadova AV, Shuralev EA. Evaluation of the Effectiveness of Genetic Markers of Mycobacteria for Assessing the Disinfection Quality by Viability Real Time PCR. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00654-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Spiking a Silty-Sand Reference Soil with Bacterial DNA: Limits and Pitfalls in the Discrimination of Live and Dead Cells When Applying Ethidium Monoazide (EMA) Treatment. Curr Microbiol 2019; 76:1425-1434. [PMID: 31552450 PMCID: PMC6817739 DOI: 10.1007/s00284-019-01772-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/30/2019] [Accepted: 09/11/2019] [Indexed: 10/28/2022]
Abstract
In the present study, EMA (ethidium monoazide) treatment was applied to a silty-sand reference soil prior to DNA extraction to enable a differentiation between dead and living cells. For this purpose, a reference soil was spiked with Listeria monocytogenes cells or cell equivalents, respectively. With the purpose of evaluating optimum treatment conditions, different EMA concentrations have been tested. However, the results remained largely inconclusive. Furthermore, varied dark incubation periods allowing EMA to penetrate dead cells did not allow the selective removal of DNA from membrane-compromised cells in downstream analyses. In contrast to undiluted soil, an effect of EMA treatment during DNA extraction could be observed when using a 1:10 dilution of the reference soil; however, the effect has not been sufficiently selective to act on heat-treated cells only. Although the application of EMA to soil requires further evaluation, the procedure harbors future potential for improving DNA-based approaches in microbial ecology studies.
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Paniel N, Noguer T. Detection of Salmonella in Food Matrices, from Conventional Methods to Recent Aptamer-Sensing Technologies. Foods 2019; 8:E371. [PMID: 31480504 PMCID: PMC6770675 DOI: 10.3390/foods8090371] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 01/01/2023] Open
Abstract
Rapid detection of the foodborne pathogen Salmonella in food processing is of crucial importance to prevent food outbreaks and to ensure consumer safety. Detection and quantification of Salmonella species in food samples is routinely performed using conventional culture-based techniques, which are labor intensive, involve well-trained personnel, and are unsuitable for on-site and high-throughput analysis. To overcome these drawbacks, many research teams have developed alternative methods like biosensors, and more particularly aptasensors, were a nucleic acid is used as biorecognition element. The increasing interest in these devices is related to their high specificity, convenience, and relative rapid response. This review aims to present the advances made in these last years in the development of biosensors for the detection and the quantification of Salmonella, highlighting applications on meat from the chicken food chain.
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Affiliation(s)
- Nathalie Paniel
- Laboratoire BAE, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France.
- Unité EMaiRIT'S, Centre Technique de la Conservation des Produits Agricoles (CTCPA), Site Agroparc, 449 Avenue Clément Ader, BP21203, 84911 Avignon, France.
| | - Thierry Noguer
- Laboratoire BAE, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France.
- Laboratoire de Biodiversité et Biotechnologies Microbiennes, USR 3579, Sorbonne Universités (UPMC) Paris 6 et CNRS, Observatoire Océanologique, 66650 Banyuls-sur-Mer, France.
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14
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Yee RA, Leifels M, Scott C, Ashbolt NJ, Liu Y. Evaluating Microbial and Chemical Hazards in Commercial Struvite Recovered from Wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5378-5386. [PMID: 30964655 DOI: 10.1021/acs.est.8b03683] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Controlled struvite (NH4MgPO4·6H2O) precipitation has become a well-known process for nutrient recovery from wastewater treatment systems to alleviate the pressures of diminishing, finite rock phosphate reservoirs. Nonetheless, coprecipitation of potential microbial and chemical hazards is poorly understood. On the other hand, antimicrobial resistance (AMR) is a major global public health concern and wastewater is thought to disseminate resistance genes within bacteria. Fecal indicator bacteria (FIB) are typically used as measures of treatment quality, and with multiresistant E. coli and Enterococcus spp. rising in concern, the quantification of FIB can be used as a preliminary method to assess the risk of AMR. Focusing on struvite produced from full-scale operations, culture and qPCR methods were utilized to identify FIB, antibiotic resistance genes, and human enteric viruses in the final product. Detection of these hazards occurred in both wet and dry struvite samples indicating that there is a potential risk that needs further consideration. Chemical and biological analyses support the idea that the presence of other wastewater components can impact struvite formation through ion and microbial interference. While heavy metal concentrations met current fertilizer standards, the presence of K, Na, Ca, and Fe ions can impact struvite purity yet provide benefit for agricultural uses. Additionally, the quantified hazards detected varied among struvite samples produced from different methods and sources, thus indicating that production methods could be a large factor in the risk associated with wastewater-recovered struvite. In all, coprecipitation of metals, fecal indicator bacteria, antimicrobial resistance genes, and human enteric viruses with struvite was shown to be likely, and future engineered wastewater systems producing struvite may require additional step(s) to manage these newly identified public health risks.
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Affiliation(s)
- Rachel A Yee
- Department of Civil and Environmental Engineering , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Mats Leifels
- Centre for Water and Environmental Research (ZWU) , University Duisburg-Essen , Essen , 47057 , Germany
- School of Public Health , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Candis Scott
- School of Public Health , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Nicholas J Ashbolt
- School of Public Health , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering , University of Alberta , Edmonton , Alberta T6G 2R3 , Canada
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SAMAD ABDUL, ABBAS FERHAT, TANVEER ZUNERA, AHMAD ZAFAR, AHMAD IRSHAD, PATCHING SIMONG, NAWAZ NIGHAT, ASMAT MUHAMMADTAUSEEF, RAZIQ ABDUL, LAH ASADUL, SHEIKH IRFANSHAHZAD, NAEEM MUHAMMAD, POKRYSHKO OLENA, MUSTAFA MOHAMMADZAHID. Prevalence of Salmonella spp. in chicken meat from Quetta retail outlets and typing through multiplex PCR. ROMANIAN BIOTECHNOLOGICAL LETTERS 2019. [DOI: 10.25083/rbl/24.2/271.279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Monitoring Viable Cells of the Biological Control Agent Lactobacillus plantarum PM411 in Aerial Plant Surfaces by Means of a Strain-Specific Viability Quantitative PCR Method. Appl Environ Microbiol 2018. [PMID: 29523544 PMCID: PMC5930365 DOI: 10.1128/aem.00107-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A viability quantitative PCR (v-qPCR) assay was developed for the unambiguous detection and quantification of Lactobacillus plantarum PM411 viable cells in aerial plant surfaces. A 972-bp region of a PM411 predicted prophage with mosaic architecture enabled the identification of a PM411 strain-specific molecular marker. Three primer sets with different amplicon lengths (92, 188, and 317 bp) and one TaqMan probe were designed. All the qPCR assays showed good linearity over a 4-log range and good efficiencies but differed in sensitivity. The nucleic acid-binding dye PEMAX was used to selectively detect and enumerate viable bacteria by v-qPCR. The primer set amplifying a 188-bp DNA fragment was selected as the most suitable for v-qPCR. The performance of the method was assessed on apple blossoms, pear, strawberry, and kiwifruit leaves in potted plants under controlled environmental conditions, as well as pear and apple blossoms under field conditions, by comparing v-qPCR population estimations to those obtained by qPCR and specific plate counting on de Man-Rogosa-Sharpe (MRS)-rifampin. The population estimation did not differ significantly between methods when conditions were conducive to bacterial survival. However, under stressful conditions, differences between methods were observed due to cell death or viable-but-nonculturable state induction. While qPCR overestimated the population level, plate counting underestimated this value in comparison to v-qPCR. PM411 attained stable population levels of viable cells on the flower environment under high relative humidity. However, the unfavorable conditions on the leaf surface and the relatively dryness in the field caused an important decrease in the viable population. IMPORTANCE The v-qPCR method in combination with plate counting and qPCR is a powerful tool for studies of colonization and survival under field conditions, to improve formulations and delivery strategies of PM411, and to optimize the dose and timing of spray schedules. It is expected that PEMAX v-qPCR could also be developed for monitoring other strains on plant surfaces not only as biological control agents but also beneficial bacteria useful in the sustainable management of crop production.
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