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Barbosa A, Azevedo NF, Goeres DM, Cerqueira L. Ecology of Legionella pneumophila biofilms: The link between transcriptional activity and the biphasic cycle. Biofilm 2024; 7:100196. [PMID: 38601816 PMCID: PMC11004079 DOI: 10.1016/j.bioflm.2024.100196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/10/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024] Open
Abstract
There has been considerable discussion regarding the environmental life cycle of Legionella pneumophila and its virulence potential in natural and man-made water systems. On the other hand, the bacterium's morphogenetic mechanisms within host cells (amoeba and macrophages) have been well documented and are linked to its ability to transition from a non-virulent, replicative state to an infectious, transmissive state. Although the morphogenetic mechanisms associated with the formation and detachment of the L. pneumophila biofilm have also been described, the capacity of the bacteria to multiply extracellularly is not generally accepted. However, several studies have shown genetic pathways within the biofilm that resemble intracellular mechanisms. Understanding the functionality of L. pneumophila cells within a biofilm is fundamental for assessing the ecology and evaluating how the biofilm architecture influences L. pneumophila survival and persistence in water systems. This manuscript provides an overview of the biphasic cycle of L. pneumophila and its implications in associated intracellular mechanisms in amoeba. It also examines the molecular pathways and gene regulation involved in L. pneumophila biofilm formation and dissemination. A holistic analysis of the transcriptional activities in L. pneumophila biofilms is provided, combining the information of intracellular mechanisms in a comprehensive outline. Furthermore, this review discusses the techniques that can be used to study the morphogenetic states of the bacteria within biofilms, at the single cell and population levels.
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Affiliation(s)
- Ana Barbosa
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Nuno F. Azevedo
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Darla M. Goeres
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- The Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Laura Cerqueira
- LEPABE – Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
- ALiCE – Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
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2
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Chai Z, Liu Y, Jia S, Li F, Hu Z, Deng Y, Yue C, Tang YZ. DNA and RNA Stability of Marine Microalgae in Cold-Stored Sediments and Its Implications in Metabarcoding Analyses. Int J Mol Sci 2024; 25:1724. [PMID: 38339002 PMCID: PMC10855355 DOI: 10.3390/ijms25031724] [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: 12/15/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
The ever-increasing applications of metabarcoding analyses for environmental samples demand a well-designed assessment of the stability of DNA and RNA contained in cells that are deposited or buried in marine sediments. We thus conducted a qPCR quantification of the DNA and RNA in the vegetative cells of three microalgae entrapped in facsimile marine sediments and found that >90% of DNA and up to 99% of RNA for all microalgal species were degraded within 60 days at 4 °C. A further examination of the potential interference of the relic DNA of the vegetative cells with resting cyst detection in sediments was performed via a metabarcoding analysis in artificial marine sediments spiked with the vegetative cells of two Kareniaceae dinoflagellates and the resting cysts of another three dinoflagellates. The results demonstrated a dramatic decrease in the relative abundances of the two Kareniaceae dinoflagellates in 120 days, while those of the three resting cysts increased dramatically. Together, our results suggest that a positive detection of microalgae via metabarcoding analysis in DNA or RNA extracted from marine sediments strongly indicates the presence of intact or viable cysts or spores due to the rapid decay of relic DNA/RNA. This study provides a solid basis for the data interpretation of metabarcoding surveys, particularly in resting cyst detection.
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Affiliation(s)
- Zhaoyang Chai
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yuyang Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Siyang Jia
- Yellow Sea and East Sea Buoy Observation Station, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;
| | - Fengting Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Zhangxi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yunyan Deng
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Caixia Yue
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying-Zhong Tang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Z.C.); (Y.L.); (F.L.); (Z.H.); (Y.D.); (C.Y.)
- Laoshan Laboratory, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
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3
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Thomas MC, Waugh G, Vanwonterghem I, Webster NS, Rinke C, Fisher R, Luter HM, Negri AP. Protecting the invisible: Establishing guideline values for copper toxicity to marine microbiomes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166658. [PMID: 37659522 DOI: 10.1016/j.scitotenv.2023.166658] [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: 07/11/2023] [Revised: 08/24/2023] [Accepted: 08/26/2023] [Indexed: 09/04/2023]
Abstract
Understanding the rapid responses of marine microbiomes to environmental disturbances is paramount for supporting early assessments of harm to high-value ecosystems, such as coral reefs. Yet, management guidelines aimed at protecting aquatic life from environmental pollution remain exclusively defined for organisms at higher trophic levels. In this study, 16S rRNA gene amplicon sequencing was applied in conjunction with propidium monoazide for cell-viability assessment as a sensitive tool to determine taxon- and community-level changes in a seawater microbial community under copper (Cu) exposure. Bayesian model averaging was used to establish concentration-response relationships to evaluate the effects of copper on microbial composition, diversity, and richness for the purpose of estimating microbiome Hazard Concentration (mHCx) values. Predicted mHC5 values at which a 5 % change in microbial composition, diversity, and richness occurred were 1.05, 0.72, and 0.38 μg Cu L-1, respectively. Threshold indicator taxa analysis was applied across the copper concentrations to identify taxon-specific change points for decreasing taxa. These change points were then used to generate a Prokaryotic Sensitivity Distribution (PSD), from which mHCxdec values were derived for copper, suitable for the protection of 99, 95, 90, and 80 % of the marine microbiome. The mHC5dec guideline value of 0.61 μg Cu L-1, protective of 95 % of the marine microbial community, was lower than the equivalent Australian water quality guideline value based on eukaryotic organisms at higher trophic levels. This suggests that marine microbial communities might be more vulnerable, highlighting potential insufficiencies in their protection against copper pollution. The mHCx values proposed here provide approaches to quantitatively assess the effects of contaminants on microbial communities towards the inclusion of prokaryotes in future water quality guidelines.
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Affiliation(s)
- Marie C Thomas
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Institute of Marine Science, Townsville, QLD 4810, Australia; AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD 4811, Australia.
| | - Gretel Waugh
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Institute of Marine Science, Townsville, QLD 4810, Australia; AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD 4811, Australia
| | - Inka Vanwonterghem
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Nicole S Webster
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia; Australian Institute of Marine Science, Townsville, QLD 4810, Australia; Australian Antarctic Division, Hobart, TAS 7050, Australia
| | - Christian Rinke
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Rebecca Fisher
- Australian Institute of Marine Science Crawley, Crawley, WA, Australia
| | - Heidi M Luter
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia; AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD 4811, Australia
| | - Andrew P Negri
- Australian Institute of Marine Science, Townsville, QLD 4810, Australia; AIMS@JCU, Division of Research and Innovation, James Cook University, Townsville, QLD 4811, Australia
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Daddy Gaoh S, Kweon O, Ahn Y. Propidium Monoazide (PMAxx)-Recombinase Polymerase Amplification Exo (RPA Exo) Assay for Rapid Detection of Burkholderia cepacia Complex in Chlorhexidine Gluconate (CHX) and Benzalkonium Chloride (BZK) Solutions. Microorganisms 2023; 11:1401. [PMID: 37374904 DOI: 10.3390/microorganisms11061401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Both sterile and non-sterile pharmaceutical products, which include antiseptics, have been recalled due to Burkholderia cepacia complex (BCC) contamination. Therefore, minimizing the frequency of outbreaks may be conducive to the development of a quick and sensitive approach that can distinguish between live and dead loads of BCC. We have assessed an exo probe-based recombinase polymerase amplification (RPA) with 10 µM propidium monoazide (PMAxx) for selective detection of live/dead BCC cells in various concentrations of antiseptics (i.e., chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) solutions) after 24 h. The optimized assay conducted using a set of primer-probes targeting gbpT was performed at 40 °C for 20 min and shows a detection limit of 10 pg/µL of genomic DNA from B. cenocepacia J2315, equivalent to 104 colony-forming units (CFU/mL). The specificity of a newly designed primer and probe was 80% (20 negatives out of 25). The readings for total cells (i.e., without PMAxx) from 200 µg/mL CHX using PMAxx-RPA exo assay was 310 relative fluorescence units (RFU), compared to 129 RFU with PMAxx (i.e., live cells). Furthermore, in 50-500 µg/mL BZK-treated cells, a difference in the detection rate was observed between the PMAxx-RPA exo assay in live cells (130.4-459.3 RFU) and total cells (207.82-684.5 RFU). This study shows that the PMAxx-RPA exo assay appears to be a valid tool for the simple, rapid and presumptive detection of live BCC cells in antiseptics, thereby ensuring the quality and safety of pharmaceutical products.
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Affiliation(s)
- Soumana Daddy Gaoh
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Ohgew Kweon
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - Youngbeom Ahn
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
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Strmiskova M, Josephson JD, Toudic C, Pezacki JP. Optimized Bioorthogonal Non-canonical Amino Acid Tagging to Identify Serotype-Specific Biomarkers in Verotoxigenic Escherichia coli. ACS Infect Dis 2023; 9:856-863. [PMID: 36996368 DOI: 10.1021/acsinfecdis.2c00548] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
According to Canada's Food Report Card 2016, there are 4 million foodborne illnesses acquired each year in the nation alone. The leading causes of foodborne illness are pathogenic bacteria such as shigatoxigenic/verotoxigenic Escherichia coli (STEC/VTEC) and Listeria monocytogenes. Most current detection methods used to identify these bacterial pathogens are limited in their validity since they are not specific to detecting metabolically active organisms, potentially generating false-positive results from non-living or non-viable bacteria. Previously, our lab developed an optimized bioorthogonal non-canonical amino acid tagging (BONCAT) method which allows for the labeling of translationally active wild-type pathogenic bacteria. Incorporation of homopropargyl glycine (HPG) into the cellular surfaces of bacteria allows for protein tagging using the bioorthogonal alkyne handle to report on the presence of pathogenic bacteria. Here, we use proteomics to identify more than 400 proteins differentially detected by BONCAT between at least two of five different VTEC serotypes. These findings pave the way for future examination of these proteins as biomarkers in BONCAT-utilizing assays.
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Affiliation(s)
- Miroslava Strmiskova
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada
| | - Jason D Josephson
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada
| | - Caroline Toudic
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada
| | - John Paul Pezacki
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, University of Ottawa, 10 Marie-Curie Private, Ottawa K1N 6N5, Canada
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6
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Nisar MA, Ross KE, Brown MH, Bentham R, Best G, Whiley H. Detection and quantification of viable but non-culturable Legionella pneumophila from water samples using flow cytometry-cell sorting and quantitative PCR. Front Microbiol 2023; 14:1094877. [PMID: 36793878 PMCID: PMC9922708 DOI: 10.3389/fmicb.2023.1094877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/03/2023] [Indexed: 02/03/2023] Open
Abstract
Legionella pneumophila is a waterborne pathogen and, as the causative agent of Legionnaires' disease, a significant public health concern. Exposure to environmental stresses, and disinfection treatments, promotes the formation of resistant and potentially infectious viable but non-culturable (VBNC) Legionella. The management of engineered water systems to prevent Legionnaires' disease is hindered by the presence of VBNC Legionella that cannot be detected using the standard culture (ISO11731:2017-05) and quantitative polymerase reaction (ISO/TS12869:2019) methods. This study describes a novel method to quantify VBNC Legionella from environmental water samples using a "viability based flow cytometry-cell sorting and qPCR" (VFC + qPCR) assay. This protocol was then validated by quantifying the VBNC Legionella genomic load from hospital water samples. The VBNC cells were unable to be cultured on Buffered Charcoal Yeast Extract (BCYE) agar; however, their viability was confirmed through their ATP activity and ability to infect amoeba hosts. Subsequently, an assessment of the ISO11731:2017-05 pre-treatment procedure demonstrated that acid or heat treatment cause underestimation of alive Legionella population. Our results showed that these pre-treatment procedures induce culturable cells to enter a VBNC state. This may explain the observed insensitivity and lack of reproducibility often observed with the Legionella culture method. This study represents the first time that flow cytometry-cell sorting in conjunction with a qPCR assay has been used as a rapid and direct method to quantify VBNC Legionella from environmental sources. This will significantly improve future research evaluating Legionella risk management approaches for the control of Legionnaires' disease.
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Affiliation(s)
- Muhammad Atif Nisar
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Kirstin E. Ross
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Giles Best
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia,Flow Cytometry Facility, Flinders University, Bedford Park, SA, Australia
| | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia,*Correspondence: Harriet Whiley, ✉
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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: 0] [Impact Index Per Article: 0] [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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Vaccinomics to Design a Multiepitope Vaccine against Legionella pneumophila. BIOMED RESEARCH INTERNATIONAL 2022; 2022:4975721. [PMID: 36164443 PMCID: PMC9509222 DOI: 10.1155/2022/4975721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 11/18/2022]
Abstract
Legionella pneumophila is found in the natural aquatic environment and can resist a wide range of environmental conditions. There are around fifty species of Legionella, at least twenty-four of which are directly linked to infections in humans. L. pneumophila is the cause of Legionnaires' disease, a potentially lethal form of pneumonia. By blocking phagosome-lysosome fusion, L. pneumophila lives and proliferates inside macrophages. For this disease, there is presently no authorized multiepitope vaccine available. For the multi-epitope-based vaccine (MEBV), the best antigenic candidates were identified using immunoinformatics and subtractive proteomic techniques. Several immunoinformatics methods were utilized to predict B and T cell epitopes from vaccine candidate proteins. To construct an in silico vaccine, epitopes (07 CTL, 03 HTL, and 07 LBL) were carefully selected and docked with MHC molecules (MHC-I and MHC-II) and human TLR4 molecules. To increase the immunological response, the vaccine was combined with a 50S ribosomal adjuvant. To maximize vaccine protein expression, MEBV was cloned and reverse-translated in Escherichia coli. To prove the MEBV's efficacy, more experimental validation is required. After its development, the resulting vaccine is greatly hoped to aid in the prevention of L. pneumophila infections.
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Trinh KTL, Lee NY. Recent Methods for the Viability Assessment of Bacterial Pathogens: Advances, Challenges, and Future Perspectives. Pathogens 2022; 11:pathogens11091057. [PMID: 36145489 PMCID: PMC9500772 DOI: 10.3390/pathogens11091057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 11/28/2022] Open
Abstract
Viability assessment is a critical step in evaluating bacterial pathogens to determine infectious risks to public health. Based on three accepted viable criteria (culturability, metabolic activity, and membrane integrity), current viability assessments are categorized into three main strategies. The first strategy relies on the culturability of bacteria. The major limitation of this strategy is that it cannot detect viable but nonculturable (VBNC) bacteria. As the second strategy, based on the metabolic activity of bacteria, VBNC bacteria can be detected. However, VBNC bacteria sometimes can enter a dormant state that allows them to silence reproduction and metabolism; therefore, they cannot be detected based on culturability and metabolic activity. In order to overcome this drawback, viability assessments based on membrane integrity (third strategy) have been developed. However, these techniques generally require multiple steps, bulky machines, and laboratory technicians to conduct the tests, making them less attractive and popular applications. With significant advances in microfluidic technology, these limitations of current technologies for viability assessment can be improved. This review summarized and discussed the advances, challenges, and future perspectives of current methods for the viability assessment of bacterial pathogens.
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Affiliation(s)
- Kieu The Loan Trinh
- Department of Industrial Environmental Engineering, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Korea
| | - Nae Yoon Lee
- Department of BioNano Technology, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Korea
- Correspondence:
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Khan IUH, Murdock A, Mahmud M, Cloutier M, Benoit T, Bashar S, Patidar R, Mi R, Daneshfar B, Farenhorst A, Kumar A. Quantitative Assessment of First Nations Drinking Water Distribution Systems for Detection and Prevalence of Thermophilic Campylobacter Species. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10466. [PMID: 36078183 PMCID: PMC9518054 DOI: 10.3390/ijerph191710466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/03/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Water is considered a major route for transmitting human-associated pathogens. Although microbial water quality indicators are used to test for the presence of waterborne pathogens in drinking water, the two are poorly correlated. The current study investigates the prevalence of thermophilic DNA markers specific for Campylobacter spp. (C. jejuni and C. coli) in source water and throughout the water distribution systems of two First Nations communities in Manitoba, Canada. A total of 220 water samples were collected from various points of the drinking water distribution system (DWDS) between 2016 and 2018. Target Campylobacter spp. were always (100%) detected in a home with a fiberglass (CF) cistern, as well as the community standpipe (SP). The target bacteria were also frequently detected in treated water at the Water Treatment Plant (WTP) (78%), homes with polyethylene (CP) (60%) and concrete (CC) (58%) cisterns, homes with piped (P) water (43%) and water truck (T) samples (20%), with a maximum concentration of 1.9 × 103 cells 100 mL-1 (C. jejuni) and 5.6 × 105 cells 100 mL-1 (C. coli). Similarly, target bacteria were detected in 68% of the source water samples with a maximum concentration of 4.9 × 103 cells 100 mL-1 (C. jejuni) and 8.4 × 105 cells 100 mL-1 (C. coli). Neither target Campylobacter spp. was significantly associated with free and total chlorine concentrations in water. The study results indicate that there is an immediate need to monitor Campylobacter spp. in small communities of Canada and, particularly, to improve the DWDS in First Nations communities to minimize the risk of Campylobacter infection from drinking water sources. Further research is warranted in improving/developing processes and technologies to eliminate microbial contaminants from water.
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Affiliation(s)
- Izhar U. H. Khan
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON K1A 0C6, Canada
| | - Anita Murdock
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Maria Mahmud
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON K1A 0C6, Canada
| | - Michel Cloutier
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON K1A 0C6, Canada
| | - Thomas Benoit
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON K1A 0C6, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Sabrin Bashar
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Rakesh Patidar
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ruidong Mi
- Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Bahram Daneshfar
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON K1A 0C6, Canada
| | - Annemieke Farenhorst
- Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ayush Kumar
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Rodríguez-Herrera J, Cabado AG, Bodelón G, Cunha SC, Pinto V, Fernandes JO, Lago J, Muñoz S, Pastoriza-Santos I, Sousa P, Gonçalves L, López-Cabo M, Pérez-Juste J, Santos J, Minas G. Methodological Approaches for Monitoring Five Major Food Safety Hazards Affecting Food Production in the Galicia-Northern Portugal Euroregion. Foods 2021; 11:84. [PMID: 35010210 PMCID: PMC8750003 DOI: 10.3390/foods11010084] [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: 11/25/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
The agri-food industry has historically determined the socioeconomic characteristics of Galicia and Northern Portugal, and it was recently identified as an area for collaboration in the Euroregion. In particular, there is a need for action to help to ensure the provision of safe and healthy foods by taking advantage of key enabling technologies. The goals of the FOODSENS project are aligned with this major objective, specifically with the development of biosensors able to monitor hazards relevant to the safety of food produced in the Euroregion. The present review addresses the state of the art of analytical methodologies and techniques-whether commercially available or in various stages of development-for monitoring food hazards, such as harmful algal blooms, mycotoxins, Listeria monocytogenes, allergens, and polycyclic aromatic hydrocarbons. We discuss the pros and cons of these methodologies and techniques and address lines of research for point-of-care detection. Accordingly, the development of miniaturized automated monitoring strategies is considered a priority in terms of health and economic interest, with a significant impact in several areas, such as food safety, water quality, pollution control, and public health. Finally, we present potential market opportunities that could result from the availability of rapid and reliable commercial methodologies.
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Affiliation(s)
- Juan Rodríguez-Herrera
- Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (IIM-CSIC), 36208 Vigo, Spain; (S.M.); (M.L.-C.)
| | - Ana G. Cabado
- ANFACO-CECOPESCA, Ctra. Colexio Universitario, 16, 36310 Vigo, Spain; (A.G.C.); (J.L.)
| | - Gustavo Bodelón
- CINBIO, Campus Universitario As Lagoas, Universidade de Vigo, 36310 Vigo, Spain; (G.B.); (I.P.-S.); (J.P.-J.)
- Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36310 Vigo, Spain
| | - Sara C. Cunha
- LAQV-REQUIMTE, Laboratory of Bromatology and Hidrology, Department of Chemical Sciences, Facultaty of Pharmacy, University of Porto, Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; (S.C.C.); (J.O.F.); (J.S.)
| | - Vânia Pinto
- Center for MicroElectromechanical Systems (CMEMS-UMinho), University of Minho, 4800-058 Guimarães, Portugal; (V.P.); (P.S.); (L.G.); (G.M.)
| | - José O. Fernandes
- LAQV-REQUIMTE, Laboratory of Bromatology and Hidrology, Department of Chemical Sciences, Facultaty of Pharmacy, University of Porto, Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; (S.C.C.); (J.O.F.); (J.S.)
| | - Jorge Lago
- ANFACO-CECOPESCA, Ctra. Colexio Universitario, 16, 36310 Vigo, Spain; (A.G.C.); (J.L.)
| | - Silvia Muñoz
- Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (IIM-CSIC), 36208 Vigo, Spain; (S.M.); (M.L.-C.)
| | - Isabel Pastoriza-Santos
- CINBIO, Campus Universitario As Lagoas, Universidade de Vigo, 36310 Vigo, Spain; (G.B.); (I.P.-S.); (J.P.-J.)
- Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36310 Vigo, Spain
| | - Paulo Sousa
- Center for MicroElectromechanical Systems (CMEMS-UMinho), University of Minho, 4800-058 Guimarães, Portugal; (V.P.); (P.S.); (L.G.); (G.M.)
| | - Luís Gonçalves
- Center for MicroElectromechanical Systems (CMEMS-UMinho), University of Minho, 4800-058 Guimarães, Portugal; (V.P.); (P.S.); (L.G.); (G.M.)
| | - Marta López-Cabo
- Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (IIM-CSIC), 36208 Vigo, Spain; (S.M.); (M.L.-C.)
| | - Jorge Pérez-Juste
- CINBIO, Campus Universitario As Lagoas, Universidade de Vigo, 36310 Vigo, Spain; (G.B.); (I.P.-S.); (J.P.-J.)
- Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36310 Vigo, Spain
| | - João Santos
- LAQV-REQUIMTE, Laboratory of Bromatology and Hidrology, Department of Chemical Sciences, Facultaty of Pharmacy, University of Porto, Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; (S.C.C.); (J.O.F.); (J.S.)
| | - Graça Minas
- Center for MicroElectromechanical Systems (CMEMS-UMinho), University of Minho, 4800-058 Guimarães, Portugal; (V.P.); (P.S.); (L.G.); (G.M.)
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12
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Zhang C, Lu J. Legionella: A Promising Supplementary Indicator of Microbial Drinking Water Quality in Municipal Engineered Water Systems. FRONTIERS IN ENVIRONMENTAL SCIENCE 2021; 9:1-22. [PMID: 35004706 PMCID: PMC8740890 DOI: 10.3389/fenvs.2021.684319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Opportunistic pathogens (OPs) are natural inhabitants and the predominant disease causative biotic agents in municipal engineered water systems (EWSs). In EWSs, OPs occur at high frequencies and concentrations, cause drinking-water-related disease outbreaks, and are a major factor threatening public health. Therefore, the prevalence of OPs in EWSs represents microbial drinking water quality. Closely or routinely monitoring the dynamics of OPs in municipal EWSs is thus critical to ensuring drinking water quality and protecting public health. Monitoring the dynamics of conventional (fecal) indicators (e.g., total coliforms, fecal coliforms, and Escherichia coli) is the customary or even exclusive means of assessing microbial drinking water quality. However, those indicators infer only fecal contamination due to treatment (e.g., disinfection within water utilities) failure and EWS infrastructure issues (e.g., water main breaks and infiltration), whereas OPs are not contaminants in drinking water. In addition, those indicators appear in EWSs at low concentrations (often absent in well-maintained EWSs) and are uncorrelated with OPs. For instance, conventional indicators decay, while OPs regrow with increasing hydraulic residence time. As a result, conventional indicators are poor indicators of OPs (the major aspect of microbial drinking water quality) in EWSs. An additional or supplementary indicator that can well infer the prevalence of OPs in EWSs is highly needed. This systematic review argues that Legionella as a dominant OP-containing genus and natural inhabitant in EWSs is a promising candidate for such a supplementary indicator. Through comprehensively comparing the behavior (i.e., occurrence, growth and regrowth, spatiotemporal variations in concentrations, resistance to disinfectant residuals, and responses to physicochemical water quality parameters) of major OPs (e.g., Legionella especially L. pneumophila, Mycobacterium, and Pseudomonas especially P. aeruginosa), this review proves that Legionella is a promising supplementary indicator for the prevalence of OPs in EWSs while other OPs lack this indication feature. Legionella as a dominant natural inhabitant in EWSs occurs frequently, has a high concentration, and correlates with more microbial and physicochemical water quality parameters than other common OPs. Legionella and OPs in EWSs share multiple key features such as high disinfectant resistance, biofilm formation, proliferation within amoebae, and significant spatiotemporal variations in concentrations. Therefore, the presence and concentration of Legionella well indicate the presence and concentrations of OPs (especially L. pneumophila) and microbial drinking water quality in EWSs. In addition, Legionella concentration indicates the efficacies of disinfectant residuals in EWSs. Furthermore, with the development of modern Legionella quantification methods (especially quantitative polymerase chain reactions), monitoring Legionella in ESWs is becoming easier, more affordable, and less labor-intensive. Those features make Legionella a proper supplementary indicator for microbial drinking water quality (especially the prevalence of OPs) in EWSs. Water authorities may use Legionella and conventional indicators in combination to more comprehensively assess microbial drinking water quality in municipal EWSs. Future work should further explore the indication role of Legionella in EWSs and propose drinking water Legionella concentration limits that indicate serious public health effects and require enhanced treatment (e.g., booster disinfection).
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, OH, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
- Correspondence: Jingrang Lu,
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13
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Bell TH, Bell T. Many roads to bacterial generalism. FEMS Microbiol Ecol 2021; 97:6006266. [PMID: 33238305 DOI: 10.1093/femsec/fiaa240] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
The fundamental niches of bacteria can be defined along many environmental axes, including temperature tolerance and resources consumed, while interactions with other organisms can constrain (e.g. competition) or enlarge (e.g. cross-feeding) realized niches. Organisms are often categorized as generalists or specialists, corresponding to broad or narrow niche requirements, which can then be linked to their functional role in an ecosystem. We show how these terms are applied to bacteria, make predictions about how the type and extent of generalism displayed by an organism relates to its functional potential and discuss the value of collecting different types of generalist bacteria. We believe that new approaches that take advantage of both high-throughput sequencing and environmental manipulation can allow us to understand the many types of generalism found within both cultivated and yet-to-be-cultivated bacteria.
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Affiliation(s)
- Terrence H Bell
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, 16802, USA.,Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Thomas Bell
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
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14
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Garner E, Davis BC, Milligan E, Blair MF, Keenum I, Maile-Moskowitz A, Pan J, Gnegy M, Liguori K, Gupta S, Prussin AJ, Marr LC, Heath LS, Vikesland PJ, Zhang L, Pruden A. Next generation sequencing approaches to evaluate water and wastewater quality. WATER RESEARCH 2021; 194:116907. [PMID: 33610927 DOI: 10.1016/j.watres.2021.116907] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/15/2021] [Accepted: 02/03/2021] [Indexed: 05/24/2023]
Abstract
The emergence of next generation sequencing (NGS) is revolutionizing the potential to address complex microbiological challenges in the water industry. NGS technologies can provide holistic insight into microbial communities and their functional capacities in water and wastewater systems, thus eliminating the need to develop a new assay for each target organism or gene. However, several barriers have hampered wide-scale adoption of NGS by the water industry, including cost, need for specialized expertise and equipment, challenges with data analysis and interpretation, lack of standardized methods, and the rapid pace of development of new technologies. In this critical review, we provide an overview of the current state of the science of NGS technologies as they apply to water, wastewater, and recycled water. In addition, a systematic literature review was conducted in which we identified over 600 peer-reviewed journal articles on this topic and summarized their contributions to six key areas relevant to the water and wastewater fields: taxonomic classification and pathogen detection, functional and catabolic gene characterization, antimicrobial resistance (AMR) profiling, bacterial toxicity characterization, Cyanobacteria and harmful algal bloom identification, and virus characterization. For each application, we have presented key trends, noteworthy advancements, and proposed future directions. Finally, key needs to advance NGS technologies for broader application in water and wastewater fields are assessed.
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Affiliation(s)
- Emily Garner
- Wadsworth Department of Civil and Environmental Engineering, West Virginia University, 1306 Evansdale Drive, Morgantown, WV 26505, United States.
| | - Benjamin C Davis
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Erin Milligan
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Matthew Forrest Blair
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Ishi Keenum
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Ayella Maile-Moskowitz
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Jin Pan
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Mariah Gnegy
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Krista Liguori
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Suraj Gupta
- The Interdisciplinary PhD Program in Genetics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, VA 24061, United States
| | - Aaron J Prussin
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Linsey C Marr
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Lenwood S Heath
- Department of Computer Science, Virginia Tech, 225 Stranger Street, Blacksburg, VA 24061, United States
| | - Peter J Vikesland
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States
| | - Liqing Zhang
- Department of Computer Science, Virginia Tech, 225 Stranger Street, Blacksburg, VA 24061, United States
| | - Amy Pruden
- Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry Street, Blacksburg, VA 24061, United States.
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15
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Eble D, Gehrig V, Schubert-Ullrich P, Köppel R, Füchslin HP. Comparison of the culture method with multiplex PCR for the confirmation of Legionella spp. and Legionella pneumophila. J Appl Microbiol 2021; 131:2600-2609. [PMID: 33847421 PMCID: PMC9292777 DOI: 10.1111/jam.15103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/04/2021] [Accepted: 04/09/2021] [Indexed: 11/30/2022]
Abstract
AIMS The detection and enumeration of Legionella spp. in water samples are typically performed via a cultural technique standardized in ISO 11731. This method is time-consuming (up to 15 days), and the specificity of the confirmation step is questionable. This study proposes the use of multiplex polymerase chain reaction (PCR) to confirm presumptive Legionella colonies directly from the culture plate; this shortens the response time by 2-5 days while still reporting results in colony forming units (CFU). METHODS AND RESULTS Two laboratories analysed a total of 290 colonies to compare the confirmation step of Legionella spp. and Legionella pneumophila in accordance with ISO 11731 by culture growth and agglutination vs multiplex PCR. Discordant results were resolved by the swiss national reference laboratory. The data were evaluated following ISO 16140 and showed that the PCR-technique had higher specificity. CONCLUSIONS The confirmation of Legionella spp., L. pneumophila and L. pneumophila serogroup 1 by multiplex PCR allows detection of positive colonies more rapidly and with higher specificity. SIGNIFICANCE AND IMPACT OF THE STUDY The study highlights a possibility to shorten the response time significantly during the enumeration of Legionella spp. and achieving a higher specificity while adhering to the legally recognized reporting in CFU.
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Affiliation(s)
- D Eble
- Industrielle Werke Basel, Basel, Switzerland
| | - V Gehrig
- Kantonales Labor Zürich, Zürich, Switzerland
| | | | - R Köppel
- Kantonales Labor Zürich, Zürich, Switzerland
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16
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Tut G, Magan N, Brain P, Xu X. Molecular Assay Development to Monitor the Kinetics of Viable Populations of Two Biocontrol Agents, Bacillus subtilis QST 713 and Gliocladium catenulatum J1446, in the Phyllosphere of Lettuce Leaves. BIOLOGY 2021; 10:biology10030224. [PMID: 33804029 PMCID: PMC8001495 DOI: 10.3390/biology10030224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 11/19/2022]
Abstract
Simple Summary There is a need to be able to track the viable populations of biocontrol agents when applied on the foliar surfaces of plants. We have developed a molecular-based method for the quantification of viable cells of two commercial biocontrol agents—a bacterium (Bacillus subtilis) and a fungus (Gliocladium catenulatum). The method has been tested on the leaf surfaces of lettuce plants to examine the changes in viable population over 10–12 days for the first time. Abstract Optimising the use of biocontrol agents (BCAs) requires the temporal tracking of viable populations in the crop phyllosphere to ensure that effective control can be achieved. No sensitive systems for quantifying viable populations of commercially available BCAs, such as Bacillus subtilis and Gliocladium catenulatum, in the phyllosphere of crop plants are available. The objective of this study was to develop a method to quantify viable populations of these two BCAs in the crop phyllosphere. A molecular tool based on propidium monoazide (PMA) (PMAxx™-qPCR) capable of quantifying viable populations of these two BCAs was developed. Samples were treated with PMAxx™ (12.5–100 μM), followed by 15 min incubation, exposure to a 800 W halogen light for 30 min, DNA extraction, and quantification using qPCR. This provided a platform for using the PMAxx™-qPCR technique for both BCAs to differentiate viable from dead cells. The maximum number of dead cells blocked, based on the DNA, was 3.44 log10 for B. subtilis and 5.75 log10 for G. catenulatum. Validation studies showed that this allowed accurate quantification of viable cells. This method provided effective quantification of the temporal changes in viable populations of the BCAs in commercial formulations on lettuce leaves in polytunnel and glasshouse production systems.
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Affiliation(s)
- Gurkan Tut
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK
| | - Naresh Magan
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK
- Correspondence:
| | - Philip Brain
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
| | - Xiangming Xu
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
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17
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Khan IUH, Becker A, Cloutier M, Plötz M, Lapen DR, Wilkes G, Topp E, Abdulmawjood A. Loop-mediated isothermal amplification: Development, validation and application of simple and rapid assays for quantitative detection of species of Arcobacteraceae family- and species-specific Aliarcobacter faecis and Aliarcobacter lanthieri. J Appl Microbiol 2020; 131:288-299. [PMID: 33174331 PMCID: PMC8359143 DOI: 10.1111/jam.14926] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/29/2022]
Abstract
Aim The family Arcobacteraceae formerly genus Arcobacter has recently been reclassified into six genera. Among nine species of the genus Aliarcobacter, Aliarcobacter faecis and Aliarcobacter lanthieri have been identified as emerging pathogens potentially cause health risks to humans and animals. This study was designed to develop/optimize, validate and apply Arcobacteraceae family‐ and two species‐specific (A. faecis and A. lanthieri) loop‐mediated isothermal amplification (LAMP) assays to rapidly detect and quantify total number of cells in various environmental niches. Methods and Results Three sets of LAMP primers were designed from conserved and variable regions of 16S rRNA (family‐specific) and gyrB (species‐specific) genes. Optimized Arcobacteraceae family‐specific LAMP assay correctly amplified and detected 24 species, whereas species‐specific LAMP assays detected A. faecis and A. lanthieri reference strains as well as 91 pure and mixed culture isolates recovered from aquatic and faecal sources. The specificity of LAMP amplification of A. faecis and A. lanthieri was further confirmed by restriction fragment length polymorphism analysis. Assay sensitivities were tested using variable DNA concentrations extracted from simulated target species cells in an autoclaved agricultural water sample by achieving a minimum detection limit of 10 cells mL−1 (10 fg). Direct DNA‐based quantitative detection, from agricultural surface water, identified A. faecis (17%) and A. lanthieri (1%) at a low frequency compared to family‐level (93%) with the concentration ranging from 2·1 × 101 to 2·2 × 105 cells 100 mL−1. Conclusions Overall, these three DNA‐based rapid and cost‐effective novel LAMP assays are sensitive and can be completed in less than 40 min. They have potential for on‐site quantitative detection of species of family Arcobacteraceae, A. faecis and A. lanthieri in food, environmental and clinical matrices. Significance and Impact of the Study The newly developed LAMP assays are specific, sensitive, accurate with higher reproducibility that have potential to facilitate in a less equipped lab setting and can help in early quantitative detection and rate of prevalence in environmental niches. The assays can be adopted in the diagnostic labs and epidemiological studies.
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Affiliation(s)
- I U H Khan
- Ottawa Research and Development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - A Becker
- Institute of Food Quality and Food Safety, Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Foundation, Hannover, Germany
| | - M Cloutier
- Ottawa Research and Development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - M Plötz
- Institute of Food Quality and Food Safety, Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Foundation, Hannover, Germany
| | - D R Lapen
- Ottawa Research and Development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, ON, Canada
| | - G Wilkes
- Ottawa Research and Development Centre (ORDC), Agriculture and Agri-Food Canada, Ottawa, ON, Canada.,Natural Resources Canada, Ottawa, ON, Canada
| | - E Topp
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, Canada
| | - A Abdulmawjood
- Institute of Food Quality and Food Safety, Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Foundation, Hannover, Germany
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18
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A Species-Specific qPCR Method for Enumeration of Lactobacillus sanfranciscensis, Lactobacillus brevis, and Lactobacillus curvatus During Cocultivation in Sourdough. FOOD ANAL METHOD 2020. [DOI: 10.1007/s12161-020-01920-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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19
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Nocker A, Schulte-Illingheim L, Frösler J, Welp L, Sperber O, Hugo A. Microbiological examination of water and aerosols from four industrial evaporative cooling systems in regard to risk of Legionella emissions and methodological suggestions for surveillance. Int J Hyg Environ Health 2020; 229:113591. [DOI: 10.1016/j.ijheh.2020.113591] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/22/2022]
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20
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Deepnarain N, Nasr M, Amoah ID, Enitan-Folami AM, Reddy P, Stenström TA, Kumari S, Bux F. Impact of sludge bulking on receiving environment using quantitative microbial risk assessment (QMRA)-based management for full-scale wastewater treatment plants. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 267:110660. [PMID: 32421681 DOI: 10.1016/j.jenvman.2020.110660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/16/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
During sludge bulking in wastewater treatment plants (WWTPs), high amounts of potentially pathogenic bacteria would release into the environment, causing various human-health risks. This is the first study attempting to assess the microbial infections associated with the reuse of WWTP effluents under various bulking conditions. Three common waterborne pathogens, viz., E. coli O157:H7, Salmonella, and Mycobacterium, were quantified from full-scale WWTPs using DNA extraction and qPCR at different sludge volume indices (SVIs). The detected pathogens were incorporated into a quantitative microbial risk assessment (QMRA) model to determine the applicability of WWTP discharge for recreational (bathing) activities and agricultural practices. The QMRA exposures were children, women, and men during swimming, and farmers and vegetable consumers during irrigation. Bacterial abundance in the treated wastewater increased in response to SVIs, and the QMRA values at all bulking events exceeded the tolerable risk of one case of infection per 10,000 people per year. Hence, various disinfection scenarios (chlorination, ultraviolet, and ozonation) were hypothetically tested to control the risks associated with pathogenic bacteria, allowing for safe disposal and reuse of the treated effluent. The ultraviolet application provided the highest ability to inactivate the pathogenic bacteria, except for the case of children exposed to Salmonella infection during swimming. The reduction of Mycobacterium infection risks with either chlorination or ozonation showed inefficient results. This study would be helpful for the management of human health risks associated with effluent wastewater containing pathogens, i.e., particularly concerning the case of sludge bulking.
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Affiliation(s)
- Nashia Deepnarain
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4000, South Africa
| | - Mahmoud Nasr
- Sanitary Engineering Department, Faculty of Engineering, Alexandria University, Alexandria, 21544, Egypt
| | - Isaac Dennis Amoah
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4000, South Africa
| | | | - Poovendhree Reddy
- Department of Community Health Studies, Faculty of Health Sciences, Durban University of Technology, South Africa
| | - Thor Axel Stenström
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4000, South Africa
| | - Sheena Kumari
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4000, South Africa
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4000, South Africa.
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21
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Saad M, Chinerman D, Tabrizian M, Faucher SP. Identification of two aptamers binding to Legionella pneumophila with high affinity and specificity. Sci Rep 2020; 10:9145. [PMID: 32499557 PMCID: PMC7272621 DOI: 10.1038/s41598-020-65973-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 05/13/2020] [Indexed: 12/21/2022] Open
Abstract
Legionella pneumophila (Lp) is a water borne bacterium causing Legionnaires’ Disease (LD) in humans. Rapid detection of Lp in water system is essential to reduce the risk of LD outbreaks. The methods currently available require expert skills and are time intensive, thus delaying intervention. In situ detection of Lp by biosensor would allow rapid implementation of control strategies. To this end, a biorecognition element is required. Aptamers are considered promising biorecognition molecules for biosensing. Aptamers are short oligonucleotide sequence folding into a specific structure and are able to bind to specific molecules. Currently, no aptamer and thus no aptamer-based technology exists for the detection of Lp. In this study, Systemic Evolution of Ligands through EXponential enrichment (SELEX) was used to identify aptamers binding specifically to Lp. Ten rounds of positive selection and two rounds of counter-selection against two Pseudomonas species were performed. Two aptamers binding strongly to Lp were identified with KD of 116 and 135 nM. Binding specificity of these two aptamers to Lp was confirmed by flow cytometry and fluorescence microscopy. Therefore, these two aptamers are promising biorecognition molecules for the detection of Lp in water systems.
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Affiliation(s)
- Mariam Saad
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.,Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, J2S 2M2, Canada
| | - Deanna Chinerman
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Maryam Tabrizian
- Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, H3A 2B4, Canada.,Faculty of Dentistry, McGill University, Montreal, Quebec, H3A 2B4, Canada
| | - Sebastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada. .,Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, J2S 2M2, Canada.
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22
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Ramkissoon S, MacArthur I, Ibrahim M, de Graaf H, Read RC, Preston A. A qPCR assay for Bordetella pertussis cells that enumerates both live and dead bacteria. PLoS One 2020; 15:e0232334. [PMID: 32353041 PMCID: PMC7192480 DOI: 10.1371/journal.pone.0232334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/13/2020] [Indexed: 02/03/2023] Open
Abstract
Bordetella pertussis is the causative agent of whooping cough, commonly referred to as pertussis. Although the incidence of pertussis was reduced through vaccination, during the last thirty years it has returned to high levels in a number of countries. This resurgence has been linked to the switch from the use of whole-cell to acellular vaccines. Protection afforded by acellular vaccines appears to be short-lived compared to that afforded by whole cell vaccines. In order to inform future vaccine improvement by identifying immune correlates of protection, a human challenge model of B. pertussis colonisation has been developed. Accurate measurement of colonisation status in this model has required development of a qPCR-based assay to enumerate B. pertussis in samples that distinguishes between viable and dead bacteria. Here we report the development of this assay and its performance in the quantification of B. pertussis from human challenge model samples. This assay has future utility in diagnostic labs and in research where a quantitative measure of both B. pertussis number and viability is required.
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Affiliation(s)
- Stacy Ramkissoon
- Milner Centre for Evolution, University of Bath, Bath, United Kingdom
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Iain MacArthur
- Milner Centre for Evolution, University of Bath, Bath, United Kingdom
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Muktar Ibrahim
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- School of Clinical Experimental Sciences, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
| | - Hans de Graaf
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- School of Clinical Experimental Sciences, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
| | - Robert C. Read
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
- School of Clinical Experimental Sciences, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
| | - Andrew Preston
- Milner Centre for Evolution, University of Bath, Bath, United Kingdom
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
- * E-mail:
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23
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Askar M, Sajid M, Nassif Y, Ashraf W, Scammell B, Bayston R. Propidium monoazide-polymerase chain reaction for detection of residual periprosthetic joint infection in two-stage revision. Mol Biol Rep 2019; 46:6463-6470. [PMID: 31587184 DOI: 10.1007/s11033-019-05092-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/22/2019] [Indexed: 12/18/2022]
Abstract
False negative culture results in periprosthetic joint infection (PJI) are not uncommon particularly when patients have received long term antibiotics. Polymerase chain reaction (PCR) has a lower specificity partly due to detection of residual DNA from dead bacteria. Propidium monoazide (PMA) prevents DNA from dead bacteria from being amplified during the PCR. This study aimed to determine the role of PMA in PCR for diagnosis of PJI. Clinical samples were tested by PCR with and without prior treatment with PMA and compared to conventional microbiological culture. The PCR assay included genus-specific primers for staphylococci and enterococci and species-specific primers for Cutibacterium acnes. The validated conditions of PMA treatment used in this study were 20 μM concentration and 5 and 10 min of dark incubation and photo-activation respectively. 202 periprosthetic tissues and explanted prostheses from 60 episodes in 58 patients undergoing revision arthroplasties for either PJI or non-infective causes were tested, by culture, PCR, and PMA-PCR. 14 of the 60 episodes satisfied the Musculoskeletal Infection Society (MSIS) criteria for PJI and 46 did not. Sensitivity of culture, PCR, and PMA-PCR were 50%, 71%, and 79% respectively. Specificities were 98%, 72%, and 89% respectively. All figures were calculated for episodes rather than samples. PMA-PCR enhanced both the specificity and the sensitivity of PCR. It has the potential to detect residual bacterial viability prior to reimplantation in the two-stage revision for PJI.
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Affiliation(s)
- Mohamed Askar
- Department of Academic Orthopaedics, Queen's Medical Centre, University of Nottingham, C Floor, West Block, Derby Road, Nottingham, NG7 2UH, UK
| | - Mariam Sajid
- Department of Academic Orthopaedics, Queen's Medical Centre, University of Nottingham, C Floor, West Block, Derby Road, Nottingham, NG7 2UH, UK
| | - Yassar Nassif
- Trauma and Orthopaedic Department, University of Nottingham Hospitals, Nottingham, UK
| | - Waheed Ashraf
- Department of Academic Orthopaedics, Queen's Medical Centre, University of Nottingham, C Floor, West Block, Derby Road, Nottingham, NG7 2UH, UK
| | - Brigitte Scammell
- Department of Academic Orthopaedics, Queen's Medical Centre, University of Nottingham, C Floor, West Block, Derby Road, Nottingham, NG7 2UH, UK
- Trauma and Orthopaedic Department, University of Nottingham Hospitals, Nottingham, UK
| | - Roger Bayston
- Department of Academic Orthopaedics, Queen's Medical Centre, University of Nottingham, C Floor, West Block, Derby Road, Nottingham, NG7 2UH, UK.
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24
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Cattò C, Cappitelli F. Testing Anti-Biofilm Polymeric Surfaces: Where to Start? Int J Mol Sci 2019; 20:E3794. [PMID: 31382580 PMCID: PMC6696330 DOI: 10.3390/ijms20153794] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.
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Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
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25
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Kumar SS, Ghosh AR. Assessment of bacterial viability: a comprehensive review on recent advances and challenges. Microbiology (Reading) 2019; 165:593-610. [DOI: 10.1099/mic.0.000786] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Shravanthi S. Kumar
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Asit Ranjan Ghosh
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
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26
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Zhai L, Li J, Tao T, Lu Z, Lv F, Bie X. Propidium monoazide real-time PCR amplification for viable Salmonella species and Salmonella Heidelberg in pork. Can J Microbiol 2019; 65:477-485. [PMID: 30865841 DOI: 10.1139/cjm-2018-0547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Salmonella enterica serovar Heidelberg causes foodborne infections and is a major threat to the food chain and public health. In this study, we aimed to develop a rapid molecular typing approach to identify Salmonella enterica serovar Heidelberg. Using comparative genomics, four serovar-specific gene fragments were identified, and a real-time polymerase chain reaction (PCR) combined with a propidium monoazide (PMA) pretreatment method was developed for simultaneous detection of viable Salmonella sp. (invA) and Salmonella Heidelberg (SeHA_C3258). The assay showed 100% specificity for all strains tested. The assay was able to distinguish effectively viable or dead cells with the PMA. The detection limit was 2.4 CFU/mL following 6 h of incubation in enrichment Luria-Bertani medium, and the assay could detect 1.7 × 102 CFU/mL in the presence of pork background flora. In artificially contaminated pork, real-time PCR detected inoculum levels of 1.15 CFU/25 g of pork after a 6 h enrichment. Thus, our findings indicated that this comparative genomics approach could be used to screen for serovar-specific fragments and that real-time PCR with PMA was a simple and reliable method for detecting viability of Salmonella species and Salmonella Heidelberg.
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Affiliation(s)
- Ligong Zhai
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China.,b College of Food Engineering, Anhui Science and Technology University Chuzhou, Anhui Province, China
| | - Junjie Li
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Tingting Tao
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Zhaoxin Lu
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Fengxia Lv
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
| | - Xiaomei Bie
- a College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control, Ministry of Agriculture of China, Nanjing, Jiangsu Province, China
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27
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Mangiaterra G, Amiri M, Di Cesare A, Pasquaroli S, Manso E, Cirilli N, Citterio B, Vignaroli C, Biavasco F. Detection of viable but non-culturable Pseudomonas aeruginosa in cystic fibrosis by qPCR: a validation study. BMC Infect Dis 2018; 18:701. [PMID: 30587160 PMCID: PMC6307279 DOI: 10.1186/s12879-018-3612-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/10/2018] [Indexed: 12/29/2022] Open
Abstract
Background Routine culture-based diagnosis of Pseudomonas aeruginosa lung infection in Cystic Fibrosis (CF) patients can be hampered by the phenotypic variability of the microorganism, including its transition to a Viable But Non-Culturable (VBNC) state. The aim of this study was to validate an ecfX-targeting qPCR protocol developed to detect all viable P. aeruginosa bacteria and to identify VBNC forms in CF sputum samples. Methods The study involved 115 P. aeruginosa strains of different origins and 10 non-P. aeruginosa strains and 88 CF sputum samples, 41 Culture-Positive (CP) and 47 Culture-Negative (CN). Spiking assays were performed using scalar dilutions of a mixture of live and dead P. aeruginosa ATCC 9027 and a pooled P. aeruginosa-free sputum batch. Total DNA from sputum samples was extracted by a commercial kit, whereas a crude extract was obtained from the broth cultures. Extracellular DNA (eDNA) interference was evaluated by comparing the qPCR counts obtained from DNase-treated and untreated aliquots of the same samples. The statistical significance of the results was assessed by the Wilcoxon test and Student’s t test. Results The newly-developed qPCR protocol identified 96.6% of the P. aeruginosa isolates; no amplification was obtained with strains belonging to different species. Spiking assays supported protocol reliability, since counts always matched the amount of live bacteria, thus excluding the interference of dead cells and eDNA. The protocol sensitivity threshold was 70 cells/ml of the original sample. Moreover, qPCR detected P. aeruginosa in 9/47 CN samples and showed higher bacterial counts compared with the culture method in 10/41 CP samples. Conclusions Our findings demonstrate the reliability of the newly-developed qPCR protocol and further highlight the need for harnessing a non-culture approach to achieve an accurate microbiological diagnosis of P. aeruginosa CF lung infection and a greater understanding of its evolution. Electronic supplementary material The online version of this article (10.1186/s12879-018-3612-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gianmarco Mangiaterra
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy.
| | - Mehdi Amiri
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Andrea Di Cesare
- Department of Earth, Environmental and Life Sciences, University of Genoa, Corso Europa, 26, 16132, Genoa, Italy
| | - Sonia Pasquaroli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Esther Manso
- Microbiology Laboratory, Azienda Ospedaliero-Universitaria, Ospedali Riuniti Umberto I°- G.M. Lancisi - G. Salesi, Ancona, Italy
| | - Natalia Cirilli
- Mother-Child Department, Cystic Fibrosis Referral Care Center, United Hospitals, Ancona, Italy
| | - Barbara Citterio
- Department of Biomolecular Sciences sect. Biotechnology, University of Urbino "Carlo Bo", Urbino, Italy
| | - Carla Vignaroli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Francesca Biavasco
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
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28
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Kiely CJ, Pavli P, O'Brien CL. The microbiome of translocated bacterial populations in patients with and without inflammatory bowel disease. Intern Med J 2018; 48:1346-1354. [DOI: 10.1111/imj.13998] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/20/2018] [Accepted: 06/07/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Christopher J. Kiely
- IBD Research Laboratory, Medical School, College of Medicine, Biology and EnvironmentAustralian National University Canberra Capital of Australia Australia
| | - Paul Pavli
- IBD Research Laboratory, Medical School, College of Medicine, Biology and EnvironmentAustralian National University Canberra Capital of Australia Australia
- Gastroenterology and Hepatology UnitCanberra Hospital Canberra Australian Capital Territory Australia
| | - Claire L. O'Brien
- IBD Research Laboratory, Medical School, College of Medicine, Biology and EnvironmentAustralian National University Canberra Capital of Australia Australia
- Gastroenterology and Hepatology UnitCanberra Hospital Canberra Australian Capital Territory Australia
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29
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Role of food sanitising treatments in inducing the ‘viable but nonculturable’ state of microorganisms. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.04.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Boss R, Baumgartner A, Kroos S, Blattner M, Fretz R, Moor D. Rapid detection of viableLegionella pneumophilain tap water by a qPCR and RT-PCR-based method. J Appl Microbiol 2018; 125:1216-1225. [DOI: 10.1111/jam.13932] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 12/22/2022]
Affiliation(s)
- R. Boss
- Federal Food Safety and Veterinary Office; Berne Switzerland
| | - A. Baumgartner
- Federal Food Safety and Veterinary Office; Berne Switzerland
| | - S. Kroos
- Food Safety and Veterinary Office; Canton of Basel-Landschaft; Liestal Switzerland
| | - M. Blattner
- Food Safety and Veterinary Office; Canton of Basel-Landschaft; Liestal Switzerland
| | - R. Fretz
- Food Safety and Veterinary Office; Canton of Basel-Landschaft; Liestal Switzerland
| | - D. Moor
- Federal Food Safety and Veterinary Office; Berne Switzerland
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31
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Hamilton KA, Hamilton MT, Johnson W, Jjemba P, Bukhari Z, LeChevallier M, Haas CN. Health risks from exposure to Legionella in reclaimed water aerosols: Toilet flushing, spray irrigation, and cooling towers. WATER RESEARCH 2018; 134:261-279. [PMID: 29428779 DOI: 10.1016/j.watres.2017.12.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 05/05/2023]
Abstract
The use of reclaimed water brings new challenges for the water industry in terms of maintaining water quality while increasing sustainability. Increased attention has been devoted to opportunistic pathogens, especially Legionella pneumophila, due to its growing importance as a portion of the waterborne disease burden in the United States. Infection occurs when a person inhales a mist containing Legionella bacteria. The top three uses for reclaimed water (cooling towers, spray irrigation, and toilet flushing) that generate aerosols were evaluated for Legionella health risks in reclaimed water using quantitative microbial risk assessment (QMRA). Risks are compared using data from nineteen United States reclaimed water utilities measured with culture-based methods, quantitative PCR (qPCR), and ethidium-monoazide-qPCR. Median toilet flushing annual infection risks exceeded 10-4 considering multiple toilet types, while median clinical severity infection risks did not exceed this value. Sprinkler and cooling tower risks varied depending on meteorological conditions and operational characteristics such as drift eliminator performance. However, the greatest differences between risk scenarios were due to 1) the dose response model used (infection or clinical severity infection) 2) population at risk considered (residential or occupational) and 3) differences in laboratory analytical method. Theoretical setback distances necessary to achieve a median annual infection risk level of 10-4 are proposed for spray irrigation and cooling towers. In both cooling tower and sprinkler cases, Legionella infection risks were non-trivial at potentially large setback distances, and indicate other simultaneous management practices could be needed to manage risks. The sensitivity analysis indicated that the most influential factors for variability in risks were the concentration of Legionella and aerosol partitioning and/or efficiency across all models, highlighting the importance of strategies to manage Legionella occurrence in reclaimed water.
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Affiliation(s)
- Kerry A Hamilton
- Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | | | - William Johnson
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Patrick Jjemba
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Zia Bukhari
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Mark LeChevallier
- American Water Research Laboratory, 213 Carriage Lane, Delran, New Jersey 08075, USA
| | - Charles N Haas
- Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
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32
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Nurliyana MR, Sahdan M, Wibowo K, Muslihati A, Saim H, Ahmad S, Sari Y, Mansor Z. The Detection Method ofEscherichia coliin Water Resources: A Review. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1742-6596/995/1/012065] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Lizana X, López A, Benito S, Agustí G, Ríos M, Piqué N, Marqués A, Codony F. Viability qPCR, a new tool for Legionella risk management. Int J Hyg Environ Health 2017; 220:1318-1324. [DOI: 10.1016/j.ijheh.2017.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 10/18/2022]
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34
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Pega J, Rizzo S, Rossetti L, Pérez C, Díaz G, Descalzo A, Nanni M. Impact of extracellular nucleic acids from lactic acid bacteria on qPCR and RT-qPCR results in dairy matrices: Implications for defining molecular markers of cell integrity. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2017.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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35
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Wang H, Bédard E, Prévost M, Camper AK, Hill VR, Pruden A. Methodological approaches for monitoring opportunistic pathogens in premise plumbing: A review. WATER RESEARCH 2017; 117:68-86. [PMID: 28390237 PMCID: PMC5693313 DOI: 10.1016/j.watres.2017.03.046] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/19/2017] [Accepted: 03/22/2017] [Indexed: 05/06/2023]
Abstract
Opportunistic premise (i.e., building) plumbing pathogens (OPPPs, e.g., Legionella pneumophila, Mycobacterium avium complex, Pseudomonas aeruginosa, Acanthamoeba, and Naegleria fowleri) are a significant and growing source of disease. Because OPPPs establish and grow as part of the native drinking water microbiota, they do not correspond to fecal indicators, presenting a major challenge to standard drinking water monitoring practices. Further, different OPPPs present distinct requirements for sampling, preservation, and analysis, creating an impediment to their parallel detection. The aim of this critical review is to evaluate the state of the science of monitoring OPPPs and identify a path forward for their parallel detection and quantification in a manner commensurate with the need for reliable data that is informative to risk assessment and mitigation. Water and biofilm sampling procedures, as well as factors influencing sample representativeness and detection sensitivity, are critically evaluated with respect to the five representative bacterial and amoebal OPPPs noted above. Available culturing and molecular approaches are discussed in terms of their advantages, limitations, and applicability. Knowledge gaps and research needs towards standardized approaches are identified.
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Affiliation(s)
- Hong Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Emilie Bédard
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Anne K Camper
- Center for Biofilm Engineering and Department of Civil Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Vincent R Hill
- Waterborne Disease Prevention Branch, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
| | - Amy Pruden
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
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36
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Collins S, Stevenson D, Walker J, Bennett A. Evaluation ofLegionellareal-time PCR against traditional culture for routine and public health testing of water samples. J Appl Microbiol 2017; 122:1692-1703. [DOI: 10.1111/jam.13461] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 11/29/2022]
Affiliation(s)
- S. Collins
- Biosafety Air and Water Microbiology Group; Public Health England; Porton Down Salisbury UK
| | - D. Stevenson
- Biosafety Air and Water Microbiology Group; Public Health England; Porton Down Salisbury UK
| | - J. Walker
- Biosafety Air and Water Microbiology Group; Public Health England; Porton Down Salisbury UK
| | - A. Bennett
- Biosafety Air and Water Microbiology Group; Public Health England; Porton Down Salisbury UK
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37
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Liao C, Zhao Y, Wang L. Establishment and Validation of RNA-Based Predictive Models for Understanding Survival of Vibrio parahaemolyticus in Oysters Stored at Low Temperatures. Appl Environ Microbiol 2017; 83:e02765-16. [PMID: 28087532 PMCID: PMC5335536 DOI: 10.1128/aem.02765-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/04/2017] [Indexed: 12/22/2022] Open
Abstract
This study developed RNA-based predictive models describing the survival of Vibrio parahaemolyticus in Eastern oysters (Crassostrea virginica) during storage at 0, 4, and 10°C. Postharvested oysters were inoculated with a cocktail of five V. parahaemolyticus strains and were then stored at 0, 4, and 10°C for 21 or 11 days. A real-time reverse transcription-PCR (RT-PCR) assay targeting expression of the tlh gene was used to evaluate the number of surviving V. parahaemolyticus cells, which was then used to establish primary molecular models (MMs). Before construction of the MMs, consistent expression levels of the tlh gene at 0, 4, and 10°C were confirmed, and this gene was used to monitor the survival of the total V. parahaemolyticus cells. In addition, the tdh and trh genes were used for monitoring the survival of virulent V. parahaemolyticus Traditional models (TMs) were built based on data collected using a plate counting method. From the MMs, V. parahaemolyticus populations had decreased 0.493, 0.362, and 0.238 log10 CFU/g by the end of storage at 0, 4, and 10°C, respectively. Rates of reduction of V. parahaemolyticus shown in the TMs were 2.109, 1.579, and 0.894 log10 CFU/g for storage at 0, 4, and 10°C, respectively. Bacterial inactivation rates (IRs) estimated with the TMs (-0.245, -0.152, and -0.121 log10 CFU/day, respectively) were higher than those estimated with the MMs (-0.134, -0.0887, and -0.0732 log10 CFU/day, respectively) for storage at 0, 4, and 10°C. Higher viable V. parahaemolyticus numbers were predicted using the MMs than using the TMs. On the basis of this study, RNA-based predictive MMs are the more accurate and reliable models and can prevent false-negative results compared to TMs.IMPORTANCE One important method for validating postharvest techniques and for monitoring the behavior of V. parahaemolyticus is to establish predictive models. Unfortunately, previous predictive models established based on plate counting methods or on DNA-based PCR can underestimate or overestimate the number of surviving cells. This study developed and validated RNA-based molecular predictive models to describe the survival of V. parahaemolyticus in oysters during low-temperature storage (0, 4, and 10°C). The RNA-based predictive models show the advantage of being able to count all of the culturable, nonculturable, and stressed cells. By using primers targeting the tlh gene and pathogenesis-associated genes (tdh and trh), real-time RT-PCR can evaluate the total surviving V. parahaemolyticus population as well as differentiate the pathogenic ones from the total population. Reliable and accurate predictive models are very important for conducting risk assessment and management of pathogens in food.
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Affiliation(s)
- Chao Liao
- Food Microbiology and Safety Lab, Department of Animal Sciences, Auburn University, Auburn, Alabama, USA
| | - Yong Zhao
- Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
| | - Luxin Wang
- Food Microbiology and Safety Lab, Department of Animal Sciences, Auburn University, Auburn, Alabama, USA
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Nguyen LDN, Deschaght P, Merlin S, Loywick A, Audebert C, Van Daele S, Viscogliosi E, Vaneechoutte M, Delhaes L. Effects of Propidium Monoazide (PMA) Treatment on Mycobiome and Bacteriome Analysis of Cystic Fibrosis Airways during Exacerbation. PLoS One 2016; 11:e0168860. [PMID: 28030619 PMCID: PMC5193350 DOI: 10.1371/journal.pone.0168860] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 12/07/2016] [Indexed: 02/06/2023] Open
Abstract
Introduction and Purpose Propidium monoazide (PMA)-pretreatment has increasingly been applied to remove the bias from dead or damaged cell artefacts, which could impact the microbiota analysis by high-throughput sequencing. Our study aimed to determine whether a PMA-pretreatment coupled with high-throughput sequencing analysis provides a different picture of the airway mycobiome and bacteriome. Results and Discussion We compared deep-sequencing data of mycobiota and microbiota of 15 sputum samples from 5 cystic fibrosis (CF) patients with and without prior PMA-treatment of the DNA-extracts. PMA-pretreatment had no significant effect on the entire and abundant bacterial community (genera expressed as operational taxonomic units (OTUs) with a relative abundance greater than or equal to 1%), but caused a significant difference in the intermediate community (less than 1%) when analyzing the alpha biodiversity Simpson index (p = 0.03). Regarding PMA impact on the airway mycobiota evaluated for the first time here; no significant differences in alpha diversity indexes between PMA-treated and untreated samples were observed. Regarding beta diversity analysis, the intermediate communities also differed more dramatically than the total and abundant ones when studying both mycobiome and bacteriome. Our results showed that only the intermediate (or low abundance) population diversity is impacted by PMA-treatment, and therefore that abundant taxa are mostly viable during acute exacerbation in CF. Given such a cumbersome protocol (PMA-pretreatment coupled with high-throughput sequencing), we discuss its potential interest within the follow-up of CF patients. Further studies using PMA-pretreatment are warranted to improve our “omic” knowledge of the CF airways.
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Affiliation(s)
- Linh Do Ngoc Nguyen
- Institut Pasteur de Lille, Center for Infection and Immunity of Lille (CIIL), INSERM U1019, CNRS UMR 8204, University of Lille, Lille, France
| | - Pieter Deschaght
- Laboratory for Bacteriology Research, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium
| | - Sophie Merlin
- GenesDiffusion, Douai, France
- PEGASE, Biosciences, Institut Pasteur de Lille, Lille, France
| | - Alexandre Loywick
- GenesDiffusion, Douai, France
- PEGASE, Biosciences, Institut Pasteur de Lille, Lille, France
| | - Christophe Audebert
- GenesDiffusion, Douai, France
- PEGASE, Biosciences, Institut Pasteur de Lille, Lille, France
| | - Sabine Van Daele
- Department of Pediatrics and Genetics, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium
| | - Eric Viscogliosi
- Institut Pasteur de Lille, Center for Infection and Immunity of Lille (CIIL), INSERM U1019, CNRS UMR 8204, University of Lille, Lille, France
| | - Mario Vaneechoutte
- Laboratory for Bacteriology Research, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium
| | - Laurence Delhaes
- Institut Pasteur de Lille, Center for Infection and Immunity of Lille (CIIL), INSERM U1019, CNRS UMR 8204, University of Lille, Lille, France
- Parasitology-Medical Mycology Department, Regional Hospital Center, Faculty of Medicine, Lille, France
- * E-mail:
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Designing primers and evaluation of the efficiency of propidium monoazide - Quantitative polymerase chain reaction for counting the viable cells of Lactobacillus gasseri and Lactobacillus salivarius. J Food Drug Anal 2016; 25:533-542. [PMID: 28911639 PMCID: PMC9328820 DOI: 10.1016/j.jfda.2016.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/21/2016] [Accepted: 10/30/2016] [Indexed: 01/12/2023] Open
Abstract
The purpose of this study is to evaluate the efficiency of using propidium monoazide (PMA) real-time quantitative polymerase chain reaction (qPCR) to count the viable cells of Lactobacillus gasseri and Lactobacillus salivarius in probiotic products. Based on the internal transcription spacer and 23S rRNA genes, two primer sets specific for these two Lactobacillus species were designed. For a probiotic product, the total deMan Rogosa Sharpe plate count was 8.65 ± 0.69 log CFU/g, while for qPCR, the cell counts of L. gasseri and L. salivarius were 8.39 ± 0.14 log CFU/g and 8.57 ± 0.24 log CFU/g, respectively. Under the same conditions, for its heat-killed product, qPCR counts for L. gasseri and L. salivarius were 6.70 ± 0.16 log cells/g and 7.67 ± 0.20 log cells/g, while PMA-qPCR counts were 5.33 ± 0.18 log cells/g and 5.05 ± 0.23 log cells/g, respectively. For cell dilutions with a viable cell count of 8.5 log CFU/mL for L. gasseri and L. salivarius, after heat killing, the PMA-qPCR count for both Lactobacillus species was near 5.5 log cells/mL. When the PMA-qPCR counts of these cell dilutions were compared before and after heat killing, although some DNA might be lost during the heat killing, significant qPCR signals from dead cells, i.e., about 4–5 log cells/mL, could not be reduced by PMA treatment. Increasing PMA concentrations from 100 μM to 200 μM or light exposure time from 5 minutes to 15 minutes had no or, if any, only minor effect on the reduction of qPCR signals from their dead cells. Thus, to differentiate viable lactic acid bacterial cells from dead cells using the PMA-qPCR method, the efficiency of PMA to reduce the qPCR signals from dead cells should be notable.
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Azeredo J, Azevedo NF, Briandet R, Cerca N, Coenye T, Costa AR, Desvaux M, Di Bonaventura G, Hébraud M, Jaglic Z, Kačániová M, Knøchel S, Lourenço A, Mergulhão F, Meyer RL, Nychas G, Simões M, Tresse O, Sternberg C. Critical review on biofilm methods. Crit Rev Microbiol 2016; 43:313-351. [PMID: 27868469 DOI: 10.1080/1040841x.2016.1208146] [Citation(s) in RCA: 541] [Impact Index Per Article: 67.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.
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Affiliation(s)
- Joana Azeredo
- a CEB ? Centre of Biological Engineering, LIBRO, Laboratórios de Biofilmes Rosário Oliveira, University of Minho Campus de Gualtar , Braga , Portugal
| | - Nuno F Azevedo
- b LEPABE, Department of Chemical Engineering, Faculty of Engineering , University of Porto , Porto , Portugal
| | - Romain Briandet
- c Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay , Jouy-en-Josas , France
| | - Nuno Cerca
- a CEB ? Centre of Biological Engineering, LIBRO, Laboratórios de Biofilmes Rosário Oliveira, University of Minho Campus de Gualtar , Braga , Portugal
| | - Tom Coenye
- d Laboratory of Pharmaceutical Microbiology , Ghent University , Ghent , Belgium
| | - Ana Rita Costa
- a CEB ? Centre of Biological Engineering, LIBRO, Laboratórios de Biofilmes Rosário Oliveira, University of Minho Campus de Gualtar , Braga , Portugal
| | - Mickaël Desvaux
- e INRA Centre Auvergne-Rhône-Alpes , UR454 Microbiologie , Saint-Genès Champanelle , France
| | - Giovanni Di Bonaventura
- f Department of Medical, Oral, and Biotechnological Sciences, and Center of Excellence on Aging and Translational Medicine (CeSI-MeT) , "G. d'Annunzio" University of Chieti-Pescara , Chieti , Italy
| | - Michel Hébraud
- e INRA Centre Auvergne-Rhône-Alpes , UR454 Microbiologie , Saint-Genès Champanelle , France
| | - Zoran Jaglic
- g Department of Food and Feed Safety, Laboratory of Food Bacteriology , Veterinary Research Institute , Brno , Czech Republic
| | - Miroslava Kačániová
- h Department of Microbiology, Faculty of Biotechnology and Food Sciences , Slovak University of Agriculture in Nitra , Nitra , Slovakia
| | - Susanne Knøchel
- i Department of Food Science (FOOD) , University of Copenhagen , Frederiksberg C , Denmark
| | - Anália Lourenço
- j Department of Computer Science , University of Vigo , Ourense , Spain
| | - Filipe Mergulhão
- b LEPABE, Department of Chemical Engineering, Faculty of Engineering , University of Porto , Porto , Portugal
| | - Rikke Louise Meyer
- k Aarhus University, Interdisciplinary Nanoscience Center (iNANO) , Aarhus , Denmark
| | - George Nychas
- l Agricultural University of Athens, Lab of Microbiology and Biotechnology of Foods , Athens , Greece
| | - Manuel Simões
- b LEPABE, Department of Chemical Engineering, Faculty of Engineering , University of Porto , Porto , Portugal
| | - Odile Tresse
- m LUNAM Université, Oniris, SECALIM UMR1024 INRA , Université de Nantes , Nantes , France
| | - Claus Sternberg
- n Department of Biotechnology and Biomedicine , Technical University of Denmark , Lyngby, Denmark
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Scaturro M, Fontana S, Dell’eva I, Helfer F, Marchio M, Stefanetti MV, Cavallaro M, Miglietta M, Montagna MT, De Giglio O, Cuna T, Chetti L, Sabattini MAB, Carlotti M, Viggiani M, Stenico A, Romanin E, Bonanni E, Ottaviano C, Franzin L, Avanzini C, Demarie V, Corbella M, Cambieri P, Marone P, Rota MC, Bella A, Ricci ML. A multicenter study of viable PCR using propidium monoazide to detect Legionella in water samples. Diagn Microbiol Infect Dis 2016; 85:283-288. [DOI: 10.1016/j.diagmicrobio.2016.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/21/2016] [Accepted: 04/11/2016] [Indexed: 11/26/2022]
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Kirschner AK. Determination of viable legionellae in engineered water systems: Do we find what we are looking for? WATER RESEARCH 2016; 93:276-288. [PMID: 26928563 PMCID: PMC4913838 DOI: 10.1016/j.watres.2016.02.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 05/06/2023]
Abstract
In developed countries, legionellae are one of the most important water-based bacterial pathogens caused by management failure of engineered water systems. For routine surveillance of legionellae in engineered water systems and outbreak investigations, cultivation-based standard techniques are currently applied. However, in many cases culture-negative results are obtained despite the presence of viable legionellae, and clinical cases of legionellosis cannot be traced back to their respective contaminated water source. Among the various explanations for these discrepancies, the presence of viable but non-culturable (VBNC) Legionella cells has received increased attention in recent discussions and scientific literature. Alternative culture-independent methods to detect and quantify legionellae have been proposed in order to complement or even substitute the culture method in the future. Such methods should detect VBNC Legionella cells and provide a more comprehensive picture of the presence of legionellae in engineered water systems. However, it is still unclear whether and to what extent these VBNC legionellae are hazardous to human health. Current risk assessment models to predict the risk of legionellosis from Legionella concentrations in the investigated water systems contain many uncertainties and are mainly based on culture-based enumeration. If VBNC legionellae should be considered in future standard analysis, quantitative risk assessment models including VBNC legionellae must be proven to result in better estimates of human health risk than models based on cultivation alone. This review critically evaluates current methods to determine legionellae in the VBNC state, their potential to complement the standard culture-based method in the near future, and summarizes current knowledge on the threat that VBNC legionellae may pose to human health.
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Affiliation(s)
- Alexander K.T. Kirschner
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
- Interuniversity Cooperation Centre for Water & Health, Austria
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene Kinderspitalgasse 16, A-1090 Vienna, Austria . URL: http://www.waterandhealth.at
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Heise J, Nega M, Alawi M, Wagner D. Propidium monoazide treatment to distinguish between live and dead methanogens in pure cultures and environmental samples. J Microbiol Methods 2015; 121:11-23. [PMID: 26656002 DOI: 10.1016/j.mimet.2015.12.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/02/2015] [Accepted: 12/02/2015] [Indexed: 11/16/2022]
Abstract
In clinical trials investigating human health and in the analysis of microbial communities in cultures and natural environments, it is a substantial challenge to differentiate between living, potentially active communities and dead cells. The DNA-intercalating dye propidium monoazide (PMA) enables the selective masking of DNA from dead, membrane-compromised cells immediately before DNA extraction. In the present study, we evaluated for the first time a PMA treatment for methanogenic archaea in cultures and particle-rich environmental samples. Using microscopic analyses, we confirmed the applicability of the LIVE/DEAD(®) BacLight™ kit to methanogenic archaea and demonstrated the maintenance of intact cell membranes of methanogens in the presence of PMA. Although strain-specific differences in the efficiency of PMA treatment to methanogenic archaea were observed, we developed an optimal procedure using 130 μM PMA and 5min of photo-activation with blue LED light. The results showed that the effectiveness of the PMA treatment strongly depends on the texture of the sediment/soil: silt and clay-rich sediments represent a challenge at all concentrations, whereas successful suppression of DNA from dead cells with compromised membranes was possible for low particle loads of sandy soil (total suspended solids (TSS)≤200 mg mL(-1)). Conclusively, we present two strategies to overcome the problem of insufficient light activation of PMA caused by the turbidity effect (shielding) in particle-rich environmental samples by (i) dilution of the particle-rich sample and (ii) detachment of the cells and the free DNA from the sediment prior to a PMA treatment. Both strategies promise to be usable options for distinguishing living cells and free DNA in complex environmental samples.
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Affiliation(s)
- Janine Heise
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany
| | - Marcella Nega
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany
| | - Mashal Alawi
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany.
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Collins S, Jorgensen F, Willis C, Walker J. Real-time PCR to supplement gold-standard culture-based detection of Legionella
in environmental samples. J Appl Microbiol 2015. [DOI: 10.1111/jam.12911] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Collins
- Public Health England; Biosafety Investigation Unit; Salisbury UK
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - F. Jorgensen
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - C. Willis
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - J. Walker
- Public Health England; Biosafety Investigation Unit; Salisbury UK
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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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Enumeration of viable non-culturable Vibrio cholerae using propidium monoazide combined with quantitative PCR. J Microbiol Methods 2015; 115:147-52. [PMID: 26001818 DOI: 10.1016/j.mimet.2015.05.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 11/22/2022]
Abstract
The well-known human pathogenic bacterium, Vibrio cholerae, can enter a physiologically viable but non-culturable (VBNC) state under stress conditions. The differentiation of VBNC cells and nonviable cells is essential for both disease prevention and basic research. Among all the methods for detecting viability, propidium monoazide (PMA) combined with real-time PCR is popular because of its specificity, sensitivity, and speed. However, the effect of PMA treatment is not consistent and varies among different species and conditions. In this study, with an initial cell concentration of 1×10(8) CFU/ml, time and dose-effect relationships of different PMA treatments were evaluated via quantitative real-time PCR using live cell suspensions, dead cell suspensions and VBNC cell suspensions of V. cholerae O1 El Tor strain C6706. The results suggested that a PMA treatment of 20 μM PMA for 20 min was optimal under our conditions. This treatment maximized the suppression of the PCR signal from membrane-compromised dead cells but had little effect on the signal from membrane-intact live cells. In addition to the characteristics of PMA treatment itself, the initial concentration of the targeted bacteria showed a significant negative influence on the stability of PMA-PCR assay in this study. We developed a strategy that mimicked a 1×10(8) CFU/ml cell concentration with dead bacteria of a different bacterial species, the DNA of which cannot be amplified using the real time PCR primers. With this strategy, our optimal approach successfully overcame the impact of low cell density and generated stable and reliable results for counting viable cells of V. cholerae in the VBNC state.
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Abstract
Orthopaedic infections are complex conditions that require immediate diagnosis and accurate identification of the causative organisms to facilitate appropriate management. Conventional methodologies for diagnosis of these infections sometimes lack accuracy or sufficient rapidity. Molecular diagnostics is an emerging area of bench-to-bedside research in orthopaedic infections. Examples of promising molecular diagnostics include measurement of a specific biomarker in the synovial fluid, polymerase chain reaction-based detection of bacterial genes, and metabolomic determination of responses to orthopaedic infection.
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Tavernier S, Coenye T. Quantification of Pseudomonas aeruginosa in multispecies biofilms using PMA-qPCR. PeerJ 2015; 3:e787. [PMID: 25755923 PMCID: PMC4349053 DOI: 10.7717/peerj.787] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 02/04/2015] [Indexed: 11/20/2022] Open
Abstract
Multispecies biofilms are an important healthcare problem and may lead to persistent infections. These infections are difficult to treat, as cells in a biofilm are highly resistant to antimicrobial agents. While increasingly being recognized as important, the properties of multispecies biofilms remain poorly studied. In order to do so, the quantification of the individual species is needed. The current cultivation-based approaches can lead to an underestimation of the actual cell number and are time-consuming. In the present study we set up a culture-independent approach based on propidium monoazide qPCR (PMA-qPCR) to quantify Pseudomonas aeruginosa in a multispecies biofilm. As a proof of concept, we explored the influence of the combined presence of Staphylococcus aureus, Streptococcus anginosus and Burkholderia cenocepacia on the antimicrobial susceptibility of P. aeruginosa using this PMA-qPCR approach.
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Affiliation(s)
- Sarah Tavernier
- Laboratory of Pharmaceutical Microbiology, Ghent University , Ghent , Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University , Ghent , Belgium
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