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Sauget M, Richard M, Chassagne S, Hocquet D, Bertrand X, Jeanvoine A. Validation of quantitative real-time PCR for detection of Legionella pneumophila in hospital water networks. J Hosp Infect 2023:S0195-6701(23)00195-0. [PMID: 37353007 DOI: 10.1016/j.jhin.2023.06.010] [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: 04/25/2023] [Revised: 06/08/2023] [Accepted: 06/10/2023] [Indexed: 06/25/2023]
Abstract
BACKGROUND Rapid monitoring of Legionella pneumophila (Lp) is essential to reduce the risk of Legionnaires' disease in healthcare facilities. However, culture results take at least eight days, delaying the implementation of corrective measures. Here, we assessed the performance of a qPCR method and determined qPCR action thresholds for the detection of Lp in hospital hot water networks (HWNs). METHODS Hot water samples (n=459) were collected from a hospital HWNs. Lp were quantified using iQ-Check® Quanti real-time PCR Quantification kits (Bio-Rad) and the results were compared with those of culture. qPCR thresholds corresponding to the culture action thresholds of 10 and 1,000 CFU/L were determined on a training dataset and validated on an independent dataset. RESULTS Lp concentrations measured by culture and qPCR were correlated for both the training dataset (Spearman's correlation coefficient ρ = 0.687, p-value < 0.0001) and the validation dataset (ρ = 0.661, p-value < 0.0001). Lp qPCR positivity thresholds corresponding to culture action thresholds of 10 CFU/L was 91 genome units (GU) per liter (sensitivity, 86.4%; negative predictive value - NPV, 93.3%) and that corresponding to culture action thresholds of 1,000 CFU/L was 1,048 GU/L (sensitivity, 100%; NPV, 100%). CONCLUSION Detection of Lp by qPCR could be implemented with confidence in hospitals as a complement to culture in the monitoring strategy to speed up the implementation of corrective measures.
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Affiliation(s)
- Marlène Sauget
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France; Centre de Ressources Biologiques, Centre Hospitalier Universitaire de Besançon, Besançon, France.
| | - Marion Richard
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France; Centre de Ressources Biologiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Sophie Chassagne
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Didier Hocquet
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France; Chrono-environnement, Université de Franche-Comté, CNRS, Besançon, France; Centre de Ressources Biologiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Xavier Bertrand
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France; Chrono-environnement, Université de Franche-Comté, CNRS, Besançon, France
| | - Audrey Jeanvoine
- Hygiène Hospitalière, Centre Hospitalier Universitaire de Besançon, Besançon, France
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2
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Kim T, Zhao X, LaPara TM, Hozalski RM. Flushing Temporarily Improves Microbiological Water Quality for Buildings Supplied with Chloraminated Surface Water but Has Little Effect for Groundwater Supplies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5453-5463. [PMID: 36952669 DOI: 10.1021/acs.est.2c08123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microbial communities in premise plumbing systems were investigated after more than 2 months of long-term stagnation, during a subsequent flushing event, and during post-flush stagnation. Water samples were collected from showers in buildings supplied with chlorinated groundwater, untreated groundwater, and chloraminated surface water. The building supplied with chlorinated groundwater generally had the lowest bacterial concentrations across all sites (ranging from below quantification limit to 5.2 log copies/L). For buildings supplied with untreated groundwater, bacterial concentrations (5.0 to 7.6 log copies/L) and microbial community diversity index (ACE) values were consistent throughout sampling. Nontuberculous mycobacteria (NTM) and Legionella pneumophila were not detected in any groundwater-supplied buildings. Total bacteria, Legionella spp., and NTM were abundant in the surface water-supplied buildings following long-term stagnation (up to 7.6, 6.2, and 7.6 log copies/L, respectively). Flushing decreased these concentrations by ∼1 to >4 log units and reduced microbial community diversity, but the communities largely recovered within a week of post-flush stagnation. The results suggest that buildings supplied with disinfected surface water are more likely than buildings supplied with treated or untreated groundwater to experience deleterious changes in microbiological water quality during stagnation and that the water quality improvements from flushing with chloraminated water, while substantial, are short-lived.
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Affiliation(s)
- Taegyu Kim
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
| | - Xiaotian Zhao
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
| | - Timothy M LaPara
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
- Biotechnology Institute, University of Minnesota Twin Cities, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Raymond M Hozalski
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota Twin Cities, 500 Pillsbury Drive S.E., Minneapolis, Minnesota 55455, United States
- Biotechnology Institute, University of Minnesota Twin Cities, 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
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3
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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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Capuano R, Mansi A, Paba E, Marcelloni AM, Chiominto A, Proietto AR, Gordiani A, Catini A, Paolesse R, Tranfo G, Di Natale C. A Pilot Study for Legionella pneumophila Volatilome Characterization Using a Gas Sensor Array and GC/MS Techniques. SENSORS (BASEL, SWITZERLAND) 2023; 23:1401. [PMID: 36772440 PMCID: PMC9920052 DOI: 10.3390/s23031401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Legionellosis is a generic term describing the pneumonic (Legionnaires' disease, LD) and non-pneumonic (Pontiac fever, PF) forms of infection with bacteria belonging to the genus Legionella. Currently, the techniques used to detect Legionella spp. in water samples have certain limitations and drawbacks, and thus, there is a need to identify new tools to carry out low-cost and rapid analysis. In this regard, several studies demonstrated that a volatolomics approach rapidly detects and discriminates different species of microorganisms via their volatile signature. In this paper, the volatile organic compounds (VOCs) pattern emitted in vitro by Legionella pneumophila cultures is characterized and compared to those produced by other Legionella species and by Pseudomonas aeruginosa, using a gas sensor array and gas chromatograph mass spectrometer (GC-MS). Bacterial cultures were measured at the 3rd and 7th day after the incubation. Sensor array data analyzed via the K-nearest neighbours (k-NN) algorithm showed a sensitivity to Legionella pneumophila identification at around 89%. On the other hand, GC-MS identified a bouquet of VOCs, mainly alcohols and ketones, that enable the differentiation of Legionella pneumophila in respect to other waterborne microorganisms.
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Affiliation(s)
- Rosamaria Capuano
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
- Interdepartmental Centre for Volatilomics ‘A. D’Amico’, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
| | - Antonella Mansi
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Emilia Paba
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Anna Maria Marcelloni
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Alessandra Chiominto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Anna Rita Proietto
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Andrea Gordiani
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Alexandro Catini
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
- Interdepartmental Centre for Volatilomics ‘A. D’Amico’, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
| | - Roberto Paolesse
- Interdepartmental Centre for Volatilomics ‘A. D’Amico’, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
- Department of Chemical Science and Technology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
| | - Giovanna Tranfo
- Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Italian Workers’ Compensation Authority (INAIL), Via Fontana Candida 1, Monte Porzio Catone, 00078 Rome, Italy
| | - Corrado Di Natale
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
- Interdepartmental Centre for Volatilomics ‘A. D’Amico’, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
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Yuan K, Jurado-Sánchez B, Escarpa A. Nanomaterials meet surface-enhanced Raman scattering towards enhanced clinical diagnosis: a review. J Nanobiotechnology 2022; 20:537. [PMID: 36544151 PMCID: PMC9771791 DOI: 10.1186/s12951-022-01711-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
Surface-enhanced Raman scattering (SERS) is a very promising tool for the direct detection of biomarkers for the diagnosis of i.e., cancer and pathogens. Yet, current SERS strategies are hampered by non-specific interactions with co-existing substances in the biological matrices and the difficulties of obtaining molecular fingerprint information from the complex vibrational spectrum. Raman signal enhancement is necessary, along with convenient surface modification and machine-based learning to address the former issues. This review aims to describe recent advances and prospects in SERS-based approaches for cancer and pathogens diagnosis. First, direct SERS strategies for key biomarker sensing, including the use of substrates such as plasmonic, semiconductor structures, and 3D order nanostructures for signal enhancement will be discussed. Secondly, we will illustrate recent advances for indirect diagnosis using active nanomaterials, Raman reporters, and specific capture elements as SERS tags. Thirdly, critical challenges for translating the potential of the SERS sensing techniques into clinical applications via machine learning and portable instrumentation will be described. The unique nature and integrated sensing capabilities of SERS provide great promise for early cancer diagnosis or fast pathogens detection, reducing sanitary costs but most importantly allowing disease prevention and decreasing mortality rates.
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Affiliation(s)
- Kaisong Yuan
- Bio-Analytical Laboratory, Shantou University Medical College, No. 22, Xinling Road, Shantou, 515041, China
- Department of Analytical Chemistry, Physical Chemistry, and Chemical Engineering, University of Alcala, Alcala de Henares, 28802, Madrid, Spain
| | - Beatriz Jurado-Sánchez
- Department of Analytical Chemistry, Physical Chemistry, and Chemical Engineering, University of Alcala, Alcala de Henares, 28802, Madrid, Spain
- Chemical Research Institute "Andrés M. del Río", University of Alcala, Alcala de Henares, 28802, Madrid, Spain
| | - Alberto Escarpa
- Department of Analytical Chemistry, Physical Chemistry, and Chemical Engineering, University of Alcala, Alcala de Henares, 28802, Madrid, Spain
- Chemical Research Institute "Andrés M. del Río", University of Alcala, Alcala de Henares, 28802, Madrid, Spain
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Tiwari N, Bansal M, Santhiya D, Sharma JG. Insights into microbial diversity on plastisphere by multi-omics. Arch Microbiol 2022; 204:216. [PMID: 35316402 DOI: 10.1007/s00203-022-02806-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 12/20/2022]
Abstract
Plastic pollution is a major concern in marine environment as it takes many years to degrade and is one of the greatest threats to marine life. Plastic surface, referred to as plastisphere, provides habitat for growth and proliferation of various microorganisms. The discovery of these microbes is necessary to identify significant genes, enzymes and bioactive compounds that could help in bioremediation and other commercial applications. Conventional culture techniques have been successful in identifying few microbes from these habitats, leaving majority of them yet to be explored. As such, to recognize the vivid genetic diversity of microbes residing in plastisphere, their structure and corresponding ecological roles within the ecosystem, an emerging technique, called metagenomics has been explored. The technique is expected to provide hitherto unknown information on microbes from the plastisphere. Metagenomics along with next generation sequencing provides comprehensive knowledge on microbes residing in plastisphere that identifies novel microbes for plastic bioremediation, bioactive compounds and other potential benefits. The following review summarizes the efficiency of metagenomics and next generation sequencing technology over conventionally used methods for culturing microbes. It attempts to illustrate the workflow mechanism of metagenomics to elucidate diverse microbial profiles. Further, importance of integrated multi-omics techniques has been highlighted in discovering microbial ecology residing on plastisphere for wider applications.
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Affiliation(s)
- Neha Tiwari
- Department of Biotechnology, Delhi Technological University, Delhi, India
| | - Megha Bansal
- Department of Biotechnology, Delhi Technological University, Delhi, India
| | - Deenan Santhiya
- Department of Applied Chemistry, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi, 110042, India.
| | - Jai Gopal Sharma
- Department of Biotechnology, Delhi Technological University, Delhi, India
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7
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A Model System for Sensitive Detection of Viable E. coli Bacteria Combining Direct Viability PCR and a Novel Microarray-Based Detection Approach. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9120357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We established an innovative approach that included direct, viability, and nested PCR for rapid and reliable identification of the fecal indicator organism Escherichia coli (E. coli). Direct PCR enabled successful amplification of the target uidA gene, omitting a prior DNA isolation or purification step. Furthermore, we applied viability PCR (v-PCR) to ensure the detection of only relevant viable bacterial cells. The principle involves the binding of propidium monoazide (PMA), a selective nucleic acid intercalating dye, to accessible DNA of heat killed bacteria cells and, consequently, allows viable and heat killed E. coli cells to be discriminated. To ensure high sensitivity, direct v-PCR was followed by a nested PCR step. The resulting amplicons were analyzed by a rapid 30 min microarray-based DNA hybridization assay for species-specific DNA detection of E. coli. A positive signal was indicated by enzymatically generated silver nanoparticle deposits, which served as robust endpoint signals allowing an immediate visual readout. The presented novel protocol allows the detection of 1 × 101 viable E. coli cells per PCR run.
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8
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Chiang ELC, Lee S, Medriano CA, Li L, Bae S. Assessment of physiological responses of bacteria to chlorine and UV disinfection using a plate count method, flow cytometry and viability PCR. J Appl Microbiol 2021; 132:1788-1801. [PMID: 34637587 DOI: 10.1111/jam.15325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 11/28/2022]
Abstract
AIMS This study aimed to investigate the physiological responses of two gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and two gram-positive bacteria (Enterococcus faecalis and Bacillus sphaericus) to ultraviolet (UV) and chlorine disinfection. METHODS AND RESULTS Bacterial inactivation by UV and chlorine disinfection were evaluated with a plate count method for culturability, FCM and PMA-qPCR for membrane integrity and DyeTox13-qPCR for enzymatic activity, respectively. Both UV and chorine disinfection caused complete loss of culturability while membrane integrity remained intact after UV disinfection. Both DyeTox13-qPCR and PMA-qPCR showed high ΔCt values up to 8.9 after chlorine disinfection, indicating that both methods were able to distinguish non-treated from chlorine-treated cells. Although PMA-qPCR could not differentiate membrane integrity of cells on UV exposure, DyeTox13-qPCR showed significant differences in ΔCt values of 5.05 and 10.4 for gram-negative (E. coli) and gram-positive (Enterococcus) bacteria, respectively. However, DyeTox13-qPCR for gram-negative bacteria displayed relatively small differences in ΔCt values compared with gram-positive bacteria. CONCLUSION UV and chlorine disinfection led to changes in physiological state of gram-negative and gram-positive bacteria. Particularly, UV disinfection could induce active but non-culturable (ABNC) for gram-negative bacteria and dormant cell for gram-positive bacteria where intact cells no longer showed the enzymatic activity. SIGNIFICANCE AND IMPACT OF THE STUDY UV and chlorine are commonly used to disinfect water, food and fomites to inactivate pathogenic bacteria. However, a viable but non-culturable (VBNC) state of bacteria induced by disinfection may underestimate the health risks because of the potential resuscitation of VBNC cells. This study highlighted that bacteria could undergo different physiological (ABNC or dormant) states during UV and chlorine disinfection. In addition, viability PCR techniques could provide insight into the changes in physiological states during disinfection processes.
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Affiliation(s)
- Elaine L C Chiang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Seunguk Lee
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Carl A Medriano
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Liyan Li
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Sungwoo Bae
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
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Walker JT, McDermott PJ. Confirming the Presence of Legionella pneumophila in Your Water System: A Review of Current Legionella Testing Methods. J AOAC Int 2021; 104:1135-1147. [PMID: 33484265 PMCID: PMC8378878 DOI: 10.1093/jaoacint/qsab003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/24/2022]
Abstract
Legionnaires' disease has been recognized since 1976 and Legionella pneumophila still accounts for more than 95% of cases. Approaches in countries, including France, suggest that focusing risk reduction specifically on L. pneumophila is an effective strategy, as detecting L. pneumophila has advantages over targeting multiple species of Legionella. In terms of assays, the historically accepted plate culture method takes 10 days for confirmed Legionella spp. results, has variabilities which affect trending and comparisons, requires highly trained personnel to identify colonies on a plate in specialist laboratories, and does not recover viable-but-non-culturable bacteria. PCR is sensitive, specific, provides results in less than 24 h, and determines the presence/absence of Legionella spp. and/or L. pneumophila DNA. Whilst specialist personnel and laboratories are generally required, there are now on-site PCR options, but there is no agreement on comparing genome units to colony forming units and action limits. Immunomagnetic separation assays are culture-independent, detect multiple Legionella species, and results are available in 24 h, with automated processing options. Field-use lateral flow devices provide presence/absence determination of L. pneumophila serogroup 1 where sufficient cells are present, but testing potable waters is problematic. Liquid culture most probable number (MPN) assays provide confirmed L. pneumophila results in 7 days that are equivalent to or exceed plate culture, are robust and reproducible, and can be performed in a variety of laboratory settings. MPN isolates can be obtained for epidemiological investigations. This accessible, non-technical review will be of particular interest to building owners, operators, risk managers, and water safety groups and will enable them to make informed decisions to reduce the risk of L. pneumophila.
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Keserue HA, Cornillie N, Ehlert AK, Mills DC, Morger D, Piffaretti A, Schaffhauser DF, Schwyzer II. Validation of the Legionella pneumophila SG1 DETECT Kit for Quantification of Legionella pneumophila Serogroup 1 Bacteria in Potable Waters, Process Waters, and Surface Waters: AOAC Performance Tested MethodSM 052002. J AOAC Int 2021; 104:776-789. [PMID: 33609035 DOI: 10.1093/jaoacint/qsaa126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 11/12/2022]
Abstract
The L.p.SG1 DETECT Kit is a rapid, quantitative method for the detection and enumeration of Legionella pneumophila serogroup 1 (L.p. SG1) bacteria from different water matrixes. The method is based on a combination of immunomagnetic separation (IMS) and flow cytometric (FCM) quantification. To this end, the method employs magnetic particles conjugated to anti-L.p. SG1 antibodies for the IMS of the target bacteria from environmental matrices and fluorescently labeled anti-L.p. SG1 antibodies for subsequent quantification by FCM. The IMS can be performed either manually with a magnetic rack (rqmicro.MIMS) or automated with the rqmicro.STREAM sample preparation instrument. Compared to the reference method ISO 11731:2017, which is based on culturing and enumeration of colony forming units (CFU) on agar plates, and can take up to 10 days until results are available, analysis with the L.p. SG1 DETECT Kit is culture-independent and delivers results within 2 h. This Performance Tested Method validation study demonstrates a robust method with recoveries exceeding 69%, inclusivity of 100%, exclusivity of 97.2%, and a shelf life of at least 6 months at 4°C or 40 days at 25°C. The Limit of Detection (LOD) was determined at 21 CFU/L and the Limit of Quantification (LOQ) at 80 CFU/L for potable water using the rqmicro.STREAM. The matrix study across three different types of water matrixes (potable, surface, and industrial process water), demonstrates superior repeatability and reproducibility, as well as equivalent or even superior detection of L.p. SG1 bacteria compared to the standard ISO 11731 method.
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Affiliation(s)
| | | | | | | | - Damien Morger
- rqmicro AG, Brandstrasse 24, 8952 Schlieren, Switzerland
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Huang C, Mahboubat BY, Ding Y, Yang Q, Wang J, Zhou M, Wang X. Development of a rapid Salmonella detection method via phage-conjugated magnetic bead separation coupled with real-time PCR quantification. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111075] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Hortelano I, Moreno MY, García-Hernández J, Ferrús MA. Optimization of pre- treatments with Propidium Monoazide and PEMAX™ before real-time quantitative PCR for detection and quantification of viable Helicobacter pylori cells. J Microbiol Methods 2021; 185:106223. [PMID: 33872638 DOI: 10.1016/j.mimet.2021.106223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/17/2022]
Abstract
Accurate detection of H. pylori in different environmental and clinical samples is essential for public health strtdudies. Now, a big effort is being made to design PCR methodologies that allow for the detection of viable and viable but non-culturable (VBNC) H. pylori cells, by achieving complete exclusion of dead cells amplification signals. The use of DNA intercalating dyes has been proposed. However, its efficacy is still not well determined. In this study, we aimed to test the suitability of PMA and PEMAX™ dyes used prior to qPCR for only detecting viable cells of H. pylori. Their efficiency was evaluated with cells submitted to different disinfection treatments and confirmed by the absence of growth on culture media and by LIVE/DEAD counts. Our results indicated that an incubation period of 5 min for both, PMA and PEMAX™, did not affect viable cells. Our study also demonstrated that results obtained by using intercalating dyes may vary depending on the cell stress conditions. In all dead cell's samples, both PMA and PEMAX™ pre-qPCR treatments decreased the amplification signal (>103 Genomic Units (GU)), although none of them allowed for its disappearance confirming that intercalating dyes, although useful for screening purposes, cannot be considered as universal viability markers. To investigate the applicability of the method specifically to detect H. pylori cells in environmental samples, PMA-qPCR was performed on samples containing the different morphological and viability states that H. pylori can acquire in environment. The optimized PMA-qPCR methodology showed to be useful to detect mostly (but not only) viable forms, regardless the morphological state of the cell.
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Affiliation(s)
- Irene Hortelano
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain.
| | - María Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain
| | | | - María Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, 46022, Valencia, Spain.
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Sciuto EL, Laganà P, Filice S, Scalese S, Libertino S, Corso D, Faro G, Coniglio MA. Environmental Management of Legionella in Domestic Water Systems: Consolidated and Innovative Approaches for Disinfection Methods and Risk Assessment. Microorganisms 2021; 9:577. [PMID: 33799845 PMCID: PMC8001549 DOI: 10.3390/microorganisms9030577] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/31/2022] Open
Abstract
Legionella is able to remain in water as free-living planktonic bacteria or to grow within biofilms that adhere to the pipes. It is also able to enter amoebas or to switch into a viable but not culturable (VBNC) state, which contributes to its resistance to harsh conditions and hinders its detection in water. Factors regulating Legionella growth, such as environmental conditions, type and concentration of available organic and inorganic nutrients, presence of protozoa, spatial location of microorganisms, metal plumbing components, and associated corrosion products are important for Legionella survival and growth. Finally, water treatment and distribution conditions may affect each of these factors. A deeper comprehension of Legionella interactions in water distribution systems with the environmental conditions is needed for better control of the colonization. To this purpose, the implementation of water management plans is the main prevention measure against Legionella. A water management program requires coordination among building managers, health care providers, and Public Health professionals. The review reports a comprehensive view of the state of the art and the promising perspectives of both monitoring and disinfection methods against Legionella in water, focusing on the main current challenges concerning the Public Health sector.
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Affiliation(s)
- Emanuele Luigi Sciuto
- Azienda Ospedaliero Universitaria Policlinico “G. Rodolico-San Marco”, Via Sofia 78, 95123 Catania, Italy;
| | - Pasqualina Laganà
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Messina, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Torre Biologica 3p, AOU ‘G. Martino, Via C. Valeria, s.n.c., 98125 Messina, Italy;
| | - Simona Filice
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Silvia Scalese
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Sebania Libertino
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Domenico Corso
- Istituto per la Microelettronica e Microsistemi–Consiglio Nazionale delle Ricerche (CNR-IMM), Ottava Strada 5, 95121 Catania, Italy; (S.F.); (S.S.); (S.L.); (D.C.)
| | - Giuseppina Faro
- Azienda Sanitaria Provinciale di Catania, Via S. Maria La Grande 5, 95124 Catania, Italy;
| | - Maria Anna Coniglio
- Azienda Ospedaliero Universitaria Policlinico “G. Rodolico-San Marco”, Via Sofia 78, 95123 Catania, Italy;
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Catania, Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University of Catania, Via Sofia 87, 95123 Catania, Italy
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14
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Fischer FB, Schmutz C, Gaia V, Mäusezahl D. Legionnaires' Disease on the Rise in Switzerland: A Denominator-Based Analysis of National Diagnostic Data, 2007-2016. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17197343. [PMID: 33050023 PMCID: PMC7579383 DOI: 10.3390/ijerph17197343] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 12/17/2022]
Abstract
The risk of falling ill with Legionnaires' disease (LD) is suggested to increase, but the global burden of disease is unknown due to a lack of appropriate diagnosis and surveillance systems. In Switzerland, the number of LD cases, captured by the National Notification System for Infectious Diseases, has more than doubled since 2008. This study aims to investigate this increase, contextualizing disease surveillance data with denominator data, which is not routinely available, i.e., the number of tests performed for Legionella spp. We collected the testing data for Legionella spp. of 14 Swiss diagnostic laboratories and calculated the positivity, defined as the proportion of the number of positive tests to the number of tests performed. The number of positive tests increased proportionally to the number of tests performed; hence, the positivity remained stable. However, the cause of the increase in test volume is unclear and has a large impact on the interpretation of the positivity curve. Further, the test outcome was found to be dependent on regional determinants, and the diagnostic method applied. The lack of understanding if and at which stage LD is considered in current case management of pneumonia patients limits the interpretation of observed heterogeneities in incidence or underestimation of LD in Switzerland. The absence of (or non-adherence to) existing guidelines and the heterogeneity in diagnostic testing hampers the comparison of data in the Swiss public health context. Therefore, diagnostic procedures should be harmonised across Switzerland and adherence to national LD management guidelines supported.
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Affiliation(s)
- Fabienne B. Fischer
- Swiss Tropical and Public Health Institute, 4001 Basel, Switzerland; (F.B.F.); (C.S.)
- Faculty of Science, University of Basel, 4002 Basel, Switzerland
| | - Claudia Schmutz
- Swiss Tropical and Public Health Institute, 4001 Basel, Switzerland; (F.B.F.); (C.S.)
- Faculty of Science, University of Basel, 4002 Basel, Switzerland
| | - Valeria Gaia
- National Reference Center for Legionella, Service of Microbiology, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland;
| | - Daniel Mäusezahl
- Swiss Tropical and Public Health Institute, 4001 Basel, Switzerland; (F.B.F.); (C.S.)
- Faculty of Science, University of Basel, 4002 Basel, Switzerland
- Correspondence: ; Tel.: +41-61-284-8178
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15
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Inoue H. Interpreting the Results of the Conventional Plate Culture and Gene Detection Methods for Legionella Detection in Environmental Water Samples. Biocontrol Sci 2020; 25:121-129. [PMID: 32938841 DOI: 10.4265/bio.25.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The conventional plate culture method is widely used as a method for detection of Legionella in environmental water samples, but to obtain results takes more than a week. Because it is much quicker, the gene detection method has become widespread as an alternative detection method. However, the results of gene detection and plate culture methods may differ even when the same sample is examined; the gene detection method shows a higher detection ratio than the plate culture method. The reason for this difference is that the plate culture method detects Legionella cells that have the ability to form colonies on an agar plate, whereas the gene detection method detects any Legionella genes present regardless of the state of the Legionella. In this paper, we consider the factors that cause differences between the results of the plate culture and gene detection methods, and how to interpret the results of each.
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16
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Water as a Source of Antimicrobial Resistance and Healthcare-Associated Infections. Pathogens 2020; 9:pathogens9080667. [PMID: 32824770 PMCID: PMC7459458 DOI: 10.3390/pathogens9080667] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/13/2022] Open
Abstract
Healthcare-associated infections (HAIs) are one of the most common patient complications, affecting 7% of patients in developed countries each year. The rise of antimicrobial resistant (AMR) bacteria has been identified as one of the biggest global health challenges, resulting in an estimated 23,000 deaths in the US annually. Environmental reservoirs for AMR bacteria such as bed rails, light switches and doorknobs have been identified in the past and addressed with infection prevention guidelines. However, water and water-related devices are often overlooked as potential sources of HAI outbreaks. This systematic review examines the role of water and water-related devices in the transmission of AMR bacteria responsible for HAIs, discussing common waterborne devices, pathogens, and surveillance strategies. AMR strains of previously described waterborne pathogens including Pseudomonas aeruginosa, Mycobacterium spp., and Legionella spp. were commonly isolated. However, methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae that are not typically associated with water were also isolated. Biofilms were identified as a hot spot for the dissemination of genes responsible for survival functions. A limitation identified was a lack of consistency between environmental screening scope, isolation methodology, and antimicrobial resistance characterization. Broad universal environmental surveillance guidelines must be developed and adopted to monitor AMR pathogens, allowing prediction of future threats before waterborne infection outbreaks occur.
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17
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Amalfitano S, Levantesi C, Copetti D, Stefani F, Locantore I, Guarnieri V, Lobascio C, Bersani F, Giacosa D, Detsis E, Rossetti S. Water and microbial monitoring technologies towards the near future space exploration. WATER RESEARCH 2020; 177:115787. [PMID: 32315899 DOI: 10.1016/j.watres.2020.115787] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
Space exploration is demanding longer lasting human missions and water resupply from Earth will become increasingly unrealistic. In a near future, the spacecraft water monitoring systems will require technological advances to promptly identify and counteract contingent events of waterborne microbial contamination, posing health risks to astronauts with lowered immune responsiveness. The search for bio-analytical approaches, alternative to those applied on Earth by cultivation-dependent methods, is pushed by the compelling need to limit waste disposal and avoid microbial regrowth from analytical carryovers. Prospective technologies will be selected only if first validated in a flight-like environment, by following basic principles, advantages, and limitations beyond their current applications on Earth. Starting from the water monitoring activities applied on the International Space Station, we provide a critical overview of the nucleic acid amplification-based approaches (i.e., loop-mediated isothermal amplification, quantitative PCR, and high-throughput sequencing) and early-warning methods for total microbial load assessments (i.e., ATP-metry, flow cytometry), already used at a high readiness level aboard crewed space vehicles. Our findings suggest that the forthcoming space applications of mature technologies will be necessarily bounded by a compromise between analytical performances (e.g., speed to results, identification depth, reproducibility, multiparametricity) and detrimental technical requirements (e.g., reagent usage, waste production, operator skills, crew time). As space exploration progresses toward extended missions to Moon and Mars, miniaturized systems that also minimize crew involvement in their end-to-end operation are likely applicable on the long-term and suitable for the in-flight water and microbiological research.
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Affiliation(s)
- Stefano Amalfitano
- Water Research Institute - National Research Council of Italy (IRSA-CNR), Via Salaria Km 29,300, 00015, Monterotondo, Roma, Italy.
| | - Caterina Levantesi
- Water Research Institute - National Research Council of Italy (IRSA-CNR), Via Salaria Km 29,300, 00015, Monterotondo, Roma, Italy
| | - Diego Copetti
- Water Research Institute - National Research Council of Italy (IRSA-CNR), Via del Mulino 19, 20861, Brugherio, Monza-Brianza, Italy
| | - Fabrizio Stefani
- Water Research Institute - National Research Council of Italy (IRSA-CNR), Via del Mulino 19, 20861, Brugherio, Monza-Brianza, Italy
| | - Ilaria Locantore
- Thales Alenia Space Italia SpA, Strada Antica di Collegno, 253 - 10146, Turin, Italy
| | - Vincenzo Guarnieri
- Thales Alenia Space Italia SpA, Strada Antica di Collegno, 253 - 10146, Turin, Italy
| | - Cesare Lobascio
- Thales Alenia Space Italia SpA, Strada Antica di Collegno, 253 - 10146, Turin, Italy
| | - Francesca Bersani
- Centro Ricerche SMAT, Società Metropolitana Acque Torino S.p.A., C.so Unità d'Italia 235/3, 10127, Torino, Italy
| | - Donatella Giacosa
- Centro Ricerche SMAT, Società Metropolitana Acque Torino S.p.A., C.so Unità d'Italia 235/3, 10127, Torino, Italy
| | - Emmanouil Detsis
- European Science Foundation, 1 quai Lezay Marnésia, BP 90015, 67080, Strasbourg Cedex, France
| | - Simona Rossetti
- Water Research Institute - National Research Council of Italy (IRSA-CNR), Via Salaria Km 29,300, 00015, Monterotondo, Roma, Italy
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18
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Fisher KE, Wickenberg LP, Leonidas LF, Ranz AA, Habib MA, Buford RM, McCoy WF. Next Day Legionella PCR: a highly reliable negative screen for Legionella in the built environment. JOURNAL OF WATER AND HEALTH 2020; 18:345-357. [PMID: 32589620 DOI: 10.2166/wh.2020.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The opportunistic, waterborne pathogen Legionella caused 9,933 cases of Legionnaires' disease in 2018 in the United States (CDC.gov). The incidence of Legionnaires' disease can be reduced by maintaining clean building water systems through water management programs (WMPs). WMPs often include validation testing to confirm the control of bacteria, but the traditional culture method for enumerating Legionella requires 10-14 days to obtain results. A rapid DNA extraction developed by Phigenics and a real-time PCR negative screen for the genus Legionella provided results the day after sampling. This study evaluated the Next Day Legionella PCR (Phigenics, LLC) compared with the traditional culture method (ISO 11731) on 11,125 building water samples for approximately 1 year. Two DNA extraction methods (Methods 1 and 2) were compared. The negative predictive value (NPV) of the Next Day Legionella PCR in comparison to traditional culture for Method 1 was 99.95%, 99.92%, 99.85%, and 99.17% at >10, >2, >1, and >0.1 CFU/ml limits of detection, respectively. The improved DNA extraction (Method 2) increased the NPV to 100% and 99.88% at >1 and >0.1 CFU/ml, respectively. These results demonstrate the reliability of the genus-level Legionella PCR negative screen to predict culture-negative water samples.
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Affiliation(s)
- Katherine E Fisher
- Phigenics Research and Innovation Team, Nevada Center for Applied Research, Reno, NV, USA E-mail:
| | - Leah P Wickenberg
- Phigenics Research and Innovation Team, Nevada Center for Applied Research, Reno, NV, USA E-mail:
| | - Lesley F Leonidas
- Phigenics Analytical Services Laboratory (PASL), Warrenville, IL, USA
| | - Anna A Ranz
- Phigenics Analytical Services Laboratory (PASL), Fayetteville, AR, USA
| | - Michelle A Habib
- Phigenics Analytical Services Laboratory (PASL), Warrenville, IL, USA
| | - Rafael M Buford
- Phigenics Analytical Services Laboratory (PASL), Fayetteville, AR, USA
| | - William F McCoy
- Phigenics Research and Innovation Team, Nevada Center for Applied Research, Reno, NV, USA E-mail:
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19
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Yang M, Cousineau A, Liu X, Luo Y, Sun D, Li S, Gu T, Sun L, Dillow H, Lepine J, Xu M, Zhang B. Direct Metatranscriptome RNA-seq and Multiplex RT-PCR Amplicon Sequencing on Nanopore MinION - Promising Strategies for Multiplex Identification of Viable Pathogens in Food. Front Microbiol 2020; 11:514. [PMID: 32328039 PMCID: PMC7160302 DOI: 10.3389/fmicb.2020.00514] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/10/2020] [Indexed: 12/20/2022] Open
Abstract
Viable pathogenic bacteria are major biohazards that pose a significant threat to food safety. Despite the recent developments in detection platforms, multiplex identification of viable pathogens in food remains a major challenge. A novel strategy is developed through direct metatranscriptome RNA-seq and multiplex RT-PCR amplicon sequencing on Nanopore MinION to achieve real-time multiplex identification of viable pathogens in food. Specifically, this study reports an optimized universal Nanopore sample extraction and library preparation protocol applicable to both Gram-positive and Gram-negative pathogenic bacteria, demonstrated using a cocktail culture of E. coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes, which were selected based on their impact on economic loss or prevalence in recent outbreaks. Further evaluation and validation confirmed the accuracy of direct metatranscriptome RNA-seq and multiplex RT-PCR amplicon sequencing using Sanger sequencing and selective media. The study also included a comparison of different bioinformatic pipelines for metatranscriptomic and amplicon genomic analysis. MEGAN without rRNA mapping showed the highest accuracy of multiplex identification using the metatranscriptomic data. EPI2ME also demonstrated high accuracy using multiplex RT-PCR amplicon sequencing. In addition, a systemic comparison was drawn between Nanopore sequencing of the direct metatranscriptome RNA-seq and RT-PCR amplicons. Both methods are comparable in accuracy and time. Nanopore sequencing of RT-PCR amplicons has higher sensitivity, but Nanopore metatranscriptome sequencing excels in read length and dealing with complex microbiome and non-bacterial transcriptome backgrounds.
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Affiliation(s)
- Manyun Yang
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, United States
| | | | - Xiaobo Liu
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, United States
| | - Yaguang Luo
- Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD, United States
| | - Daniel Sun
- New England Biolabs, Inc., Ipswich, MA, United States
- Department of Chemistry, Brandeis University, Waltham, MA, United States
| | - Shaohua Li
- New England Biolabs, Inc., Ipswich, MA, United States
- U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Tingting Gu
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, United States
| | - Luo Sun
- New England Biolabs, Inc., Ipswich, MA, United States
| | - Hayden Dillow
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, United States
| | - Jack Lepine
- Biomolecular Characterization Lab, University of Massachusetts Lowell, Lowell, MA, United States
| | - Mingqun Xu
- New England Biolabs, Inc., Ipswich, MA, United States
| | - Boce Zhang
- Department of Biomedical and Nutritional Sciences, University of Massachusetts, Lowell, MA, United States
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20
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Cates EL, Torkzadeh H. Can incorporation of UVC LEDs into showerheads prevent opportunistic respiratory pathogens? - Microbial behavior and device design considerations. WATER RESEARCH 2020; 168:115163. [PMID: 31614239 DOI: 10.1016/j.watres.2019.115163] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 09/17/2019] [Accepted: 10/05/2019] [Indexed: 06/10/2023]
Abstract
Respiratory infections from opportunistic bacterial pathogens (OBPs) have heightened research interests in drinking water distribution systems, premise plumbing, and point-of-use technologies. In particular, biofilm growth in showerheads increases OBP content, and inhalation of shower aerosols is a major exposure route for Legionellae and Mycobacteria infections. Incorporation of UVC LEDs into showerheads has thus been proposed as a point-of-use option for healthcare facilities. Herein we have examined incongruities between the nature of OBP contamination in shower water and the hypothetical application of conventional UV disinfection engineering concepts. Effective UV dosing within showerheads must overcome significant shielding effects imparted by the biological matrices in which common OBPs reside, including biofilm particles and protozoan hosts. Furthermore, prevention of biofilm growth in showerhead interiors requires a different UV irradiation approach and is lacking in established design parameters. Development of showerhead devices is also likely to face a trade-off between bathing functionality and simpler form factors that are more conducive to internal UV irradiation.
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Affiliation(s)
- Ezra L Cates
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, 29625, USA.
| | - Hamed Torkzadeh
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, 29625, USA
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21
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Assessment of predatory bacteria and prey interactions using culture-based methods and EMA-qPCR. Microbiol Res 2019; 228:126305. [DOI: 10.1016/j.micres.2019.126305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/19/2019] [Accepted: 07/20/2019] [Indexed: 10/26/2022]
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22
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Ditommaso S, Giacomuzzi M, Memoli G, Cavallo R, Curtoni A, Avolio M, Silvestre C, Zotti CM. Reduction of turnaround time for non-tuberculous mycobacteria detection in heater-cooler units by propidium monoazide-real-time polymerase chain reaction. J Hosp Infect 2019; 104:365-373. [PMID: 31628958 DOI: 10.1016/j.jhin.2019.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Invasive non-tuberculous mycobacteria (NTM) infections are emerging worldwide in patients undergoing open-chest cardiac bypass surgery exposed to contaminated heater-cooler units (HCUs). Although this outbreak has been investigated by culturing bacteria isolated from HCU aerosol and water samples, these conventional methods have low-analytic sensitivity, high rates of sample contamination, and long turnaround time. AIM To develop a simple and effective method to detect NTM in HCUs by real-time polymerase chain reaction (PCR), with a short laboratory turnaround time and reliable culture results. METHODS A total of 281 water samples collected from various HCUs at seven Italian hospitals were simultaneously screened for NTM by a propidium monoazide (PMA)-PCR assay and by conventional culture testing. The results were analysed with culture testing as the reference method. FINDINGS (i) The agreement between culture testing and PMA-PCR was 85.0% with a cycle threshold (CT) cut-off value of <38 vs 80.0% with a CT of <43, with a moderate Cohen's κ-coefficient; (ii) the CT cut-off value of <42 was deemed more suitable for predicting positive specimens; (iii) given the low concentration of target DNA in water samples, the minimum volume to be tested was 1 L. CONCLUSION The use of PMA-PCR for fast detection of NTM from environmental samples is highly recommended in order to ascertain whether HCUs may represent a potential source of human exposure to NTM. This reliable and simple method reduces laboratory turnaround time compared to conventional methods (one to two days vs eight weeks, respectively), thereby improving control strategies and effective management of HCUs.
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Affiliation(s)
- S Ditommaso
- Department of Public Health and Pediatrics, University of Turin, Turin, Italy.
| | - M Giacomuzzi
- Department of Public Health and Pediatrics, University of Turin, Turin, Italy
| | - G Memoli
- Department of Public Health and Pediatrics, University of Turin, Turin, Italy
| | - R Cavallo
- Department of Public Health and Pediatrics, University of Turin, Turin, Italy; Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - A Curtoni
- Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - M Avolio
- Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Turin, Italy
| | - C Silvestre
- AOU Città della salute e della Scienza, Turin, Italy
| | - C M Zotti
- Department of Public Health and Pediatrics, University of Turin, Turin, Italy
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23
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LeChevallier MW. Occurrence of culturable
Legionella pneumophila
in drinking water distribution systems. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/aws2.1139] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Ahmed S, Liwak-Muir U, Walker D, Zoldowski A, Mears A, Golovan S, Mohr S, Lem P, Harder C. Validation and in-field testing of a new on-site qPCR system for quantification of Legionella pneumophila according to ISO/TS 12869:2012 in HVAC cooling towers. JOURNAL OF WATER AND HEALTH 2019; 17:237-253. [PMID: 30942774 DOI: 10.2166/wh.2019.252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Legionella pneumophila, found in engineered water systems such as HVAC cooling towers, poses a significant public health risk. Culture, though routinely used to quantify L. pneumophila, has several disadvantages including long turnaround time, low sensitivity, and inter-laboratory variability. In this study, we validated the performance of an on-site quantitative polymerase chain reaction (qPCR) detection system for L. pneumophila in accordance with International Standards Organization Technical Specification 12869:2012. We evaluated specificity, limit of detection and quantification, and calibration curve linearity. Additionally, we evaluated whole system recovery and robustness using samples taken from taps and evaporative cooling towers. We then compared the system's performance against laboratory culture and laboratory qPCR across 53 cooling towers in a 12-week in-field study. We found that concordance between on-site qPCR and culture was both laboratory- and site/sample-dependent. Comparison of laboratory qPCR with on-site qPCR revealed that laboratory results were highly variable and showed little concordance. Some discordance may be explained by time delay between sample collection and testing ('shipping effect') which may lead to inaccurate reporting. Overall, our study highlights the value of on-site qPCR detection of L. pneumophila, demonstrates that laboratories are prone to misreporting results due to shipping effects, and reveals significant discordance between laboratory qPCR and culture.
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Affiliation(s)
- Shaimaa Ahmed
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Urszula Liwak-Muir
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Danielle Walker
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Agnes Zoldowski
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Alan Mears
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Sergey Golovan
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Steve Mohr
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Paul Lem
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
| | - Chris Harder
- Spartan Bioscience Inc., 2934 Baseline Road, Suite 500, Ottawa, ON K2H 1B2, Canada E-mail:
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25
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Chaudhry R, Sreenath K, Agrawal SK, Valavane A. Legionella and Legionnaires' disease: Time to explore in India. Indian J Med Microbiol 2019; 36:324-333. [PMID: 30429383 DOI: 10.4103/ijmm.ijmm_18_298] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Legionella pneumophila was first recognised as a fatal cause of pneumonia more than four decades ago, during the 1976-American Legion convention in Philadelphia, USA. Legionella spp. continue to cause disease outbreaks of public health significance, and at present, Legionnaires' disease (LD) has emerged as an important cause of community and hospital-acquired pneumonia. Parallel to this, the understanding of LD has also increased exponentially. However, the disease is likely to be underreported in many countries because of the dearth of common definitions, diagnostic tests and active surveillance systems. In this review, we outline the basic concepts of Legionella including clinical presentations, epidemiology, laboratory diagnosis and the status of LD in India. This article also summarises the progress of research related to Legionella in this country, identifying the research gaps and discussing priorities to explore this unexplored pathogen in India.
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Affiliation(s)
- Rama Chaudhry
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - K Sreenath
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Sonu Kumari Agrawal
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Arvind Valavane
- Department of Microbiology, Indira Gandhi Medical College and Research Institute, Puducherry, India
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Caicedo C, Rosenwinkel KH, Exner M, Verstraete W, Suchenwirth R, Hartemann P, Nogueira R. Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review. WATER RESEARCH 2019; 149:21-34. [PMID: 30445393 DOI: 10.1016/j.watres.2018.10.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.
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Affiliation(s)
- C Caicedo
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
| | - K-H Rosenwinkel
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany
| | - M Exner
- University of Bonn, Institute for Hygiene and Public Health, Bonn, Germany
| | - W Verstraete
- Ghent University, CMET, Ghent, and Avecom, Wondelgem, Belgium
| | - R Suchenwirth
- Public Health Office of Lower Saxony, Hannover, Germany
| | - P Hartemann
- Faculty of Medicine, Department of Environment and Public Health, Nancy University-CHU Nancy, Vandoeuvre Les Nancy, France
| | - R Nogueira
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
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Bonetta S, Pignata C, Bonetta S, Meucci L, Giacosa D, Marino E, Gorrasi I, Gilli G, Carraro E. Effectiveness of a neutral electrolysed oxidising water (NEOW) device in reducing Legionella pneumophila in a water distribution system: A comparison between culture, qPCR and PMA-qPCR detection methods. CHEMOSPHERE 2018; 210:550-556. [PMID: 30029147 DOI: 10.1016/j.chemosphere.2018.07.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 05/22/2023]
Abstract
Disinfection of hot water systems is critical for reducing Legionnaires' disease in high-risk buildings. The use of neutral electrolysed oxidising water (NEOW) is a promising method for the control of microorganisms in hot water systems. However, full-scale evaluations of the efficacy of NEOW devices to control Legionella pneumophila are currently lacking. The aim of this study was to assess the effectiveness of a NEOW device in reducing L. pneumophila in a hotel water network. Water samples (n = 67) were collected from different sites of a hotel distribution system before and after the installation of the NEOW device at the 1st, 4th, 8th and 12th week. Detection of L. pneumophila was performed comparing culture, qPCR and PMA-qPCR methods. Total bacterial counts (22 °C and 37 °C), Pseudomonas spp. and physico-chemical parameters were also monitored. The NEOW treatment resulted in a reduction of the amount of L. pneumophila positive samples (-32%) and of the number of heavily contaminated points (>104 CFU/L and >103 CFU/L) (-100% and -96%, respectively). Treatment maintained L. pneumophila at low levels (<102 CFU/L), which do not require specific intervention measures. The effectiveness of the disinfection system was also confirmed by PMA-qPCR (p < 0.001). The use of PMA resulted in a signal decrease in almost all samples upon the disinfection treatment. The NEOW disinfection device appears to be a promising approach to reduce the colonisation of hot water systems by L. pneumophila; however, further investigations are needed to ascertain its efficiency over longer time periods.
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Affiliation(s)
- Sara Bonetta
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy.
| | - Cristina Pignata
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy
| | - Silvia Bonetta
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy
| | - Lorenza Meucci
- Società Metropolitana Acque Torino S.P.A, C.so XI Febbraio 14, 10152, Torino, Italy
| | - Donatella Giacosa
- Società Metropolitana Acque Torino S.P.A, C.so XI Febbraio 14, 10152, Torino, Italy
| | - Elena Marino
- Società Metropolitana Acque Torino S.P.A, C.so XI Febbraio 14, 10152, Torino, Italy
| | - Ilaria Gorrasi
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy
| | - Giorgio Gilli
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy
| | - Elisabetta Carraro
- Department of Public Health and Pediatrics, University of Torino, Piazza Polonia 94, 10126, Torino, Italy
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Uyguner Demirel CS, Birben NC, Bekbolet M. A comprehensive review on the use of second generation TiO 2 photocatalysts: Microorganism inactivation. CHEMOSPHERE 2018; 211:420-448. [PMID: 30077938 DOI: 10.1016/j.chemosphere.2018.07.121] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/04/2018] [Accepted: 07/21/2018] [Indexed: 05/12/2023]
Abstract
Photocatalytic disinfection practices have been applied for decades and attract current interest along with the developments in synthesis of novel photocatalysts. A survey based investigation was performed for elucidation of photocatalytic treatment details as well as disinfection mechanism of microorganisms. The present work brings significant information on the utilization of second generation TiO2 photocatalysts for inactivation of microorganisms typically using E. coli as the model microorganism. Special interest was devoted to the role of organic matrix either generated during treatment or as a natural component. Studies on photocatalytic disinfection were extensively reviewed and evaluated with respect to basic operational parameters related to photocatalysis, and types and properties of microorganisms investigated. Degradation mechanism and behavior of microorganisms towards reactive oxygen species during disinfection and organic matrix effects were also addressed. For successful utilization and effective assessment of visible light active photocatalysts, standard protocols for disinfection activity testing have to be set. Further improvement of the efficiency of these materials would be promising for future applications in water treatment processes.
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Affiliation(s)
| | - Nazmiye Cemre Birben
- Bogazici University, Institute of Environmental Sciences, 34342, Bebek, Istanbul, Turkey.
| | - Miray Bekbolet
- Bogazici University, Institute of Environmental Sciences, 34342, Bebek, Istanbul, Turkey.
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Valavane A, Chaudhry R, Malhotra P. Multiplex polymerase chain reaction of genetic markers for detection of potentially pathogenic environmental Legionella pneumophila isolates. Indian J Med Res 2018; 146:392-400. [PMID: 29355148 PMCID: PMC5793476 DOI: 10.4103/ijmr.ijmr_623_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background & objectives: Genomic constitution of the bacterium Legionella pneumophila plays an important role in providing them a pathogenic potential. Here, we report the standardization and application of multiplex polymerase chain reaction (PCR) for the detection of molecular markers of pathogenic potential in L. pneumophila in hospital environment. Methods: Culture of the standard strains of L. pneumophila was performed in buffered charcoal-yeast extract agar with L-cysteine at pH 6.9. Primers were designed for multiplex PCR, and standardization for the detection of five markers annotated to L. pneumophila plasmid pLPP (11A2), lipopolysaccharide synthesis (19H4), CMP-N-acetylneuraminic acid synthetase (10B12), conjugative coupling factor (24B1) and hypothetical protein (8D6) was done. A total of 195 water samples and 200 swabs were collected from the hospital environment. The bacterium was isolated from the hospital environment by culture and confirmed by 16S rRNA gene PCR and restriction enzyme analysis. A total of 45 L. pneumophila isolates were studied using the standardized multiplex PCR. Results: The PCR was sensitive to detect 0.1 ng/μl DNA and specific for the two standard strains used in the study. Of the 45 hospital isolates tested, 11 isolates had four markers, 12 isolates had three markers, 10 isolates had two markers, nine isolates had one marker and three isolates had none of the markers. None of the isolates had all the five markers. Interpretation & conclusions: The findings of this study showed the presence of gene markers of pathogenic potential of the bacterium L. pneumophila. However, the genomic constitution of the environmental isolates should be correlated with clinical isolates to prove their pathogenic potential. Rapid diagnostic methods such as multiplex PCR reported here, for elucidating gene markers, could help in future epidemiological studies of bacterium L. pneumophila.
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Affiliation(s)
- Arvind Valavane
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Rama Chaudhry
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Pawan Malhotra
- International Centre for Genetic Engineering & Biotechnology, New Delhi, India
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Kanders L, Beier M, Nogueira R, Nehrenheim E. Sinks and sources of anammox bacteria in a wastewater treatment plant - screening with qPCR. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 78:441-451. [PMID: 30101779 DOI: 10.2166/wst.2018.318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The deammonification process, which includes nitritation and anammox bacteria, is an energy-efficient nitrogen removal process. Starting up an anammox process in a wastewater treatment plant (WWTP) is still widely believed to require external seeding of anammox bacteria. To demonstrate the principle of a non-seeded anammox start-up, anammox bacteria in potential sources must be quantified. In this study, seven digesters, their substrates and reject water were sampled and quantitative polymerase chain reaction (qPCR) was used to quantify both total and viable anammox bacteria. The results show that mesophilic digesters fed with nitrifying sludge (with high sludge ages) can be classified as a reliable source of anammox bacteria. Sludge hygienization and dewatering of digestate reduce the amount of anammox bacteria by one to two orders of magnitude and can be considered as a sink. The sampled reject waters contained on average >4.0 × 104 copies mL-1 and the majority of these cells (>87%) were viable cells. Furthermore, plants with side-stream anammox treatment appear to have higher overall quantities of anammox bacteria than those without such treatment. The present study contributes to the development of sustainable strategies for both start-up of anammox reactors and the possibility of improving microbial management in WWTPs.
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Affiliation(s)
- Linda Kanders
- Purac AB, Box 1146, SE-221 05 Lund, Sweden E-mail: ; School of Business, Society and Engineering, Mälardalen University, Box 883, SE-721 23 Västerås, Sweden
| | - Maike Beier
- Institute for Sanitary Engineering and Waste Management (ISAH), Leibniz Universitaet Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Regina Nogueira
- Institute for Sanitary Engineering and Waste Management (ISAH), Leibniz Universitaet Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Emma Nehrenheim
- School of Business, Society and Engineering, Mälardalen University, Box 883, SE-721 23 Västerås, Sweden
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Janssen KJH, Dirks JAMC, Dukers-Muijrers NHTM, Hoebe CJPA, Wolffs PFG. Review of Chlamydia trachomatis viability methods: assessing the clinical diagnostic impact of NAAT positive results. Expert Rev Mol Diagn 2018; 18:739-747. [PMID: 29987959 DOI: 10.1080/14737159.2018.1498785] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Chlamydia trachomatis (chlamydia) is the most commonly diagnosed bacterial sexually transmitted infection (STI) worldwide. The advancement of molecular techniques has made chlamydia diagnostics infinitely easier. However, molecular techniques lack the information on chlamydia viability. Where in routine diagnostics the detection of chlamydia DNA or RNA might suffice, in other patient scenarios, information on the viability of chlamydia might be essential. Areas covered: In this review, the authors discuss the specific strengths and limitations of currently available methods to evaluate chlamydia viability: conventional cell culture, messenger RNA (mRNA) detection and viability-PCR (V-PCR). PubMed and Google Scholar were searched with the following terms: Chlamydia trachomatis, Treatment failure, Anal chlamydia, Microbial viability, Culture, Viability-PCR, Messenger RNA, and Molecular diagnostics Expert commentary: Several techniques are currently available to determine chlamydia viability and thus the clinical relevance of a positive test result in clinical samples. Depending on the underlying research question, all three discussed techniques have their merits when testing for viability. However, mRNA methods show the most promise in determining the presence of a true infection, in case the chlamydia reticulate body can be specifically detected. Further research is needed to understand how to best apply viability testing in current chlamydia diagnostics.
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Affiliation(s)
- Kevin J H Janssen
- a Department of Medical Microbiology, Care and Public Health Research Institute (CAPHRI) , Maastricht University Medical Center (MUMC+) , Maastricht , The Netherlands
| | - Jeanne A M C Dirks
- a Department of Medical Microbiology, Care and Public Health Research Institute (CAPHRI) , Maastricht University Medical Center (MUMC+) , Maastricht , The Netherlands
| | - Nicole H T M Dukers-Muijrers
- a Department of Medical Microbiology, Care and Public Health Research Institute (CAPHRI) , Maastricht University Medical Center (MUMC+) , Maastricht , The Netherlands.,b Department of Sexual Health, Infectious Diseases and Environmental Health , South Limburg Public Health Service , Heerlen , The Netherlands
| | - Christian J P A Hoebe
- a Department of Medical Microbiology, Care and Public Health Research Institute (CAPHRI) , Maastricht University Medical Center (MUMC+) , Maastricht , The Netherlands.,b Department of Sexual Health, Infectious Diseases and Environmental Health , South Limburg Public Health Service , Heerlen , The Netherlands
| | - Petra F G Wolffs
- a Department of Medical Microbiology, Care and Public Health Research Institute (CAPHRI) , Maastricht University Medical Center (MUMC+) , Maastricht , The Netherlands
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Vondrakova L, Turonova H, Scholtz V, Pazlarova J, Demnerova K. Impact of various killing methods on EMA/PMA-qPCR efficacy. Food Control 2018. [DOI: 10.1016/j.foodcont.2017.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Knowledge to Predict Pathogens: Legionella pneumophila Lifecycle Critical Review Part I Uptake into Host Cells. WATER 2018. [DOI: 10.3390/w10020132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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34
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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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Dobrowsky PH, Khan S, Khan W. Resistance of Legionella and Acanthamoeba mauritaniensis to heat treatment as determined by relative and quantitative polymerase chain reactions. ENVIRONMENTAL RESEARCH 2017; 158:82-93. [PMID: 28609649 DOI: 10.1016/j.envres.2017.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/11/2017] [Accepted: 06/04/2017] [Indexed: 06/07/2023]
Abstract
Legionella and Acanthamoeba spp. persist in harvested rainwater pasteurized at high temperatures (> 72°C) and the interaction mechanisms exhibited between these organisms need to be elucidated. The resistance of two Legionella reference strains (Legionella pneumophila ATCC 33152 and Legionella longbeachae ATCC 33462), three environmental strains [Legionella longbeachae (env.), Legionella norrlandica (env.) and Legionella rowbothamii (env.)] and Acanthamoeba mauritaniensis ATCC 50676 to heat treatment (50-90°C) was determined by monitoring culturability and viability [ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR)]. The expression of metabolic and virulence genes of L. pneumophila ATCC 33152 (lolA, sidF, csrA) and L. longbeachae (env.) (lolA) in co-culture with A. mauritaniensis ATCC 50676 during heat treatment (50-90°C) was monitored using relative qPCR. While the culturability (CFU/mL) and viability (gene copies/mL) of the Legionella strains reduced significantly (p < 0.05) following heat treatment (60-90°C), L. longbeachae (env.) and L. pneumophila ATCC 33152 were culturable following heat treatment at 50-60°C. Metabolically active trophozoites and dormant cysts of A. mauritaniensis ATCC 50676 were detected at 50°C and 60-90°C, respectively. For L. pneumophila ATCC 33152, lolA expression remained constant, sidF expression increased and the expression of csrA decreased during co-culture with A. mauritaniensis ATCC 50676. For L. longbeachae (env.), while lolA was up-regulated at 50-70°C, expression was not detected at 80-90°C and in co-culture. In conclusion, while heat treatment may reduce the number of viable Legionella spp. in monoculture, results indicate that the presence of A. mauritaniensis increases the virulence of L. pneumophila during heat treatment. The virulence of Legionella spp. in co-culture with Acanthamoeba spp. should thus be monitored in water distribution systems where temperature (heat) is utilized for treatment.
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Affiliation(s)
- Penelope H Dobrowsky
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
| | - Sehaam Khan
- Faculty of Health and Applied Sciences, Namibia University of Science and Technology,13 Storch Street, Private Bag 13388, Windhoek, Namibia.
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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Samhan FA, Stedtfeld TM, Waseem H, Williams MR, Stedtfeld RD, Hashsham SA. On-filter direct amplification of Legionella pneumophila for rapid assessment of its abundance and viability. WATER RESEARCH 2017; 121:162-170. [PMID: 28527390 PMCID: PMC5525548 DOI: 10.1016/j.watres.2017.05.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/08/2017] [Accepted: 05/12/2017] [Indexed: 05/14/2023]
Abstract
Guidelines and regulations to control Legionella pneumophila in cooling water systems of large buildings are evolving due to the increasing number of outbreaks. Rapid, on-site, simple, and sensitive quantification methods that are also able to assess viability may be extremely useful in monitoring and control. Culture-based methods for measuring L. pneumophila may take 4-10 days and qPCR-based methods are also slow, requiring at least a day from sample to result, albeit mainly due to the need for sample transport to a centralized laboratory. This study reports a rapid isothermal amplification method for L. pneumophila concentration and detection with live/dead differentiation under field conditions. Using an on-filter direct amplification (i.e., amplification of cells without DNA extraction and purification) approach with propidium monoazide (PMA), and a real time isothermal amplification platform (Gene-Z), L. pneumophila could be detected in 1-2 h at ∼1 cfu/100 ml of tap water. Signature sequences from 16S rRNA and cadA genes were used as genetic markers for L. pneumophila and loop-mediated isothermal amplification (LAMP) primers were designed using Primer Explorer V4. Result were also compared with direct amplification of cells spiked into distilled, tap, and cooling water samples as well as extracted DNA by qPCR. This method may be useful to managers of cooling water systems in large buildings for rapid detection of L. pneumophila. The overall approach of on-site sample concentration, on-filter amplification, and live/dead differentiation may be extended to other organisms where analytical sensitivity and speed are equally important.
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Affiliation(s)
- Farag A Samhan
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
| | - Tiffany M Stedtfeld
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
| | - Hassan Waseem
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
| | - Maggie R Williams
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
| | - Robert D Stedtfeld
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
| | - Syed A Hashsham
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA; Center for Microbial Ecology, Michigan State University, East Lansing, MI, USA.
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Comparison of EMA-, PMA- and DNase qPCR for the determination of microbial cell viability. Appl Microbiol Biotechnol 2017; 101:7371-7383. [PMID: 28875372 DOI: 10.1007/s00253-017-8471-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/21/2017] [Accepted: 08/03/2017] [Indexed: 01/13/2023]
Abstract
Ethidium monoazide (EMA) quantitative polymerase chain reaction (qPCR), propidium monoazide (PMA)-qPCR and DNase treatment in combination with qPCR were compared for the determination of microbial cell viability. Additionally, varying EMA and PMA concentrations were analysed to determine which dye and concentration allowed for the optimal identification of viable cells. Viable, heat treated (70 °C for 15 min) and autoclaved cultures of Legionella pneumophila, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Enterococcus faecalis were utilised in the respective viability assays. Analysis of the viable and heat-treated samples indicated that variable log reductions were recorded for both EMA [log reductions ranging from 0.01 to 2.71 (viable) and 0.27 to 2.85 (heat treated)], PMA [log reductions ranging from 0.06 to 1.02 (viable) and 0.62 to 2.46 (heat treated)] and DNase treatment [log reductions ranging from 0.06 to 0.82 (viable) and 0.70 to 2.91 (heat treated)], in comparison to the no viability treatment controls. Based on the results obtained, 6 μM EMA and 50 μM PMA were identified as the optimal dye concentrations as low log reductions were recorded (viable and heat-treated samples) in comparison to the no viability treatment control. In addition, the results recorded for the 6 μM EMA concentration were comparable to the results obtained for both the 50 μM PMA and the DNase treatment. The use of EMA-qPCR (6 μM) may therefore allow for the rapid identification and quantification of multiple intact opportunistic pathogens in water sources, which would benefit routine water quality monitoring following disinfection treatment.
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Kober C, Niessner R, Seidel M. Quantification of viable and non-viable Legionella spp. by heterogeneous asymmetric recombinase polymerase amplification (haRPA) on a flow-based chemiluminescence microarray. Biosens Bioelectron 2017; 100:49-55. [PMID: 28863324 DOI: 10.1016/j.bios.2017.08.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/01/2017] [Accepted: 08/23/2017] [Indexed: 11/19/2022]
Abstract
Increasing numbers of legionellosis outbreaks within the last years have shown that Legionella are a growing challenge for public health. Molecular biological detection methods capable of rapidly identifying viable Legionella are important for the control of engineered water systems. The current gold standard based on culture methods takes up to 10 days to show positive results. For this reason, a flow-based chemiluminescence (CL) DNA microarray was developed that is able to quantify viable and non-viable Legionella spp. as well as Legionella pneumophila in one hour. An isothermal heterogeneous asymmetric recombinase polymerase amplification (haRPA) was carried out on flow-based CL DNA microarrays. Detection limits of 87 genomic units (GU) µL-1 and 26GUµL-1 for Legionella spp. and Legionella pneumophila, respectively, were achieved. In this work, it was shown for the first time that the combination of a propidium monoazide (PMA) treatment with haRPA, the so-called viability haRPA, is able to identify viable Legionella on DNA microarrays. Different proportions of viable and non-viable Legionella, shown with the example of L. pneumophila, ranging in a total concentration between 101 to 105GUµL-1 were analyzed on the microarray analysis platform MCR 3. Recovery values for viable Legionella spp. were found between 81% and 133%. With the combination of these two methods, there is a chance to replace culture-based methods in the future for the monitoring of engineered water systems like condensation recooling plants.
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Affiliation(s)
- Catharina Kober
- Institute of Hydrochemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Marchioninistrasse 17, 81377 München, Germany
| | - Reinhard Niessner
- Institute of Hydrochemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Marchioninistrasse 17, 81377 München, Germany
| | - Michael Seidel
- Institute of Hydrochemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Marchioninistrasse 17, 81377 München, Germany.
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Lim HJ, Choi JH, Son A. Necessity of purification during bacterial DNA extraction with environmental soils. ENVIRONMENTAL HEALTH AND TOXICOLOGY 2017; 32:e2017013. [PMID: 28793754 PMCID: PMC5704571 DOI: 10.5620/eht.e2017013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/08/2017] [Indexed: 05/31/2023]
Abstract
Complexity and heterogeneity of soil samples have often implied the inclusion of purification steps in conventional DNA extraction for polymerase chain reaction (PCR) assays. Unfortunately the purification steps are also time and labor intensive. Therefore the necessity of DNA purification was re-visited and investigated for a variety of environmental soil samples that contained various amounts of PCR inhibitors. Bead beating and centrifugation was used as the baseline (without purification) method for DNA extraction. Its performance was compared with that of conventional DNA extraction kit (with purification). The necessity criteria for DNA purification were established with environmental soil samples. Using lysis conditions at 3000 rpm for 3 minutes with 0.1 mm glass beads, centrifugation time of 10 minutes and 1:10 dilution ratio, the baseline method outperformed conventional DNA extraction on cell seeded sand samples. Further investigation with PCR inhibitors (i.e., humic acids, clay, and magnesium [Mg]) showed that sand samples containing less than 10 μg/g humic acids and 70% clay may not require purifications. Interestingly, the inhibition pattern of Mg ion was different from other inhibitors due to the complexation interaction of Mg ion with DNA fragments. It was concluded that DNA extraction method without purification is suitable for soil samples that have less than 10 μg/g of humic acids, less than 70% clay content and less than 0.01% Mg ion content.
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Affiliation(s)
| | | | - Ahjeong Son
- Correspondence: Ahjeong Son Department of Environmental Science and Engineering, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Korea E-mail:
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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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41
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Peter A, Thompson KC, Routledge EJ. Barriers to effectiveLegionellacontrol in a changing world: a practitioner’s view. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/21622515.2017.1335352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Aji Peter
- Institute of Environment, Health and Societies, Brunel University London, Uxbridge, UK
| | | | - Edwin John Routledge
- Institute of Environment, Health and Societies, Brunel University London, Uxbridge, UK
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42
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Polo-López MI, Castro-Alférez M, Nahim-Granados S, Malato S, Fernández-Ibáñez P. Legionella jordanis inactivation in water by solar driven processes: EMA-qPCR versus culture-based analyses for new mechanistic insights. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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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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44
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Bonetta S, Pignata C, Bonetta S, Meucci L, Giacosa D, Marino E, Gilli G, Carraro E. Viability of Legionella pneumophila in Water Samples: A Comparison of Propidium Monoazide (PMA) Treatment on Membrane Filters and in Liquid. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14050467. [PMID: 28448459 PMCID: PMC5451918 DOI: 10.3390/ijerph14050467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 11/16/2022]
Abstract
Legionella pneumophila is a ubiquitous microorganism widely distributed in aquatic environments and can cause Legionellosis in humans. A promising approach to detect viable cells in water samples involves the use of quantitative polymerase chain reaction (qPCR) in combination with photoactivatable DNA intercalator propidium monoazide (PMA). However, the PMA efficiency could be different depending on the experimental conditions used. The aim of this study was to compare two PMA exposure protocols: (A) directly on the membrane filter or (B) in liquid after filter washing. The overall PMA-induced qPCR means reductions in heat-killed L. pneumophila cells were 2.42 and 1.91 log units for exposure protocols A and B, respectively. A comparison between the results obtained reveals that filter exposure allows a higher PMA-qPCR signal reduction to be reached, mainly at low concentrations (p < 0.05). This confirms the potential use of this method to quantify L. pneumophila in water with low contamination.
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Affiliation(s)
- Sara Bonetta
- Department of Public Health and Pediatrics, University of Torino, P.zza Polonia 94, 10126 Torino, Italy.
| | - Cristina Pignata
- Department of Public Health and Pediatrics, University of Torino, P.zza Polonia 94, 10126 Torino, Italy.
| | - Silvia Bonetta
- Department of Public Health and Pediatrics, University of Torino, P.zza Polonia 94, 10126 Torino, Italy.
| | - Lorenza Meucci
- Società Metropolitana Acque Torino S.p.A., C.so XI Febbraio, 14, 10152 Torino, Italy.
| | - Donatella Giacosa
- Società Metropolitana Acque Torino S.p.A., C.so XI Febbraio, 14, 10152 Torino, Italy.
| | - Elena Marino
- Società Metropolitana Acque Torino S.p.A., C.so XI Febbraio, 14, 10152 Torino, Italy.
| | - Giorgio Gilli
- Department of Public Health and Pediatrics, University of Torino, P.zza Polonia 94, 10126 Torino, Italy.
| | - Elisabetta Carraro
- Department of Public Health and Pediatrics, University of Torino, P.zza Polonia 94, 10126 Torino, Italy.
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45
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Takahashi H, Gao Y, Miya S, Kuda T, Kimura B. Discrimination of live and dead cells of Escherichia coli using propidium monoazide after sodium dodecyl sulfate treatment. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.06.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Farzi N, Abrehdari-Tafreshi Z, Zarei O, Chamani-Tabriz L. Detection of Legionella Pneumophila in Urine and Serum Specimens of Neutropenic Febrile Patients with Haematological Malignancies. Int J Hematol Oncol Stem Cell Res 2017; 11:49-53. [PMID: 28286615 PMCID: PMC5338282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Background: Legionella pneumophila (L. pneumophila) is a gram-negative bacterium which causes Legionnaires' disease as well as Pontiac fever. The Legionella infections in patients suffering from neutropenia- as a common complication of cancer chemotherapy- can distribute rapidly. We aimed to detect of L. pneumophila in haematological malignancy suffering patients with neutropenic fever by targeting the (macrophage infectivity potentiator) mip gene. Subjects andMethods: Serum and urine specimens were obtained from 80 patients and presence of mip gene of L. pneumophila in specimens was investigated by PCR. Results: The L. pneumophila infection was detected in 21 (26.2%) and 38 (47.5%) of urine and serum specimens, respectively. Conclusion: Our findings indicated that the relative high prevalence of L. pneumophila in the studied patients group which show the necessity of considering this microorganism in future studies from detection and treatment point of view in cancer patients.
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Affiliation(s)
- Nastaran Farzi
- Department of Microbiology, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | | | - Omid Zarei
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leili Chamani-Tabriz
- Reproductive Biotechnology Research Center, Avicenna Research Institute (ACECR), Tehran, Iran
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47
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Lösch LS, Merino LA. [Presence of Legionella spp. in household drinking water reservoirs in Resistencia, Chaco, Argentina. Preliminary report]. Rev Argent Microbiol 2016; 48:329-332. [PMID: 28029443 DOI: 10.1016/j.ram.2016.07.002] [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: 04/04/2016] [Revised: 06/16/2016] [Accepted: 07/05/2016] [Indexed: 11/30/2022] Open
Abstract
Legionella spp. is an environmental bacterium that can survive in a wide range of physicochemical conditions and may colonize distribution systems of drinking water and storage tanks. Legionella pneumophila is the major waterborne pathogen that can cause 90% of Legionnaires' disease cases. The aim of this study was to detect the presence of Legionella spp. in household drinking water tanks in the city of Resistencia, Chaco. The detection of Legionella in water samples was performed by culture methods as set out in ISO 11731:1998. Thirty two water samples were analyzed and Legionella spp. was recovered in 12 (37.5%) of them. The monitoring of this microorganism in drinking water is the first step towards addressing the control of its spread to susceptible hosts.
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Affiliation(s)
- Liliana S Lösch
- Área de Bacteriología, Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina; Cátedra de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad Nacional del Nordeste, Corrientes, Argentina.
| | - Luis A Merino
- Área de Bacteriología, Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina; Cátedra de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad Nacional del Nordeste, Corrientes, Argentina
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48
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Whiley H. Legionella Risk Management and Control in Potable Water Systems: Argument for the Abolishment of Routine Testing. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 14:E12. [PMID: 28029126 PMCID: PMC5295263 DOI: 10.3390/ijerph14010012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 01/05/2023]
Abstract
Legionella is an opportunistic pathogen of public health significance. One of the main sources of Legionella is potable water systems. As a consequence of aging populations there is an increasing demographic considered at high risk for Legionellosis and, as such, a review of the guidelines is required. Worldwide, Legionella has been detected from many potable water sources, suggesting it is ubiquitous in this environment. Previous studies have identified the limitations of the current standard method for Legionella detection and the high possibility of it returning both false negative and false positive results. There is also huge variability in Legionella test results for the same water sample when conducted at different laboratories. However, many guidelines still recommend the testing of water systems. This commentary argues for the removal of routine Legionella monitoring from all water distribution guidelines. This procedure is financially consuming and false negatives may result in managers being over-confident with a system or a control mechanism. Instead, the presence of the pathogen should be assumed and focus spent on managing appropriate control measures and protecting high-risk population groups.
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Affiliation(s)
- Harriet Whiley
- Health and the Environment, School of the Environment, Flinders University, GPO Box 2100, Adelaide 5001, Australia.
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49
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Strauss A, Dobrowsky PH, Ndlovu T, Reyneke B, Khan W. Comparative analysis of solar pasteurization versus solar disinfection for the treatment of harvested rainwater. BMC Microbiol 2016; 16:289. [PMID: 27938342 PMCID: PMC5148859 DOI: 10.1186/s12866-016-0909-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/06/2016] [Indexed: 12/20/2022] Open
Abstract
Background Numerous pathogens and opportunistic pathogens have been detected in harvested rainwater. Developing countries, in particular, require time- and cost-effective treatment strategies to improve the quality of this water source. The primary aim of the current study was thus to compare solar pasteurization (SOPAS; 70 to 79 °C; 80 to 89 °C; and ≥90 °C) to solar disinfection (SODIS; 6 and 8 hrs) for their efficiency in reducing the level of microbial contamination in harvested rainwater. The chemical quality (anions and cations) of the SOPAS and SODIS treated and untreated rainwater samples were also monitored. Results While the anion concentrations in all the samples were within drinking water guidelines, the concentrations of lead (Pb) and nickel (Ni) exceeded the guidelines in all the SOPAS samples. Additionally, the iron (Fe) concentrations in both the SODIS 6 and 8 hr samples were above the drinking water guidelines. A >99% reduction in Escherichia coli and heterotrophic bacteria counts was then obtained in the SOPAS and SODIS samples. Ethidium monoazide bromide quantitative polymerase chain reaction (EMA-qPCR) analysis revealed a 94.70% reduction in viable Legionella copy numbers in the SOPAS samples, while SODIS after 6 and 8 hrs yielded a 50.60% and 75.22% decrease, respectively. Similarly, a 99.61% reduction in viable Pseudomonas copy numbers was observed after SOPAS treatment, while SODIS after 6 and 8 hrs yielded a 47.27% and 58.31% decrease, respectively. Conclusion While both the SOPAS and SODIS systems reduced the indicator counts to below the detection limit, EMA-qPCR analysis indicated that SOPAS treatment yielded a 2- and 3-log reduction in viable Legionella and Pseudomonas copy numbers, respectively. Additionally, SODIS after 8 hrs yielded a 2-log and 1-log reduction in Legionella and Pseudomonas copy numbers, respectively and could be considered as an alternative, cost-effective treatment method for harvested rainwater.
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Affiliation(s)
- André Strauss
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Penelope Heather Dobrowsky
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Thando Ndlovu
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Brandon Reyneke
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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50
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Ahmad F, Stedtfeld RD, Waseem H, Williams MR, Cupples AM, Tiedje JM, Hashsham SA. Most probable number - loop mediated isothermal amplification (MPN-LAMP) for quantifying waterborne pathogens in <25min. J Microbiol Methods 2016; 132:27-33. [PMID: 27856278 DOI: 10.1016/j.mimet.2016.11.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/12/2016] [Accepted: 11/12/2016] [Indexed: 01/20/2023]
Abstract
We are reporting a most probable number approach integrated to loop mediated isothermal technique (MPN-LAMP) focusing on Gram-negative Escherichia coli and Gram-positive Enterococcus faecalis bacterial cells without nucleic acids extraction. LAMP assays for uidA from E. coli and gelE from E. faecalis were successfully performed directly on cells up to single digit concentration using a commercial real time PCR instrument. Threshold time values of LAMP assays of bacterial cells, heat treated bacterial cells (95°C for 5min), and their purified genomic DNA templates were similar, implying that amplification could be achieved directly from bacterial cells at 63°C. Viability of bacterial cells was confirmed by using propidium monoazide in a LAMP assay with E. faecalis. To check its functionality on a microfluidic platform, MPN-LAMP assays targeting <10CFU of bacteria were also translated onto polymeric microchips and monitored by a low-cost fluorescence imaging system. The overall system provided signal-to-noise (SNR) ratios up to 800, analytical sensitivity of <10CFU, and time to positivity of about 20min. MPN-LAMP assays were performed for cell concentrations in the range of 105CFU to <10CFU. MPN values from LAMP assays confirmed that the amplifications were from <10CFU. The method described here, applicable directly on cells at 63°C, eliminates the requirement of complex nucleic acids extraction steps, facilitating the development of sensitive, rapid, low-cost, and field-deployable systems. This rapid MPN-LAMP approach has the potential to replace conventional MPN method for waterborne pathogens.
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Affiliation(s)
- Farhan Ahmad
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Robert D Stedtfeld
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Hassan Waseem
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Maggie R Williams
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Alison M Cupples
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - James M Tiedje
- The Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Syed A Hashsham
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA; The Center for Microbial Ecology, Michigan State University, East Lansing, MI 48824, USA.
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