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Hayatimehr S, Mirkalantari S, Amirmozafari N, Jazi FM, Moghadam MT. Virulence Genes and Biofilm Formation Among Legionella pneumophila Isolates Collected from Hospital Water Sources. Curr Microbiol 2024; 81:141. [PMID: 38625380 DOI: 10.1007/s00284-023-03609-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/29/2023] [Indexed: 04/17/2024]
Abstract
Legionella pneumophila can be transmitted to people, especially immunocompromised patients, via hospital water pipe systems and cause severe pneumonia. The aim of our study was to investigate the presence of major virulence factor genes, ability of biofilms formation, and correlation between presence of Legionella isolates and temperature, pH, and residual chlorine of water. Hundred water samples were collected from nine hospitals in Tehran, Iran. Temperature, pH, and residual chlorine were determined during sampling. Different virulence genes and the ability to form biofilms were subsequently analyzed among the L. pneumophila isolates. Results showed that 12 (12%) samples were positive in culture method and all of the isolates were positive as L. pneumophila species (mip). A correlation was found between Legionella culture positivity and temperature and pH of water, but there was no significant correlation between residual chlorine of water samples and the presence of Legionella. The isolation of Legionella rate in summer and spring was higher than winter and autumn. Twelve (100%) isolates were positive for mip genes, 9 (75%) for dot genes, 8 (66.66%) for hsp, 6 (50%) for lvh, and 4 (33.33%) for rtx. All of the isolates displayed strong ability for biofilm production every three days. Two of these isolates (16.6%) displayed weak ability to form biofilm on the first day of incubation. This study revealed that water sources in hospitals were colonized by virulent Legionella and should be continuously monitored to avoid elevated concentrations of Legionella with visible biofilm formation.
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Affiliation(s)
- Sara Hayatimehr
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Shiva Mirkalantari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Nour Amirmozafari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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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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Gleason JA, Newby R, Gaynor JJ, Lee LH, Chu T, Bliese AD, Taylor CW, Yoon P, DeLorenzo S, Pranitis D, Bella J. Legionella monitoring results by water quality characteristics in a large public water system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:55974-55988. [PMID: 36913019 DOI: 10.1007/s11356-023-26198-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
Legionella, the causative agent of Legionnaires' disease, is an emerging concern for water utilities. Passaic Valley Water Commission (PVWC) is a public drinking water supplier, which provides treated surface water to approximately 800,000 customers in New Jersey. To evaluate the occurrence of Legionella in the PVWC distribution system, swab, first draw, and flushed cold water samples were collected from total coliform sites (n = 58) during a summer and winter sampling event. Endpoint PCR detection methods were combined with culture for Legionella detection. Among 58 total coliform sites during the summer, 17.2% (10/58) of first draw samples were positive for 16S and mip Legionella DNA markers and 15.5% (9/58) in flushed samples. Across both summer and winter sampling, a total of four out of 58 sites had low-level culture detection of Legionella spp. (0.5-1.6 CFU/mL) among first draw samples. Only one site had both a first and flush draw detection (8.5 CFU/mL and 1.1 CFU/mL) for an estimated culture detection frequency of 0% in the summer and 1.7% in the winter among flushed draw samples. No L. pneumophila was detected by culture. Legionella DNA detection was significantly greater in the summer than in the winter, and detection was greater in samples collected from areas treated with phosphate. No statistical difference was found between first draw and flush sample detection. Total organic carbon, copper, and nitrate were significantly associated with Legionella DNA detection.
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Affiliation(s)
- Jessie A Gleason
- Environmental and Occupational Health Surveillance Program, New Jersey Department of Health, 135 East State Street, P.O. Box 369, Trenton, NJ, 08625, USA.
| | - Robert Newby
- Division of Science, New Jersey Department of Environmental Protection, 428 East State Street, P.O. Box 420, Trenton, NJ, 08625, USA
| | - John J Gaynor
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Lee H Lee
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Tinchun Chu
- Department of Biological Sciences, Seton Hall University, 400 South Orange Ave, South Orange, NJ, 07076, USA
| | - Alorah D Bliese
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Calvin W Taylor
- Department of Biology, Montclair State University, Montclair, NJ, 07043, USA
| | - Paul Yoon
- Department of Biological Sciences, Seton Hall University, 400 South Orange Ave, South Orange, NJ, 07076, USA
| | - Suzanne DeLorenzo
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
| | - David Pranitis
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
| | - Joe Bella
- Passaic Valley Water Commission, 1525 Main Avenue, Totowa, NJ, 07512, USA
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Evaluation of a Natural Phytogenic Formulation as an Alternative to Pharmaceutical Zinc Oxide in the Diet of Weaned Piglets. Animals (Basel) 2023; 13:ani13030431. [PMID: 36766320 PMCID: PMC9913353 DOI: 10.3390/ani13030431] [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: 12/02/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/03/2023] Open
Abstract
A natural phytogenic formulation (NPF) was tested as an alternative to pharmaceutical zinc oxide (ZnO) in weaned piglets with respect to growth performance, apparent total tract digestibility and faecal microbiota composition and metabolic activity. Two dietary NPF levels (NPF: 1000 and 2000 mg/kg diet) were compared to a positive control (ZnO: 3000 mg ZnO/kg diet) and a negative control (CON: no added ZnO or NPF) using 84 weaned piglets from 29 d to 78 d (days of age). Feed conversion ratio was improved (p < 0.05) in ZnO and NPF piglets were compared to CON at 50 d. Dry matter, organic matter and crude protein (p < 0.05) digestibility was improved in NPF piglets compared to CON at 57 d. Compared to CON, NPF inclusion reduced E. coli (p < 0.05) and increased C. leptum subgroup (p < 0.01) at 57 d and 78 d, and reduced C. perfringens subgroup (p < 0.05; at 78 d). The ZnO reduced (p < 0.001) E. coli and C. perfringens subgroup (p < 0.01) compared to CON at 78 d. Moreover, ZnO and NPF reduced molar ratios of branched chain volatile fatty acids (p < 0.05) compared to CON, while NPF also increased butyric acid (p < 0.05) at 78 d. In conclusion, the NPF appeared to be a promising alternative to pharmaceutical doses of ZnO.
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Clinical and Laboratory Diagnosis of Legionella Pneumonia. Diagnostics (Basel) 2023; 13:diagnostics13020280. [PMID: 36673091 PMCID: PMC9858276 DOI: 10.3390/diagnostics13020280] [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: 11/29/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Legionella pneumonia is a relatively rare but extremely progressive pulmonary infection with high mortality. Traditional cultural isolation remains the gold standard for the diagnosis of Legionella pneumonia. However, its harsh culture conditions, long turnaround time, and suboptimal sensitivity do not meet the clinical need for rapid and accurate diagnosis, especially for critically ill patients. So far, pathogenic detection techniques including serological assays, urinary antigen tests, and mass spectrometry, as well as nucleic acid amplification technique, have been developed, and each has its own advantages and limitations. This review summarizes the clinical characteristics and imaging findings of Legionella pneumonia, then discusses the advances, advantages, and limitations of the various pathogenetic detection techniques used for Legionella pneumonia diagnosis. The aim is to provide rapid and accurate guiding options for early identification and diagnosis of Legionella pneumonia in clinical practice, further easing healthcare burden.
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Palamidi I, Paraskeuas VV, Mountzouris KC. Dietary and phytogenic inclusion effects on the broiler chicken cecal ecosystem. FRONTIERS IN ANIMAL SCIENCE 2023. [DOI: 10.3389/fanim.2022.1094314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Dietary modulation in broilers is crucial for the establishment of beneficial microbiota and, subsequently, the promotion of intestinal health. In this trial, a 2 × 2 factorial design was used with two different specifications with respect to dietary metabolizable energy (ME) and crude protein (CP) levels (i.e., 95% and 100% of recommendations) and phytogenic levels (0 and 150 mg/kg). Levels of total bacteria, Bacteroides spp., Lactobacillus spp., and Clostridium cluster XIVa attached to the cecal mucosa and in the cecal digesta were lower in broilers fed the 95% ME and CP specification diets, as was the molar ratio of butyric acid. In addition, the relative activity of autoinducers-2 (AI-2) and the expression levels of TLR4 and AvBD6 were increased. Phytogenic supplementation reduced cecal digesta levels of Escherichia coli and Clostridium cluster I levels, and increased Clostridium cluster IV levels. Moreover, the butyric acid molar ratio and the relative activity of AI-2 were increased, whereas the concentration of branched VFAs and the expression of AvBD6 and LEAP2 were reduced by phytogenic administration. Dietary specifications and phytogenic interactions were shown for the cecal-attached microbiota composition, metabolic activity of digesta microbiota, relative expression of autoinducers-2, and relative expression of toll-like signaling molecules and host antimicrobial peptides. In conclusion, it has been shown that ME and CP dietary specifications, combined or not with phytogenics, modulate multilevel gut biomarkers ranging from microbiota composition and metabolic activity to microbial communications and host signaling, inflammation, and defense.
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Karimiravesh R, Mohabati Mobarez A, Behmanesh M, Nikkhah M, Talebi Bezmin Abadi A, Esmaeilli S. Design of an optical nanobiosensor for detection of Legionella pneumophila in water samples. IRANIAN JOURNAL OF MICROBIOLOGY 2022; 14:802-812. [PMID: 36721447 PMCID: PMC9867621 DOI: 10.18502/ijm.v14i6.11254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background and Objectives Legionella spp. is a causative agent of Legionnaires' disease that creates public health problems. Isolation of these bacteria from water sources is essential to identify outbreak origins and prevent disease. Diagnostic biosensors for water quality control to protect consumers from water-borne infections can predict many outbreaks. Gold nanoparticles conjugated probes are a new generation of diagnostic tools. In this study, an optical nano biosensor was designed and characterized to detect Legionella pneumophila in water samples rapidly. Materials and Methods Thiolated probes designed for the mip gene were attached to gold nanoparticles and then water samples containing Legionella pneumophila were examined. Results The limit of detection for PCR and biosensor was 104 and 103 copy numbers/μl, respectively. Biosensor sensitivity and PCR were reported to be 90% (18 out of 20) and 85% (17 out of 20), respectively. Specificity 100% has been reported for both methods. Conclusion According to the obtained results, this method has the potential to diagnose L. pneumophila with high sensitivity and specificity. This system can be employed as a practical tool for rapid, accurate, high-sensitivity, and acceptable detection of Legionella pneumophila in contaminated water, which is cost-effective in terms of cost and time.
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Affiliation(s)
- Raheleh Karimiravesh
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ashraf Mohabati Mobarez
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran,Corresponding author: Ashraf Mohabati Mobarez, Ph.D, Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Tel: +98-21-82883862 Fax: +98-21-82884555
| | - Mehrdad Behmanesh
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Nikkhah
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amin Talebi Bezmin Abadi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saber Esmaeilli
- National Reference Laboratory for Plague, Tularemia and Q fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Akanlu, Kabudar Ahang, Hamadan, Iran,Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
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Consonni M, Grassi A, Scuri S, Gori M, Tanzi E, Tesauro M. Assessing the viability of Legionella pneumophila in environmental samples: regarding the filter application of Ethidium Monoazide Bromide. ANN MICROBIOL 2021. [DOI: 10.1186/s13213-021-01653-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Purpose
Analyses of 34 water samples from 13 healthcare structures revealed how culture method and quantitative PCR (qPCR) often differ in the detection of Legionella pneumophila (Lp). With these considerations in hand, culture method, PCR and Ethidium Monoazide Bromide (EMA) qPCR have all been compared in order to detect Lp in water samples, identify a method able to speed up the procedures, detect the “viable but not cultivable” bacteria (VBNC) and exclude non-viable bacteria using a commercial kit for extraction and amplification as well as modification of the protocol.
Methods
Pure water samples artificially spiked with viable, non-viable and VBNC Lp ATCC 33152 were analyzed using a commercial kit for both qPCR and EMA-qPCR, while ISO 11731-2-2004 was used for culture method.
Results
Only 35% (12/34) of the environmental samples were positive in both culture and qPCR methods. With regard to EMA-qPCR, results showed the absence of dye toxicity on viable and VBNC strains and an incomplete effectiveness on the non-viable ones. In both viable and VBNC strains, a decrease of bacterial DNA amplification was recorded as a function of sample dilution but not of EMA concentration.
Conclusions
Discrepancies between culture method and EMA-qPCR were observed and may be due to different causes such as membrane-dye interactions, presence of interfering compounds and the sensitivity of the kit used.
Study significance and impact
In the presence of one or more suspected cases of nosocomial legionellosis, the application of a rapid molecular method able to identify only the viable and VBNC Lp would be useful in order to quickly identify the source of infection and to intervene with sanitation treatments. However, seeing that in our experience EMA pretreatment on the filter membrane did not come up with the expected results, it would be necessary to proceed with other experiments and/or different dyes.
Graphical Abstract
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Martinelli M, Calaresu E, Musumeci R, Giubbi C, Perdoni F, Frugoni S, Castriciano S, Scaturro M, Ricci ML, Cocuzza CE. Evaluation of an Environmental Transport Medium for Legionella pneumophila Recovery. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18168551. [PMID: 34444305 PMCID: PMC8394066 DOI: 10.3390/ijerph18168551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 11/16/2022]
Abstract
The collection and storage of water-related matrices such as biofilm from collection to processing are critical for the detection of Legionella pneumophila by cultural and molecular tests. SRK™ is a liquid medium that acts both as an antimicrobial neutralizing agent and a transport medium for bacterial culture enumeration and is useful to maintain the stability of the sample from collection to analysis. The aims of this study were to evaluate Legionella pneumophila viability and bacterial nucleic acids’ stability in SRK™ medium over time at different storage conditions. Artificial bacterial inoculates with an approximate concentration of 104, 103 and 102 CFU/mL were made using Legionella pneumophila certified reference material suspended in SRK™ medium. Bacteria recovery was analyzed by cultural and molecular methods at time 0, 24 and 48 h at room temperature and at 0, 24, 48 and 72 h at 2–8 °C, respectively. SRK™ medium supported Legionella pneumophila culture viability with CFU counts within the expected range. The recovery after 72 h at 2–8 °C was 83–100% and 75–95% after 48 h at room temperature. Real-time PCR appropriately detected Legionella pneumophila DNA at each temperature condition, dilution and time point. Results demonstrated a good performance of SRK™ medium for the reliable recovery of environmental Legionella.
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Affiliation(s)
- Marianna Martinelli
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
- Correspondence: ; Tel.: +39-02-6448-8359
| | - Enrico Calaresu
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
| | - Rosario Musumeci
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
| | - Chiara Giubbi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
| | - Federica Perdoni
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
| | - Sergio Frugoni
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
| | | | - Maria Scaturro
- Istituto Superiore di Sanità, 00161 Roma, Italy; (M.S.); (M.L.R.)
| | | | - Clementina E. Cocuzza
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.C.); (R.M.); (C.G.); (F.P.); (S.F.); (C.E.C.)
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Donohue MJ. Quantification of Legionella pneumophila by qPCR and culture in tap water with different concentrations of residual disinfectants and heterotrophic bacteria. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 774:145142. [PMID: 33610980 PMCID: PMC8358786 DOI: 10.1016/j.scitotenv.2021.145142] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 05/21/2023]
Abstract
Legionellosis prevalence is increasing in the United States. This disease is caused primarily by the bacterium Legionella pneumophila found in water and transmitted by aerosol inhalation. This pathogen has a slow growth rate and can "hide" in amoeba, making it difficult to monitor by the traditional culture method on selective media. Tap water samples (n = 358) collected across the United States were tested for L. pneumophila by both culture and quantitative Polymerase Chain Reaction (qPCR). The presence of other bacteria was quantified by heterotrophic plate counts (HPC). Residual disinfectant concentrations (free chlorine or monochloramine) were measured in all samples. Legionella pneumophila had the highest prevalence and concentration in the chlorinated water samples that had a free‑chlorine value of less than 0.2 mg Cl2/L. In total, 24% (87/358) of the samples were positive for L. pneumophila either by qPCR or 3% (11/358) were positive by culture. In chloramine-treated samples, L. pneumophila was detected by qPCR in 21% (31/148) and 1% (2/148) by culture, despite a high monochloramine residual >1 mg Cl2/L. Despite the presence of a high disinfectant residual (>1 mg Cl2/L), HPC counts were substantial. This study indicates that both culture and qPCR methods have limitations when predicting a potential risk for disease associated with L. pneumophila in tap water. Measuring disinfectant residuals and quantifying HPC in water samples may be useful adjunct parameters for reducing Legionellosis' risk from public water supplies at high-risk locations.
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Affiliation(s)
- Maura J Donohue
- United States Environmental Protection Agency, Office Research and Development, Center for Environmental Solutions and Emergency Response, Cincinnati, OH 45268, United States of America.
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Duquette-Lozeau K, Létourneau V, Lemieux J, Fournel S, Côté C, Godbout S, Duchaine C. Production of composted recycled manure solids from a Canadian dairy farm: Impact on microbial air quality in experimental conditions. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2021; 71:413-421. [PMID: 33030410 DOI: 10.1080/10962247.2020.1832620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
Recycled manure solids (RMS) produced in dairy farms from fresh manure need to be sanitized before using them as bedding material. However, the impact on air quality of composting RMS remains unknown. Four RMS composting methods were tested during a 10-day aging of piles in experimental chambers: static windrow (SW), turned windrow (TW), SW following drum composting for 24 h (DC24) or SW following drum composting for 72 h (DC72). Air samples were collected using a SASS®3100 Dry Air Sampler on days 0 (pilling of the RMS), 5, and 10. Bacteria (16S rRNA genes), Penicillium/Aspergillus, A fumigatus, and 11 human pathogenic bacteria (e.g. Klebsiella pneumonia) were quantified by qPCR while endotoxins and dust particles were, respectively, measured by LAL assays and with a DustTrakTM DRX Aerosol Monitor. On day 0, RMS produced by SW and TW yielded the lowest concentrations of airborne bacteria, while DC24 resulted in the lowest levels of Penicillium/Aspergillus and dust particles. SW method led on day 5 to the lowest concentration of bacteria and Penicillium/Aspergillus, and DC24 and DC72 to the lowest concentration of airborne dust. On day 10, SW and TW piles were associated with the lowest levels of Penicillium/Aspergillus and dust particles. A significant difference was observed between concentration of airborne bacteria, Penicillium/Aspergillus and endotoxins before and during the turnover of TW piles. None of the studied human pathogens was detected in the air samples. Results of the present study suggest that SW and TW are the most promising methods for the production of composted RMS with respect to microbial air quality. However, the experimental chambers do not accurately represent commercial dairy barns and further research on these composting methods is necessary. Finally, the study highlights that bedding material and its management may be determinant factors for air quality in dairy barns.Implications: The research evaluated the impact on microbial air quality of composting recycled manure solids (RMS) produced from fresh cow manure. RMS need to be composted or sanitized before using them as bedding material for animals. The impact on animal health of RMS still needs to be confirmed, while the effect on air quality and the health of dairy farmers is unknown. In the present study, microbial air quality associated with four RMS composting methods was investigated. Data revealed that two methods resulted in lower aerosolization of dust particles, endotoxins, molds, and bacteria.
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Affiliation(s)
- Karine Duquette-Lozeau
- Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Canada
| | - Valérie Létourneau
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada
| | - Joanie Lemieux
- Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Canada
| | - Sébastien Fournel
- Département des sols et de génie agroalimentaire, Université Laval, Québec, Canada
| | - Caroline Côté
- Research and Development Institute for the Agri-Environment (IRDA), Québec, Canada
| | - Stéphane Godbout
- Research and Development Institute for the Agri-Environment (IRDA), Québec, Canada
| | - Caroline Duchaine
- Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Canada
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada
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12
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Young C, Smith D, Wafer T, Crook B. Rapid Testing and Interventions to Control Legionella Proliferation following a Legionnaires' Disease Outbreak Associated with Cooling Towers. Microorganisms 2021; 9:microorganisms9030615. [PMID: 33802700 PMCID: PMC8002549 DOI: 10.3390/microorganisms9030615] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/04/2021] [Accepted: 03/13/2021] [Indexed: 11/16/2022] Open
Abstract
Most literature to date on the use of rapid Legionella tests have compared different sampling and analytical techniques, with few studies on real-world experiences using such methods. Rapid tests offer a significantly shorter feedback loop on the effectiveness of the controls. This study involved a complex of five factories, three of which had a history of Legionella contamination in their cooling water distribution system. Multiple sampling locations were utilised to take monthly water samples over 39 months to analyse for Legionella by both culture and quantitative polymerase chain reaction (qPCR). Routine monitoring gave no positive Legionella results by culture (n = 330); however, samples were frequently (68%) positive by qPCR for Legionella spp. (n = 1564). Legionella spp. qPCR assay was thus found to be a good indicator of cooling tower system health and suitable as a routine monitoring tool. An in-house qPCR limit of 5000 genomic units (GU)/L Legionella spp. was established to trigger investigation and remedial action. This approach facilitated swift remedial action to prevent Legionella proliferation to levels that may represent a public health risk. Cooling tower operators may have to set their own action levels for their own systems; however, in this study, 5000 GU/L was deemed appropriate and pragmatic.
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Affiliation(s)
| | - Duncan Smith
- Health and Safety Executive, Newcastle NE98 1YX, UK;
| | - Tim Wafer
- Water Solutions Group, Harrogate HG3 1EQ, UK;
| | - Brian Crook
- Health and Safety Executive, Buxton SK17 9JN, UK;
- Correspondence: ; Tel.: +44-203-028-1882
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13
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Buse HY, Morris BJ, Gomez-Alvarez V, Szabo JG, Hall JS. Legionella Diversity and Spatiotemporal Variation in The Occurrence of Opportunistic Pathogens within a Large Building Water System. Pathogens 2020; 9:E567. [PMID: 32668779 PMCID: PMC7400177 DOI: 10.3390/pathogens9070567] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/22/2023] Open
Abstract
Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occurrence within a BWS over 18-28 months at six locations differing in plumbing material and potable water age, quality, and usage. A total of 114 bulk water and 57 biofilm samples were analyzed. Legionella culturability fluctuated seasonally with most culture-positive samples being collected during the winter compared to the spring, summer, and fall months. Positive and negative correlations between Legionella and L. pneumophila occurrence and other physiochemical and microbial water quality parameters varied between location and sample types. Whole genome sequencing of 19 presumptive Legionella isolates, from four locations across three time points, identified nine isolates as L. pneumophila serogroup (sg) 1 sequence-type (ST) 1; three as L. pneumophila sg5 ST1950 and ST2037; six as L. feeleii; and one as Ochrobactrum. Results showed the presence of a diverse Legionella population with consistent and sporadic occurrence at four and two locations, respectively. Viewed collectively with similar studies, this information will enable a better understanding of the engineering, operational, and water quality parameters supporting Legionella growth within BWSs.
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Affiliation(s)
- Helen Y. Buse
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - Brian J. Morris
- Pegasus Technical Services, Inc c/o US EPA, Cincinnati, OH 45268, USA;
| | - Vicente Gomez-Alvarez
- Water Infrastructure Division, Center for Environmental Solutions & Emergency Response (CESER), US Environmental Protection Agency (USEPA), Office of Research and Development (ORD), Cincinnati, OH 45268, USA;
| | - Jeffrey G. Szabo
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - John S. Hall
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
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14
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Olabarria G, Eletxigerra U, Rodriguez I, Bilbao A, Berganza J, Merino S. Highly sensitive and fast Legionella spp. in situ detection based on a loop mediated isothermal amplification technique combined to an electrochemical transduction system. Talanta 2020; 217:121061. [PMID: 32498831 DOI: 10.1016/j.talanta.2020.121061] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/25/2022]
Abstract
A rapid highly sensitive genosensor has been developed for monitoring the presence of Legionella spp. in different water systems (domestic hot water, heating/cooling systems or cooling towers) in order to avoid its spreading from the source of contamination. The genosensor integrates a loop mediated isothermal amplification (LAMP) reaction with an electrochemical transduction signal, producing a very simple, rapid to perform and cost effective method, suitable for in situ analyses. This approach detects as low as 10 fg of Legionella nucleic acid, corresponding to only 2 number copies of the bacteria. The use of an electrochemical redox-active double stranded DNA (dsDNA) intercalating molecule, known as methylen blue (MB), allows the immediate electrochemical reading during the DNA polymerization. The sensor can obtain quantitative results in 20 min with a correlation between the electrochemical data and Legionella spp. copy number (at a logarithmic scale) of r = -0.97. In conclusion, a fast, easy to use, and accurate electrochemical genosensor, with high precision, sensitivity, and specificity has been developed for in situ detection of Legionella spp. enabling real time decision making and improving significantly the current detection methods for the prevention and screening of Legionella.
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Affiliation(s)
- Garbiñe Olabarria
- GAIKER Technology Centre, Basque Research and Technology Alliance (BRTA). Parque Tecnológico, Edificio 202. 48170, Zamudio, Spain.
| | - Unai Eletxigerra
- Surface Chemistry and Nanotechnologies Unit, Tekniker, Eibar, 20600, Spain
| | - Isabel Rodriguez
- GAIKER Technology Centre, Basque Research and Technology Alliance (BRTA). Parque Tecnológico, Edificio 202. 48170, Zamudio, Spain
| | - Ainhoa Bilbao
- GAIKER Technology Centre, Basque Research and Technology Alliance (BRTA). Parque Tecnológico, Edificio 202. 48170, Zamudio, Spain
| | - Jesus Berganza
- GAIKER Technology Centre, Basque Research and Technology Alliance (BRTA). Parque Tecnológico, Edificio 202. 48170, Zamudio, Spain
| | - Santos Merino
- Surface Chemistry and Nanotechnologies Unit, Tekniker, Eibar, 20600, Spain; Departamento de Electricidad y Electrónica, Universidad Del País Vasco UPV/EHU, 48940, Leioa, Spain
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15
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Mountzouris KC, Palamidi I, Paraskeuas V, Griela E, Fegeros K. Dietary probiotic form modulates broiler gut microbiota indices and expression of gut barrier genes including essential components for gut homeostasis. J Anim Physiol Anim Nutr (Berl) 2019; 103:1143-1159. [PMID: 31087706 DOI: 10.1111/jpn.13112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 12/28/2022]
Abstract
The probiotic form (PF) type and its dietary administration in combination or not with avilamycin (AV) were investigated for their effects on broiler gut microbiota and expression of genes relevant for gut barrier and gut homeostasis. Depending on PF type (i.e. no addition, viable, inactivated) and AV addition (no/yes), 450 one-day-old Cobb male broilers were allocated in 6 treatments (CON, CON + A, ViP, ViP + A, InP and InP + A) according to a 3 × 2 factorial arrangement with 5 replicates of 15 broilers each for 42 days. Significant interactions (PPF × AV ≤ 0.05) between PF and AV administration were shown for the ileal mucosa-associated bacteria, the caecal digesta Lactobacillus spp., the molar ratio of the sum of valeric, hexanoic and heptanoic acids and the gene expressions of ileal and caecal IgA and ileal claudin 1. Avilamycin suppressed ileal digesta Lactobacillus spp. (PAV < 0.001) and caecal digesta Clostridium perfringens subgroup (PAV = 0.018) and modulated the intestinal fermentation intensity and pattern. The viable PF had the higher levels of ileal digesta Bacteroides spp. (PPF = 0.021) and caecal digesta Lactobacillus spp. (PPF = 0.038) compared with the other two PF. Probiotic form modulated the microbial metabolic activity in the ileum and caeca with the viable PF being the most noteworthy in terms of effects regarded as beneficial. Furthermore, the viable PF resulted in reduced expression of caecal Toll-like receptors TLR2B (PPF = 0.026) and TLR4 (PPF = 0.011) and transcription factor NFΚΒ1 (PPF = 0.002), which could be considered as essential for limiting inflammation and preserving gut homeostasis. In conclusion, under non-challenge conditions, probiotic function was shown to depend on PF type and to a lesser degree on co-administration with AV. The importance of probiotic viability for the beneficial modulation of important gut components towards a reduced state of physiological inflammation has been highlighted.
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Affiliation(s)
| | - Irida Palamidi
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Athens, Greece
| | - Vasileios Paraskeuas
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Athens, Greece
| | - Eirini Griela
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Athens, Greece
| | - Konstantinos Fegeros
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Athens, Greece
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16
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Perrin Y, Bouchon D, Héchard Y, Moulin L. Spatio-temporal survey of opportunistic premise plumbing pathogens in the Paris drinking water distribution system. Int J Hyg Environ Health 2019; 222:687-694. [PMID: 31085113 DOI: 10.1016/j.ijheh.2019.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/07/2019] [Accepted: 04/19/2019] [Indexed: 11/26/2022]
Abstract
Opportunistic premise plumbing pathogens present in drinking water are linked to a significant number of infections for health compromised patients. However, their monitoring is not required in current water potability standards and they have been poorly studied in a full-scale network. In this study, we quantified, by qPCR, three opportunistic pathogens, Mycobacterium spp., Legionella pneumophila, Pseudomonas aeruginosa throughout the Paris drinking water network over a one-year sampling campaign. While Mycobacteria spp. seemed ubiquitous whatever the distribution system and the time of the year, the occurrence of L. pneumophila and P. aeruginosa showed seasonal variations. Unlike L. pneumophila and P. aeruginosa, the concentration (copies number/L) of Mycobacterium spp. varied between sampling sites. The variation in microbial numbers did not demonstrate any correlations with temperature, pH, chlorine, conductivity, orthophosphate or nitrate levels. In conclusion, Mycobacterium spp. are common inhabitants of the Paris network while L. pneumophila and P. aeruginosa presence fluctuate over space and time. Such qPCR approach would help to better understand the behaviour of opportunistic premise plumbing pathogens.
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Affiliation(s)
- Yoann Perrin
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France; Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, F-94200, Ivry sur Seine, France
| | - Didier Bouchon
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France
| | - Yann Héchard
- Laboratoire Ecologie et Biologie des Interactions, Equipes « Microbiologie de l'Eau » et « Ecologie, Evolution, Symbiose », Université de Poitiers, UMR CNRS 7267, F8 86073, Poitiers, France.
| | - Laurent Moulin
- Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, F-94200, Ivry sur Seine, France.
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17
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Long-term persistence of infectious Legionella with free-living amoebae in drinking water biofilms. Int J Hyg Environ Health 2019; 222:678-686. [PMID: 31036480 DOI: 10.1016/j.ijheh.2019.04.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 04/03/2019] [Accepted: 04/18/2019] [Indexed: 11/23/2022]
Abstract
Prolific growth of pathogenic Legionella pneumophila within engineered water systems and premise plumbing, and human exposure to aerosols containing this bacterium results in the leading health burden of any water-related pathogen in developed regions. Ecologically, free-living amoebae (FLA) are an important group of the microbial community that influence biofilm bacterial diversity in the piped-water environment. Using fluorescent microscopy, we studied in-situ the colonization of L. pneumophila in the presence of two water-related FLA species, Willaertia magna and Acanthamoeba polyphaga in drinking water biofilms. During water flow as well as after periods of long-stagnation, the attachment and colonization of L. pneumophila to predeveloped water-biofilm was limited. Furthermore, W. magna and A. polyphaga showed no immediate interactions with L. pneumophila when introduced to the same natural biofilm environment. A. polyphaga encysted within 5-7 d after introduction to the tap-water biofilms and mostly persisted in cysts till the end of the study period (850 d). W. magna trophozoites, however, exhibited a time delay in feeding on Legionella and were observed with internalized L. pneumophila cells after 3 weeks from their introduction to the end of the study period and supported putative (yet limited) intracellular growth. The culturable L.pneumophila in the bulk water was reduced by 2-log over 2 years at room temperature but increased (without a change in mip gene copies by qPCR) when the temperature was elevated to 40 °C within the same closed-loop tap-water system without the addition of nutrients or fresh water. The overall results suggest that L. pneumophila maintains an ecological balance with FLA within the biofilm environment, and higher temperature improve the viability of L. pneumophila cells, and intracellular growth of Legionella is possibly cell-concentration dependent. Observing the preferential feeding behavior, we hypothesize that an initial increase of FLA numbers through feeding on a range of other available bacteria could lead to an enrichment of L. pneumophila, and later force predation of Legionella by the amoeba trophozoites results in rapid intracellular replication, leading to problematic concentration of L. pneumophila in water. In order to find sustainable control options for legionellae and various other saprozoic, amoeba-resisting bacterial pathogens, this work emphasizes the need for better understanding of the FLA feeding behavior and the range of ecological interactions impacting microbial population dynamics within engineered water systems.
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18
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Hamilton KA, Hamilton MT, Johnson W, Jjemba P, Bukhari Z, LeChevallier M, Haas CN, Gurian PL. Risk-Based Critical Concentrations of Legionella pneumophila for Indoor Residential Water Uses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4528-4541. [PMID: 30629886 DOI: 10.1021/acs.est.8b03000] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Legionella spp. is a key contributor to the United States waterborne disease burden. Despite potentially widespread exposure, human disease is relatively uncommon, except under circumstances where pathogen concentrations are high, host immunity is low, or exposure to small-diameter aerosols occurs. Water quality guidance values for Legionella are available for building managers but are generally not based on technical criteria. To address this gap, a quantitative microbial risk assessment (QMRA) was conducted using target risk values in order to calculate corresponding critical concentrations on a per-fixture and aggregate (multiple fixture exposure) basis. Showers were the driving indoor exposure risk compared to sinks and toilets. Critical concentrations depended on the dose response model (infection vs clinical severity infection, CSI), risk target used (infection risk vs disability adjusted life years [DALY] on a per-exposure or annual basis), and fixture type (conventional vs water efficient or "green"). Median critical concentrations based on exposure to a combination of toilet, faucet, and shower aerosols ranged from ∼10-2 to ∼100 CFU per L and ∼101 to ∼103 CFU per L for infection and CSI dose response models, respectively. As infection model results for critical L. pneumophila concentrations were often below a feasible detection limit for culture-based assays, the use of CSI model results for nonhealthcare water systems with a 10-6 DALY pppy target (the more conservative target) would result in an estimate of 12.3 CFU per L (arithmetic mean of samples across multiple fixtures and/or over time). Single sample critical concentrations with a per-exposure-corrected DALY target at each conventional fixture would be 1.06 × 103 CFU per L (faucets), 8.84 × 103 CFU per L (toilets), and 14.4 CFU per L (showers). Using a 10-4 annual infection risk target would give a 1.20 × 103 CFU per L mean for multiple fixtures and single sample critical concentrations of 1.02 × 105, 8.59 × 105, and 1.40 × 103 CFU per L for faucets, toilets, and showers, respectively. Annual infection risk-based target estimates are in line with most current guidance documents of less than 1000 CFU per L, while DALY-based guidance suggests lower critical concentrations might be warranted in some cases. Furthermore, approximately <10 CFU per mL L. pneumophila may be appropriate for healthcare or susceptible population settings. This analysis underscores the importance of the choice of risk target as well as sampling program considerations when choosing the most appropriate critical concentration for use in public health guidance.
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Affiliation(s)
- Kerry A Hamilton
- School for Sustainable Engineering and the Built Environment , Arizona State University , Tempe , Arizona 85281 , United States
- The Biodesign Institute Center for Environmental Health Engineering , Arizona State University , Tempe , Arizona 85281 , United States
| | - Mark T Hamilton
- Microsoft Applied Artificial Intelligence Group , 1 Memorial Drive , Cambridge , Massachusetts 02142 , United States
| | - William Johnson
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Patrick Jjemba
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Zia Bukhari
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Mark LeChevallier
- American Water Research Laboratory , 213 Carriage Lane , Delran , New Jersey 08075 , United States
| | - Charles N Haas
- Drexel University , 3141 Chestnut Street , Philadelphia , Pennsylvania 19104 , United States
| | - P L Gurian
- Drexel University , 3141 Chestnut Street , Philadelphia , Pennsylvania 19104 , United States
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19
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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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20
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Khaledi A, Bahrami A, Nabizadeh E, Amini Y, Esmaeili D. Prevalence of Legionella Species in Water Resources of Iran: A Systematic Review and Meta-Analysis. IRANIAN JOURNAL OF MEDICAL SCIENCES 2018; 43:571-580. [PMID: 30510333 PMCID: PMC6230937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Legionella species are ubiquitous and naturally found in lakes, rivers, streams and hot springs, and other water resources. The present study aimed to investigate the prevalence of Legionella species in water resources of Iran by a systematic review and meta-analysis. METHODS In search of papers relevant to the prevalence of Legionella in water resources of Iran, the scientific information database in both English and Persian languages was used. The search was limited to studies between the year 2000 and end of July 2016. Each cohort and cross-sectional study that reported the contamination of water with Legionella was included in the present study. For data analysis, comprehensive meta-analysis software with Cochran's Q and I2 tests were used. P values less than 0.05 were considered statistically significant. RESULTS The prevalence of Legionella species in water resources of Iran was 27.3% (95% CI: 25.3-29.3). The prevalence of Legionella spp. in hospital water, dental settings water, and other water resources were 28.8% (95% CI: 26.4-31.2), 23.6% (95% CI: 16.1-33.2), and 29.6% (95% CI: 25.6-33.8), respectively. The most common Legionella species was L. pneumophila with a prevalence of 60.5% (95% CI: 53.3-67.2) and the prevalence of all other species was 52.5% (95% CI: 44.7-60.2). The highest prevalence was reported in Isfahan with 55.7% (95% CI: 48.0-63.0). CONCLUSION Based on the results, the prevalence rate of Legionella species in water resources of Iran was high and the most common Legionella species was L. pneumophila.
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Affiliation(s)
- Azad Khaledi
- Infectious Disease Research Center, Kashan University of Medical Science, Kashan, Iran,Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Science, Kashan, Iran
| | - Afsane Bahrami
- Cellular and Molecular Research
Center, Birjand University of Medical
Sciences, Birjand, Iran
| | - Edris Nabizadeh
- Department of Microbiology, Faculty of
Medicine, Uremia University of Medical
Sciences, Uremia, Iran
| | - Yousef Amini
- Infectious Diseases and Tropical Medicine
Research Center, Zahedan University of
Medical Sciences, Zahedan, Iran
| | - Davoud Esmaeili
- Applied Microbiology Research Center,
Systems Biology and Poisonings
Institute, Baqiyatallah University of
Medical Sciences, Tehran, Iran
,Department of Microbiology,
Baqiyatallah University of Medical
Sciences, Tehran, Iran,Applied Virology Research Center,
Baqiyatallah University of Medical
Sciences, Tehran, Iran
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21
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Legionella Detection in Environmental Samples as an Example for Successful Implementation of qPCR. WATER 2018. [DOI: 10.3390/w10081012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Waterborne diseases are a serious threat because of their ability to infect a high number of individuals in a short time span, such as during outbreaks of Legionellosis. This significantly highlights the need for the rapid detection and quantification of bacteria in environmental water samples. The aim of this study was to investigate the feasibility of quantitative Polymerase Chain Reaction (qPCR) for the detection of Legionellapneumophila (L. pneumophila) in environmental water samples and comparison of standard culture methods for Legionella detection with qPCR. Our study reached a negative predictive value (NPV) for L. pneumophila of 80.7% and for L. pneumophila serogroup 1 (sg1) the calculated NPV was 87.0%. The positive predictive value (PPV) for L. pneumophila was 53.9% and for L. pneumophila sg1 PPV was 21.4%. Results showed a correlation between qPCR and culture with an R2 value of 0.8973 for L. pneumophila, whereas no correlation was observed for the detection of L. pneumophila sg1. In our study, qPCR proved useful for the identification of L. pneumophila negative samples. However, despite the obvious benefits (sample handling, rapid generation of results), qPCR needs to be improved regarding the PPV before it can replace culture in water quality assessment.
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22
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Palamidi I, Mountzouris KC. Diet supplementation with an organic acids-based formulation affects gut microbiota and expression of gut barrier genes in broilers. ACTA ACUST UNITED AC 2018; 4:367-377. [PMID: 30564756 PMCID: PMC6284220 DOI: 10.1016/j.aninu.2018.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 12/31/2022]
Abstract
This study was designed to study the effect of diet supplementation with an organic acids-based formulation (OABF) on luminal- and mucosa-associated bacteria, concentration of volatile fatty acids (VFA), microbial glycolytic enzyme activity and expression of mucin 2 (MUC2), immunoglobulin A (IgA) and tight junction protein, i.e., zonula occludens-1 (ZO1), zonula occludens-2 (ZO2), claudin-1 (CLDN1), claudin-5 (CLDN5) and occludin (OCLN), genes at the ileal and cecal level. A 2 × 2 factorial design was used having OABF inclusion and avilamycin as main factors. Subsequently, 544 day-old male Cobb broilers were allocated in the following 4 treatments, each with 8 replicates: no additions (CON), 1 g OABF/kg diet (OA), 2.5 mg avilamycin/kg diet (AV) and combination of OA and AV (OAAV). The trial lasted for 42 days. In the ileum, OAAV resulted in lower mucosa-associated total bacteria levels (PO × A = 0.028) compared with AV. In addition, ileal digesta levels of Clostridium perfringens subgroup were decreased by avilamycin (PA = 0.045). Inclusion of OABF stimulated the activity of microbial glycolytic enzymes, whereas avilamycin resulted in lower acetate (PA = 0.021) and higher butyrate (PA = 0.010) molar ratios. Expression of ZO1 and CLDN5 was down-regulated by both OABF (PO = 0.016 and PO = 0.003, respectively) and avilamycin (PA = 0.016 and PA = 0.001, respectively). In addition, CLDN1 was down-regulated in AV compared with CON (PO × A = 0.012). Furthermore, OABF down-regulated MUC2 (PO = 0.027), whereas avilamycin down-regulated nuclear factor kappa B subunit 1 (NFKB1) (PA = 0.024), toll-like receptor 2 family member B (TLR2B) (PA = 0.011) and toll-like receptor 4 (TLR4) (PA = 0.014) expression. In the ceca, OABF inclusion increased digesta levels of Clostridium coccoides (PO = 0.018) and Clostridium leptum (PO = 0.040) subgroups, while it up-regulated MUC2 expression (PO = 0.014). Avilamycin (PA = 0.044) and interaction (PO × A < 0.001) effects for IgA expression were noted, with CON having higher IgA expression compared with AV. In conclusion, new findings regarding OABF inclusion effects on an array of relevant biomarkers for broiler gut ecology have been reported and discussed in parallel with avilamycin effects used as a positive control. This new knowledge is expected to provide a response baseline for follow up trials under various stress and challenge conditions.
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Affiliation(s)
- Irida Palamidi
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
| | - Konstantinos C Mountzouris
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
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Dubuis ME, M'Bareche H, Veillette M, Bakhiyi B, Zayed J, Lavoie J, Duchaine C. Bioaerosols concentrations in working areas in biomethanization facilities. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2017; 67:1258-1271. [PMID: 28718709 DOI: 10.1080/10962247.2017.1356762] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/13/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED This study sought to fill the gap in information about the type and the concentration of bioaerosols present in the air of biomethanization facilities (BF). Evaluation of bioaerosol composition and concentration was achieved in two biomethanization facilities located in Eastern Canada, during summer and winter. In order to have a thorough understanding of the studied environment, the methodology combined culture of bacteria and molds, qualitiative polymerase chain reaction (qPCR) for specific microorganisms, endotoxin quantification, and next-generation sequencing (NGS) for bacterial diversity. Results revealed that workers in biomethanization facilities are exposed to bioaerosols and pathogenic microorganisms similar to those found in composting plants. However, human exposure levels to bioaerosols are lower in BF than in composting plants. Despite these differences, use of personal protective equipment is recommended to lower the risks of health problems. IMPLICATIONS Biomethanization is a new technology used in eastern Canada for waste management. In the next few years, it is expected that there will be an expansion of facilities in response of tight governmental regulations. Workers in biomethanization facilities are exposed to various amounts of bioaerosols composed of some harmful microorganisms. Therefore, monitoring this occupational exposure could be an interesting tool for improving worker's health.
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Affiliation(s)
- Marie-Eve Dubuis
- a Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval , Quebec City , Canada
- b Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie , Université Laval , Quebec City , Canada
| | - Hamza M'Bareche
- a Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval , Quebec City , Canada
| | - Marc Veillette
- a Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval , Quebec City , Canada
| | - Bouchra Bakhiyi
- c Department of Environmental and Occupational Health , School of Public Health, University of Montreal , Montreal , Canada
| | - Joseph Zayed
- c Department of Environmental and Occupational Health , School of Public Health, University of Montreal , Montreal , Canada
- d Institut de Recherche Robert-Sauvé en Santé et en Sécurité du travail (IRSST) , Montreal (Qc) , Canada
| | - Jacques Lavoie
- d Institut de Recherche Robert-Sauvé en Santé et en Sécurité du travail (IRSST) , Montreal (Qc) , Canada
| | - Caroline Duchaine
- a Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval , Quebec City , Canada
- b Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie , Université Laval , Quebec City , Canada
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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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Pierre DM, Baron J, Yu VL, Stout JE. Diagnostic testing for Legionnaires' disease. Ann Clin Microbiol Antimicrob 2017; 16:59. [PMID: 28851372 PMCID: PMC5576257 DOI: 10.1186/s12941-017-0229-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 08/01/2017] [Indexed: 11/10/2022] Open
Abstract
Legionnaires' disease is commonly diagnosed clinically using a urinary antigen test. The urinary antigen test is highly accurate for L. pneumophila serogroup 1, however other diagnostic tests should also be utilized in conjunction with the urinary antigen as many other Legionella species and serogroups are pathogenic. Culturing of patient specimens remains the gold standard for diagnosis of Legionnaires' disease. Selective media, BYCE with the addition of antibiotics, allows for a high sensitivity and specificity. Culturing can identify all species and serogroups of Legionella. A major benefit of culturing is that it provides the recovery of a patient isolate, which can be used to find an environmental match. Other diagnostic tests, including DFA and molecular tests such as PCR and LAMP, are useful tests to supplement culturing. Molecular tests provide much more rapid results in comparison to culture, however these tests should not be a primary diagnostic tool given their lower sensitivity and specificity in comparison to culturing. It is recommended that all laboratories develop the ability to culture patient specimens in-house with the selective media.
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Affiliation(s)
- David M. Pierre
- Special Pathogens Laboratory, 1401 Forbes Avenue, Pittsburgh, PA 15219 USA
| | - Julianne Baron
- Special Pathogens Laboratory, 1401 Forbes Avenue, Pittsburgh, PA 15219 USA
- University of Pittsbrugh, Pittsburgh, Pennsylvania 15219 United States
| | - Victor L. Yu
- Special Pathogens Laboratory, 1401 Forbes Avenue, Pittsburgh, PA 15219 USA
- Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA USA
| | - Janet E. Stout
- Special Pathogens Laboratory, 1401 Forbes Avenue, Pittsburgh, PA 15219 USA
- University of Pittsbrugh, Pittsburgh, Pennsylvania 15219 United States
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Temperature-related parasite infection dynamics: the case of proliferative kidney disease of brown trout. Parasitology 2017; 145:281-291. [PMID: 28831940 DOI: 10.1017/s0031182017001482] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Climate change, in particular rising temperature, is suspected to be a major driver for the emergence of many wildlife diseases. Proliferative kidney disease of salmonids, caused by the myxozoan Tetracapsuloides bryosalmonae, was used to evaluate how temperature dependence of host-parasite interactions modulates disease emergence. Brown trout (Salmo trutta fario) kept at 12 and 15 °C, were experimentally infected with T. bryosalmonae. Parasite development in the fish host and release of spores were quantified simultaneously to unravel parasite transmission potential from the vertebrate to the invertebrate host. A change to a stable plateau in infection intensity of the kidney coincided with a threshold at which spore shedding commenced. This onset of parasite release was delayed at the low temperature in accordance with reaching this infection intensity threshold, but the amount of spores released was irrespective of temperature. The production of parasite transmission stages declined with time. In conclusion, elevated temperature modifies the parasite transmission opportunities by increasing the duration of transmission stage production, which may affect the spread and establishment of the parasite in a wider range of rivers.
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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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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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Collins S, Stevenson D, Bennett A, Walker J. Occurrence of Legionella in UK household showers. Int J Hyg Environ Health 2017; 220:401-406. [DOI: 10.1016/j.ijheh.2016.12.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022]
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Pereira RPA, Peplies J, Brettar I, Höfle MG. Development of a genus-specific next generation sequencing approach for sensitive and quantitative determination of the Legionella microbiome in freshwater systems. BMC Microbiol 2017; 17:79. [PMID: 28359254 PMCID: PMC5374610 DOI: 10.1186/s12866-017-0987-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Next Generation Sequencing (NGS) has revolutionized the analysis of natural and man-made microbial communities by using universal primers for bacteria in a PCR based approach targeting the 16S rRNA gene. In our study we narrowed primer specificity to a single, monophyletic genus because for many questions in microbiology only a specific part of the whole microbiome is of interest. We have chosen the genus Legionella, comprising more than 20 pathogenic species, due to its high relevance for water-based respiratory infections. METHODS A new NGS-based approach was designed by sequencing 16S rRNA gene amplicons specific for the genus Legionella using the Illumina MiSeq technology. This approach was validated and applied to a set of representative freshwater samples. RESULTS Our results revealed that the generated libraries presented a low average raw error rate per base (<0.5%); and substantiated the use of high-fidelity enzymes, such as KAPA HiFi, for increased sequence accuracy and quality. The approach also showed high in situ specificity (>95%) and very good repeatability. Only in samples in which the gammabacterial clade SAR86 was present more than 1% non-Legionella sequences were observed. Next-generation sequencing read counts did not reveal considerable amplification/sequencing biases and showed a sensitive as well as precise quantification of L. pneumophila along a dilution range using a spiked-in, certified genome standard. The genome standard and a mock community consisting of six different Legionella species demonstrated that the developed NGS approach was quantitative and specific at the level of individual species, including L. pneumophila. The sensitivity of our genus-specific approach was at least one order of magnitude higher compared to the universal NGS approach. Comparison of quantification by real-time PCR showed consistency with the NGS data. Overall, our NGS approach can determine the quantitative abundances of Legionella species, i. e. the complete Legionella microbiome, without the need for species-specific primers. CONCLUSIONS The developed NGS approach provides a new molecular surveillance tool to monitor all Legionella species in qualitative and quantitative terms if a spiked-in genome standard is used to calibrate the method. Overall, the genus-specific NGS approach opens up a new avenue to massive parallel diagnostics in a quantitative, specific and sensitive way.
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Affiliation(s)
- Rui P A Pereira
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany.,Present address: School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Jörg Peplies
- Ribocon GmbH, Fahrenheitstraße 1, 28359, Bremen, Germany
| | - Ingrid Brettar
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Manfred G Höfle
- Department of Vaccinology and Applied Microbiology, RG Microbial Diagnostics, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, 38124, Braunschweig, Germany.
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Agarwal S, Abell V, File TM. Nosocomial (Health Care–Associated) Legionnaire's Disease. Infect Dis Clin North Am 2017; 31:155-165. [DOI: 10.1016/j.idc.2016.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Fernandez-Cassi X, Silvera C, Cervero-Aragó S, Rusiñol M, Latif-Eugeni F, Bruguera-Casamada C, Civit S, Araujo RM, Figueras MJ, Girones R, Bofill-Mas S. Evaluation of the microbiological quality of reclaimed water produced from a lagooning system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:16816-33. [PMID: 27194016 DOI: 10.1007/s11356-016-6812-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/02/2016] [Indexed: 05/07/2023]
Abstract
The use of lagooning as a complementary natural method of treating secondary effluents of wastewater treatment plants has been employed as an affordable and easy means of producing reclaimed water. However, using reclaimed water for some purposes, for example, for food irrigation, presents some risks if the effluents contain microbial pathogens. Classical bacterial indicators that are used to assess faecal contamination in water do not always properly indicate the presence of bacterial or viral pathogens. In the current study, the presence of faecal indicator bacteria (FIB), heterotrophic bacterial counts (HBC), pathogens and opportunistic pathogens, such as Legionella spp., Aeromonas spp., Arcobacter spp., free-living amoeba (FLA), several viral indicators (human adenovirus and polyomavirus JC) and viral pathogens (noroviruses and hepatitis E virus) were analysed for 1 year in inlet and outlet water to assess the removal efficiency of a lagooning system. We observed 2.58 (1.17-4.59) and 1.65 (0.15-3.14) log reductions in Escherichia coli (EC) and intestinal enterococci (IE), respectively, between the inlet and outlet samples. Genomic copies of the viruses were log reduced by 1.18 (0.24-2.93), 0.64 (0.12-1.97), 0.45 (0.04-2.54) and 0.72 (0.22-2.50) for human adenovirus (HAdV), JC polyomavirus (JCPyV) and human noroviruses (NoV GI and GII), respectively. No regrowth of opportunistic pathogens was observed within the system. FLA, detected in all samples, did not show a clear trend. The reduction of faecal pathogens was irregular with 6 out of 12 samples and 4 out of 12 samples exceeding the EC and IE values, specified in the Spanish legislation for reclaimed water (RD 1620/2007). This data evidences that there is a need for more studies to evaluate the removal mechanisms of lagooning systems in order to optimize pathogen reduction. Moreover, surveillance of water used to irrigate raw edible vegetables should be conducted to ensure the fulfilment of the microbial requirements for the production of safe reclaimed water.
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Affiliation(s)
- X Fernandez-Cassi
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
| | - C Silvera
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain
| | - S Cervero-Aragó
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
- Water Hygiene, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria
- ICC Water and Health, Vienna, Austria
| | - M Rusiñol
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - F Latif-Eugeni
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain
| | - C Bruguera-Casamada
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - S Civit
- Department of Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - R M Araujo
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - M J Figueras
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, IISPV, Universitat Rovira i Virgili, Reus, Spain
| | - R Girones
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - S Bofill-Mas
- Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
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Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures. Appl Environ Microbiol 2016; 82:2959-2965. [PMID: 26969696 DOI: 10.1128/aem.03873-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022] Open
Abstract
Physical and chemical disinfection methods have been proposed with the aim of controlling Legionella water contamination. To date, the most effective procedures for reducing bacterial contamination have not yet been defined. The aim of this study was to assess the long-term effectiveness of various disinfection procedures in order to reduce both culturable and nonculturable (NC) legionellae in different hospital water networks treated with heat, chlorine dioxide, monochloramine, and hydrogen peroxide. The temperature levels and biocide concentrations that proved to give reliable results were analyzed. In order to study the possible effects on the water pipes, we verified the extent of corrosion on experimental coupons after applying each method for 6 months. The percentage of positive points was at its lowest after treatment with monochloramine, followed by chlorine dioxide, hydrogen peroxide, and hyperthermia. Different selections of Legionella spp. were observed, as networks treated with chlorine-based disinfectants were contaminated mainly by Legionella pneumophila serogroup 1, hyperthermia was associated with serogroups 2 to 14, and hydrogen peroxide treatment was associated mainly with non-pneumophila species. NC cells were detected only in heat-treated waters, and also when the temperature was approximately 60°C. The corrosion rates of the coupons were within a satisfactory limit for water networks, but the morphologies differed. We confirm here that chemical disinfection controls Legionella colonization more effectively than hyperthermia does. Monochloramine was the most effective treatment, while hydrogen peroxide may be a promising alternative to chlorine-based disinfectants due to its ability to select for other, less virulent or nonpathogenic species.
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Seidl M, Da G, Ausset P, Haenn S, Géhin E, Moulin L. Evaluating exposure of pedestrians to airborne contaminants associated with non-potable water use for pavement cleaning. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:6091-6101. [PMID: 26233734 DOI: 10.1007/s11356-015-5062-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/09/2015] [Indexed: 06/04/2023]
Abstract
Climate change and increasing demography press local authorities to look after affordable water resources and replacement of drinking water for city necessities like street and pavement cleaning by more available raw water. Though, the substitution of drinking by non-drinking resources demands the evaluation of sanitary hazards. This article aims therefore to evaluate the contribution of cleaning water to the overall exposure of city dwellers in case of wet pavement cleaning using crossed physical, chemical and biological approaches. The result of tracer experiments with fluorescein show that liquid water content of the cleaning aerosol produced is about 0.24 g m(-3), rending possible a fast estimation of exposure levels. In situ analysis of the aerosol particles indicates a significant increase in particle number concentration and particle diameter, though without change in particle composition. The conventional bacterial analysis using total coliforms as tracer suggests that an important part of the contamination is issued from the pavement. The qPCR results show a more than 20-fold increase of background genome concentration for Escherichia coli and 10-fold increase for Enterococcus but a negligible contribution of the cleaning water. The fluorescence analysis of the cleaning aerosol confirms the above findings identifying pavement surface as the major contributor to aerosol organic load. The physical, chemical and microbiological approaches used make it possible to describe accurately the cleaning bioaerosol and to identify the existence of significantly higher levels of all parameters studied during the wet pavement cleaning. Though, the low level of contamination and the very short time of passage of pedestrian in the zone do not suggest a significant risk for the city dwellers. As the cleaning workers remain much longer in the impacted area, more attention should be paid to their chronic exposure.
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Affiliation(s)
- M Seidl
- Université Paris-Est, Laboratoire Eau Environnement et Systèmes Urbains (LEESU), UMR MA 102, ENPC, 6 Ave Blaise Pascal, 77455, Champs-sur-Marne, France.
| | - G Da
- Université Paris-Est, Centre d'Études et de Recherche en Thermique, Environnement et Systèmes EA 3481 (CERTES), Université Paris-Est Créteil, 61 Ave du Général de Gaulle, 94010, Créteil Cedex, France
| | - P Ausset
- Université Paris-Est, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583 UPEC - UP7, Université Paris-Est Créteil, 61 Ave du Général de Gaulle, 94010, Créteil, France
| | - S Haenn
- Eau de Paris, Direction de la Recherche & Développement et de la Qualité des Eaux (DRDQE), 33 Ave Jean Jaurès, 94200, Ivry Sur Seine, France
| | - E Géhin
- Université Paris-Est, Centre d'Études et de Recherche en Thermique, Environnement et Systèmes EA 3481 (CERTES), Université Paris-Est Créteil, 61 Ave du Général de Gaulle, 94010, Créteil Cedex, France
| | - L Moulin
- Eau de Paris, Direction de la Recherche & Développement et de la Qualité des Eaux (DRDQE), 33 Ave Jean Jaurès, 94200, Ivry Sur Seine, France
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Hanabara Y, Ueda Y. A Rapid and Simple Real-Time PCR Assay for Detecting Foodborne Pathogenic Bacteria in Human Feces. Jpn J Infect Dis 2016; 69:471-476. [DOI: 10.7883/yoken.jjid.2015.205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Yutaro Hanabara
- Tottori Prefectural Institute of Public Health and Environment
| | - Yutaka Ueda
- Tottori Prefectural Institute of Public Health and Environment
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Edagawa A, Kimura A, Kawabuchi-Kurata T, Adachi S, Furuhata K, Miyamoto H. Investigation of Legionella Contamination in Bath Water Samples by Culture, Amoebic Co-Culture, and Real-Time Quantitative PCR Methods. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:13118-30. [PMID: 26492259 PMCID: PMC4627020 DOI: 10.3390/ijerph121013118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 11/16/2022]
Abstract
We investigated Legionella contamination in bath water samples, collected from 68 bathing facilities in Japan, by culture, culture with amoebic co-culture, real-time quantitative PCR (qPCR), and real-time qPCR with amoebic co-culture. Using the conventional culture method, Legionella pneumophila was detected in 11 samples (11/68, 16.2%). Contrary to our expectation, the culture method with the amoebic co-culture technique did not increase the detection rate of Legionella (4/68, 5.9%). In contrast, a combination of the amoebic co-culture technique followed by qPCR successfully increased the detection rate (57/68, 83.8%) compared with real-time qPCR alone (46/68, 67.6%). Using real-time qPCR after culture with amoebic co-culture, more than 10-fold higher bacterial numbers were observed in 30 samples (30/68, 44.1%) compared with the same samples without co-culture. On the other hand, higher bacterial numbers were not observed after propagation by amoebae in 32 samples (32/68, 47.1%). Legionella was not detected in the remaining six samples (6/68, 8.8%), irrespective of the method. These results suggest that application of the amoebic co-culture technique prior to real-time qPCR may be useful for the sensitive detection of Legionella from bath water samples. Furthermore, a combination of amoebic co-culture and real-time qPCR might be useful to detect viable and virulent Legionella because their ability to invade and multiply within free-living amoebae is considered to correlate with their pathogenicity for humans. This is the first report evaluating the efficacy of the amoebic co-culture technique for detecting Legionella in bath water samples.
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Affiliation(s)
- Akiko Edagawa
- Division of Environment Health, Osaka Prefectural Institute of Public Health, Osaka 537-0025, Japan.
- Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga 849-8501, Japan.
| | - Akio Kimura
- Division of Planning and Coordination, Osaka Prefectural Institute of Public Health, Osaka 537-0025, Japan.
| | | | - Shinichi Adachi
- Division of Environment Health, Osaka Prefectural Institute of Public Health, Osaka 537-0025, Japan.
| | - Katsunori Furuhata
- School of Life and Environmental Science, Azabu University, Kanagawa 252-5201, Japan.
| | - Hiroshi Miyamoto
- Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga 849-8501, Japan.
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Janczarek M, Palusińska-Szysz M. PCR method for the rapid detection and discrimination of Legionella spp. based on the amplification of pcs, pmtA, and 16S rRNA genes. J Appl Genet 2015; 57:251-61. [PMID: 26423783 DOI: 10.1007/s13353-015-0317-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/18/2015] [Accepted: 09/14/2015] [Indexed: 10/23/2022]
Abstract
Legionella bacteria are organisms of public health interest due to their ability to cause pneumonia (Legionnaires' disease) in susceptible humans and their ubiquitous presence in water supply systems. Rapid diagnosis of Legionnaires' disease allows the use of therapy specific for the disease. L. pneumophila serogroup 1 is the most common cause of infection acquired in community and hospital environments. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this work, simplex and duplex PCR assays with the use of new molecular markers pcs and pmtA involved in phosphatidylcholine synthesis were specified for rapid and cost-efficient identification and distinguishing Legionella species. The sets of primers developed were found to be sensitive and specific for reliable detection of Legionella belonging to the eight most clinically relevant species. Among these, four primer sets I, II, VI, and VII used for duplex-PCRs proved to have the highest identification power and reliability in the detection of the bacteria. Application of this PCR-based method should improve detection of Legionella spp. in both clinical and environmental settings and facilitate molecular typing of these organisms.
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Affiliation(s)
- Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033, Lublin, Poland
| | - Marta Palusińska-Szysz
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033, Lublin, Poland.
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Collins S, Jorgensen F, Willis C, Walker J. Real-time PCR to supplement gold-standard culture-based detection of Legionella
in environmental samples. J Appl Microbiol 2015. [DOI: 10.1111/jam.12911] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Collins
- Public Health England; Biosafety Investigation Unit; Salisbury UK
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - F. Jorgensen
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - C. Willis
- Public Health England; Food, Water and Environmental Microbiology Laboratory; Salisbury UK
| | - J. Walker
- Public Health England; Biosafety Investigation Unit; Salisbury UK
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Ditommaso S, Giacomuzzi M, Ricciardi E, Zotti CM. Viability-qPCR for detecting Legionella: Comparison of two assays based on different amplicon lengths. Mol Cell Probes 2015; 29:237-43. [DOI: 10.1016/j.mcp.2015.05.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 11/24/2022]
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Omiccioli E, Schiavano GF, Ceppetelli V, Amagliani G, Magnani M, Brandi G. Validation according to ISO/TS 12869:2012 of a molecular method for the isolation and quantification of Legionella spp. in water. Mol Cell Probes 2015; 29:86-91. [DOI: 10.1016/j.mcp.2014.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 10/24/2022]
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Ditommaso S, Ricciardi E, Giacomuzzi M, Arauco Rivera SR, Zotti CM. Legionella in water samples: How can you interpret the results obtained by quantitative PCR? Mol Cell Probes 2015; 29:7-12. [DOI: 10.1016/j.mcp.2014.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/09/2014] [Accepted: 09/09/2014] [Indexed: 11/29/2022]
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Ditommaso S, Ricciardi E, Giacomuzzi M, Arauco Rivera SR, Ceccarelli A, Zotti CM. Overestimation of the Legionella spp. load in environmental samples by quantitative real-time PCR: pretreatment with propidium monoazide as a tool for the assessment of an association between Legionella concentration and sanitary risk. Diagn Microbiol Infect Dis 2014; 80:260-6. [PMID: 25284373 DOI: 10.1016/j.diagmicrobio.2014.09.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/08/2014] [Accepted: 09/08/2014] [Indexed: 11/29/2022]
Abstract
Quantitative polymerase chain reaction (qPCR) offers rapid, sensitive, and specific detection of Legionella in environmental water samples. In this study, qPCR and qPCR combined with propidium monoazide (PMA-qPCR) were both applied to hot-water system samples and compared to traditional culture techniques. In addition, we evaluated the ability of PMA-qPCR to monitor the efficacy of different disinfection strategies. Comparison between the quantification obtained by culture and by qPCR or PMA-qPCR on environmental water samples confirms that the concentration of Legionella estimated by GU/L is generally higher than that estimated in CFU/L. Our results on 57 hot-water-system samples collected from 3 different sites show that: i) qPCR results were on average 178-fold higher than the culture results (Δ log10=2.25), ii) PMA-qPCR results were on average 27-fold higher than the culture results (Δ log10=1.43), iii) propidium monoazide-induced signal reduction in qPCR were nearly 10-fold (Δ log10=0.95), and that iv) different degrees of correlations between the 3 methods might be explained by different matrix properties, but also by different disinfection methods affecting cultivability of Legionella. In our study, we calculated the logarithmic differences between the results obtained by PMA-qPCR and those obtained by culture, and we suggested an algorithm for the interpretation of PMA-qPCR results for the routine monitoring of healthcare water systems using a commercial qPCR system (iQ-check real-time PCR kit; Bio-Rad, Marnes-la-Coquette, France).
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Affiliation(s)
- Savina Ditommaso
- Department of Public Health and Pediatrics, University of Turin, Italy.
| | - Elisa Ricciardi
- Department of Public Health and Pediatrics, University of Turin, Italy
| | - Monica Giacomuzzi
- Department of Public Health and Pediatrics, University of Turin, Italy
| | | | - Adriano Ceccarelli
- Department of Clinical and Biological Sciences, University of Turin, Italy
| | - Carla M Zotti
- Department of Public Health and Pediatrics, University of Turin, Italy
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Taylor MJ, Bentham RH, Ross KE. Limitations of Using Propidium Monoazide with qPCR to Discriminate between Live and Dead Legionella in Biofilm Samples. Microbiol Insights 2014; 7:15-24. [PMID: 25288885 PMCID: PMC4167484 DOI: 10.4137/mbi.s17723] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 01/17/2023] Open
Abstract
Accurately quantifying Legionella for regulatory purposes to protect public health is essential. Real-time PCR (qPCR) has been proposed as a better method for detecting and enumerating Legionella in samples than conventional culture method. However, since qPCR amplifies any target DNA in the sample, the technique’s inability to discriminate between live and dead cells means that counts are generally significantly overestimated. Propidium monoazide (PMA) has been used successfully in qPCR to aid live/dead discrimination. We tested PMA use as a method to count only live Legionella cells in samples collected from a modified chemostat that generates environmentally comparable samples. Counts from PMA-treated samples that were pretreated with either heat or three types of disinfectants (to kill the cells) were highly variable, with the only consistent trend being the relationship between biofilm mass and numbers of Legionella cells. Two possibilities explain this result: 1. PMA treatment worked and the subsequent muted response of Legionella to disinfection treatment is a factor of biofilm/microbiological effects; although this does not account for the relationship between the amount of biofilm sampled and the viable Legionella count as determined by PMA-qPCR; or 2. PMA treatment did not work, and any measured decrease or increase in detectable Legionella is because of other factors affecting the method. This is the most likely explanation for our results, suggesting that higher concentrations of PMA might be needed to compensate for the presence of other compounds in an environmental sample or that lower amounts of biofilm need to be sampled. As PMA becomes increasingly toxic at higher concentrations and is very expensive, augmenting the method to include higher PMA concentrations is both counterproductive and cost prohibitive. Conversely, if smaller volumes of biofilm are used, the reproducibility of the method is reduced. Our results suggest that using PMA is not an appropriate method for discriminating between live and dead cells to enumerate Legionella for regulatory purposes.
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Affiliation(s)
- Michael J Taylor
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
| | - Richard H Bentham
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
| | - Kirstin E Ross
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
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Kao PM, Hsu BM, Hsu TK, Ji WT, Huang PH, Hsueh CJ, Chiang CS, Huang SW, Huang YL. Application of TaqMan fluorescent probe-based quantitative real-time PCR assay for the environmental survey of Legionella spp. and Legionella pneumophila in drinking water reservoirs in Taiwan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 490:416-421. [PMID: 24867705 DOI: 10.1016/j.scitotenv.2014.04.103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 06/03/2023]
Abstract
In this study, TaqMan fluorescent quantitative real-time PCR was performed to quantify Legionella species in reservoirs. Water samples were collected from 19 main reservoirs in Taiwan, and 12 (63.2%) were found to contain Legionella spp. The identified species included uncultured Legionella spp., L. pneumophila, L. jordanis, and L. drancourtii. The concentrations of Legionella spp. and L. pneumophila in the water samples were in the range of 1.8×10(2)-2.6×10(3) and 1.6×10(2)-2.4×10(2) cells/L, respectively. The presence and absence of Legionella spp. in the reservoir differed significantly in pH values. These results highlight the importance that L. pneumophila, L. jordanis, and L. drancourtii are potential pathogens in the reservoirs. The presence of L. pneumophila in reservoirs may be a potential public health concern that must be further examined.
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Affiliation(s)
- Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
| | - Tsui-Kang Hsu
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan, ROC
| | - Wen-Tsai Ji
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Po-Hsiang Huang
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Chih-Jen Hsueh
- Department of Otorhinolaryngology, Cheng Hsin General Hospital, Taipei, Taiwan, ROC
| | - Chuen-Sheue Chiang
- Research and Diagnostic Center, Centers for Disease Control, Taiwan, ROC
| | - Shih-Wei Huang
- Center for General Education, Cheng-Shiu University, Kaohsiung, Taiwan, ROC
| | - Yu-Li Huang
- Department of Safety Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan, ROC
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Rafiee M, Jahangiri-rad M, Hajjaran H, Mesdaghinia A, Hajaghazadeh M. Detection and identification of Legionella species in hospital water supplies through Polymerase Chain Reaction (16S rRNA). JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2014; 12:83. [PMID: 24860661 PMCID: PMC4032159 DOI: 10.1186/2052-336x-12-83] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 04/20/2014] [Indexed: 06/03/2023]
Abstract
Legionella spp. are important waterborne pathogens that are normally transmitted through aerosols. The present work was conducted to investigate the presence of Legionella spp. and its common species in hospital water supplies. Considering the limitations of culture method, polymerase chain reaction (PCR) assays were developed to detect the gene 16S rRNA irrespective of the bacterial serotype. Four well-established DNA extraction protocols (freeze & thaw and phenol-chloroform as two manual protocols and two commercial kits) were tested and evaluated to release DNA from bacterial cells. A total of 45 samples were collected from seven distinct hospitals' sites during a period of 10 months. The PCR assay was used to amplify a 654-bp fragment of the 16S rRNA gene. Legionella were detected in 13 samples (28.9%) by all of the methods applied for DNA extraction. Significant differences were noted in the yield of extracted nucleic acids. Legionella were not detected in any of the samples when DNA extraction by freeze & thaw was used. Excluding this method and comparing manual protocol with commercial kits, Kappa coefficient was calculated as 0.619 with p < 0.05. Although no meaningful differences were found between the kits, DNA extraction with Bioneer kit exhibited a higher sensitivity than classical Qiagen. Showerheads and cold-water taps were the most and least contaminated sources with 55.5 and 9 percent positive samples, respectively. Moreover two positive samples were identified for species by DNA sequencing and submitted to the Gene Bank database with accession Nos. FJ480932 and FJ480933. The results obtained showed that despite the advantages of molecular assays in Legionella tracing in environmental sources, the use of optimised DNA extraction methods is critical.
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Affiliation(s)
- Mohammad Rafiee
- Department of Environmental Health Engineering, School of Public Health, Alborz University of Medical Sciences, Alborz, Iran
| | - Mahsa Jahangiri-rad
- Department of Environmental Health Engineering, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran
| | - Homa Hajjaran
- Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Mesdaghinia
- Department of Environmental Health Engineering, School of Public Health, Center for Water Quality Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Hajaghazadeh
- Department of Occupational Health, Health Faculty, Urmia University of Medical Sciences, Urmia, Iran
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The Efficacy of Residual Chlorine Content on the Control of Legionella Spp. In Hospital Water Systems. IRANIAN JOURNAL OF PUBLIC HEALTH 2014; 43:637-44. [PMID: 26060765 PMCID: PMC4449412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 02/10/2014] [Indexed: 10/26/2022]
Abstract
BACKGROUND Outbreaks of legionellosis may be a side effect of institution-water treatment. However, the long-term outcomes and the predictive factors of Legionella prevalence in such systems have still not been fully studied. This study was therefore conducted to investigate the prevalence of Legionella spp. and to evaluate the role of bacteriological water quality parameters on its prevalence and removal in hospital water systems. METHODS A total of 45 samples were collected from distinct sites at seven hospitals in Tehran, Iran. The prevalence of this bacterium was assayed through a sensitive and specific technique for DNA detection using PCR. Multivariable stepwise regression analysis was used to explore the independent effects of the baseline factors on the incidence of Legionella. Two positive samples were also identified for species by DNA sequencing. RESULTS Legionella were detected in 31.1% of samples. Showerheads and cold-water taps were the most and the least contaminated sources with 55.3 and 9 percent positive samples, respectively. Total mean of residual chlorine was 0.38 mg/L, with the peak value of 1.7 mg/L. Legionella detection was proportional to the residual chlorine content of water and the results indicated that residual chlorine content is a critical factor in the incidence and proliferation of Legionella (r=-0.33). The prevalence of Legionella also coincided with the prevalence of HPC and amoeba cysts. CONCLUSION The high positive rate of Legionella colonization shows that hospital-acquired legionellosis might be under diagnosed in studied hospitals. Further, Legionella colonization is independent of the type of water, system characteristics and of preventive maintenance measures.
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Strepparava N, Wahli T, Segner H, Petrini O. Detection and quantification of Flavobacterium psychrophilum in water and fish tissue samples by quantitative real time PCR. BMC Microbiol 2014; 14:105. [PMID: 24767577 PMCID: PMC4005812 DOI: 10.1186/1471-2180-14-105] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 04/22/2014] [Indexed: 11/10/2022] Open
Abstract
Background Flavobacterium psychrophilum is the agent of Bacterial Cold Water Disease and Rainbow Trout Fry Syndrome, two diseases leading to high mortality. Pathogen detection is mainly carried out using cultures and more rapid and sensitive methods are needed. Results We describe a qPCR technique based on the single copy gene β’ DNA-dependent RNA polymerase (rpoC). Its detection limit was 20 gene copies and the quantification limit 103 gene copies per reaction. Tests on spiked spleens with known concentrations of F. psychrophilum (106 to 101 cells per reaction) showed no cross-reactions between the spleen tissue and the primers and probe. Screening of water samples and spleens from symptomless and infected fishes indicated that the pathogen was already present before the outbreaks, but F. psychrophilum was only quantifiable in spleens from diseased fishes. Conclusions This qPCR can be used as a highly sensitive and specific method to detect F. psychrophilum in different sample types without the need for culturing. qPCR allows a reliable detection and quantification of F. psychrophilum in samples with low pathogen densities. Quantitative data on F. psychrophilum abundance could be useful to investigate risk factors linked to infections and also as early warning system prior to potential devastating outbreak.
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Affiliation(s)
- Nicole Strepparava
- Laboratory of Applied Microbiology, University of Applied Sciences and Arts of Southern Switzerland, Via Mirasole 22a, 6500 Bellinzona, Switzerland.
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48
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Donohue MJ, O'Connell K, Vesper SJ, Mistry JH, King D, Kostich M, Pfaller S. Widespread molecular detection of Legionella pneumophila Serogroup 1 in cold water taps across the United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:3145-3152. [PMID: 24548208 DOI: 10.1021/es4055115] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In the United States, 6,868 cases of legionellosis were reported to the Center for Disease Control and Prevention in 2009-2010. Of these reports, it is estimated that 84% are caused by the microorganism Legionella pneumophila Serogroup (Sg) 1. Legionella spp. have been isolated and recovered from a variety of natural freshwater environments. Human exposure to L. pneumophila Sg1 may occur from aerosolization and subsequent inhalation of household and facility water. In this study, two primer/probe sets (one able to detect L. pneumophila and the other L. pneumophila Sg1) were determined to be highly sensitive and selective for their respective targets. Over 272 water samples, collected in 2009 and 2010 from 68 public and private water taps across the United States, were analyzed using the two qPCR assays to evaluate the incidence of L. pneumophila Sg1. Nearly half of the taps showed the presence of L. pneumophila Sg1 in one sampling event, and 16% of taps were positive in more than one sampling event. This study is the first United States survey to document the occurrence and colonization of L. pneumophila Sg1 in cold water delivered from point of use taps.
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Affiliation(s)
- Maura J Donohue
- Office of Research and Development, National Exposure Research Laboratory, United States Environmental Protection Agency , 26 West Martin Luther King Drive, Mail Stop 593, Cincinnati, Ohio 45268, United States
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Abstract
Legionella spp. are the causative agent of Legionnaire's disease and an opportunistic pathogen of significant public health concern. Identification and quantification from environmental sources is crucial for identifying outbreak origins and providing sufficient information for risk assessment and disease prevention. Currently there are a range of methods for Legionella spp. quantification from environmental sources, but the two most widely used and accepted are culture and real-time polymerase chain reaction (qPCR). This paper provides a review of these two methods and outlines their advantages and limitations. Studies from the last 10 years which have concurrently used culture and qPCR to quantify Legionella spp. from environmental sources have been compiled. 26/28 studies detected Legionella at a higher rate using qPCR compared to culture, whilst only one study detected equivalent levels of Legionella spp. using both qPCR and culture. Aggregating the environmental samples from all 28 studies, 2856/3967 (72%) tested positive for the presence of Legionella spp. using qPCR and 1331/3967 (34%) using culture. The lack of correlation between methods highlights the need to develop an acceptable standardized method for quantification that is sufficient for risk assessment and management of this human pathogen.
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Affiliation(s)
- Harriet Whiley
- a Department of Health and the Environment , Flinders University , Adelaide , Australia
| | - Michael Taylor
- a Department of Health and the Environment , Flinders University , Adelaide , Australia
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Mansi A, Amori I, Marchesi I, Marcelloni A, Proietto A, Ferranti G, Magini V, Valeriani F, Borella P. Legionella spp. survival after different disinfection procedures: Comparison between conventional culture, qPCR and EMA–qPCR. Microchem J 2014. [DOI: 10.1016/j.microc.2013.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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