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Trigui H, Matthews S, Bedard E, Charron D, Chea S, Fleury C, Maldonado JFG, Rivard M, Faucher SP, Prévost M. Assessment of monitoring approaches to control Legionella pneumophila within a complex cooling tower system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175136. [PMID: 39084374 DOI: 10.1016/j.scitotenv.2024.175136] [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: 03/19/2024] [Revised: 07/24/2024] [Accepted: 07/28/2024] [Indexed: 08/02/2024]
Abstract
Precise and rapid methods are needed to improve monitoring approaches of L. pneumophila (Lp) in cooling towers (CTs) to allow timely operational adjustments and prevent outbreaks. The performance of liquid culture (ASTM D8429-21) and an online qPCR device were first compared to conventional filter plate culture (ISO 11731-2017), qPCR and semi-automated qPCR at three spiked concentrations of Lp (serogroup 1) validated by flow cytometry (total/viable cell count). The most accurate was qPCR, followed by liquid culture, online and semi-automated qPCR, and lastly, by a significant margin, filter plate culture. An industrial CT system was monitored using liquid and direct plate culture by the facility, qPCR and online qPCR. Direct plate and liquid culture results agreed at regulatory sampling point, supporting the use of the faster liquid culture for monitoring culturable Lp. During initial operation, qPCR and online qPCR results were within one log of culture at the primary pump before deviating after first cleaning. Other points revealed high spatial variability of Lp. The secondary pumps and chiller had the most positivity and highest concentrations by both qPCR and liquid culture compared to the basin and infeed tank. Altogether, this suggests that results from monthly compliance sampling at a single location with plate culture are not representative of Lp risks in this CT due to the high temporal and spatial variability. The primary pump, rather than the CT basin, should be designated for sampling, as it is representative of the health risk. An annual multi point survey of the system should be conducted to identify and target Lp hot spots. Generally, a combination of liquid culture for compliance and frequent qPCR for process control provides a more agile and robust monitoring scheme than plate culture alone, enabling early treatment adjustments, due to lower limit of detection (LOD) and turnover time.
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Affiliation(s)
- Hana Trigui
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada
| | - Sara Matthews
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue H9X 3V9, Québec, Canada
| | - Emilie Bedard
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada
| | - Dominique Charron
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada.
| | - Sakona Chea
- Direction de l'épuration des eaux usées, Service de l'eau, Ville de Montréal, Montréal H1C 1V3, Québec, Canada
| | - Carole Fleury
- Direction de l'épuration des eaux usées, Service de l'eau, Ville de Montréal, Montréal H1C 1V3, Québec, Canada
| | - Juan Francisco Guerra Maldonado
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada
| | - Mélanie Rivard
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue H9X 3V9, Québec, Canada
| | - Michèle Prévost
- Polytechnique Montréal, Civil, Geological and Mining Engineering Dpt., P.O. Box 6079, Succ. Centre-ville, Montréal H3C 3A7, Québec, Canada
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Yin X, Chen YZ, Ye QQ, Liao LJ, Cai ZR, Lin M, Li JN, Zhang GB, Peng XL, Shi WF, Guo XG. Detection performance of PCR for Legionella pneumophila in environmental samples: a systematic review and meta-analysis. Ann Clin Microbiol Antimicrob 2022; 21:12. [PMID: 35303873 PMCID: PMC8934000 DOI: 10.1186/s12941-022-00503-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/07/2022] [Indexed: 11/25/2022] Open
Abstract
Background Legionellosis remains a public health problem. The most common diagnostic method to detect Legionella pneumophila (L. pneumophila) is culture. Polymerase chain reaction (PCR) is a fast and accurate method for this detection in environmental samples. Methods Four databases were searched for studies that evaluated the detection efficiency of PCR in L. pneumophila. The quality evaluation was conducted using Review Manager 5.3. We used Meta-DiSc 1.4 software and the Stata 15.0 software to create forest plots, a meta-regression, a bivariate boxplot and a Deeks’ funnel plot. Results A total of 18 four-fold tables from 16 studies were analysed. The overall pooled sensitivity and specificity of PCR was 94% and 72%, respectively. The positive likelihood ratio (RLR) and negative likelihood ratio (NLR) was 2.73 and 0.12, respectively. The result of the diagnostic odds ratio (DOR) was 22.85 and the area under the curve (AUC) was 0.7884. Conclusion Establishing a laboratory diagnostic tool for L. pneumophila detection is important for epidemiological studies. In this work, PCR demonstrated a promising diagnostic accuracy for L. pneumophila. Supplementary Information The online version contains supplementary material available at 10.1186/s12941-022-00503-9.
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Affiliation(s)
- Xin Yin
- Department of Clinical Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.,Department of Pediatrics, The Pediatrics School of Guangzhou Medical University, Guangzhou, 510182, China
| | - Ying-Zhou Chen
- Department of Clinical Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.,Department of Clinical Medicine, The First Clinical School of Guangzhou Medical University, Guangzhou, 511436, China
| | - Qi-Qing Ye
- Department of Clinical Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.,Department of Pediatrics, The Pediatrics School of Guangzhou Medical University, Guangzhou, 510182, China
| | - Li-Juan Liao
- Department of Clinical Medicine, The First Clinical School of Guangzhou Medical University, Guangzhou, 511436, China
| | - Zhuo-Rui Cai
- Department of Preventive Medicine, The School of Public Health of Guangzhou Medical University, Guangzhou, 511436, China
| | - Min Lin
- Department of Traditional Chinese and Western Medicine in Clinical Medicine, The Clinical School of Traditional Chinese and Western Medicine of Guangzhou Medical University, Guangzhou, 511436, China
| | - Jia-Na Li
- Department of Medical Imaging, The Second Clinical School of Guangzhou Medical University, Guangzhou, 511436, China
| | - Geng-Biao Zhang
- Department of Medical Imaging, The Second Clinical School of Guangzhou Medical University, Guangzhou, 511436, China
| | - Xiao-Li Peng
- Department of Traditional Chinese and Western Medicine in Clinical Medicine, The Clinical School of Traditional Chinese and Western Medicine of Guangzhou Medical University, Guangzhou, 511436, China
| | - Wen-Fang Shi
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 511436, China
| | - Xu-Guang Guo
- Department of Clinical Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China. .,Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 511436, China. .,Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China. .,Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.
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Walker JT, McDermott PJ. Confirming the Presence of Legionella pneumophila in Your Water System: A Review of Current Legionella Testing Methods. J AOAC Int 2021; 104:1135-1147. [PMID: 33484265 PMCID: PMC8378878 DOI: 10.1093/jaoacint/qsab003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/24/2022]
Abstract
Legionnaires' disease has been recognized since 1976 and Legionella pneumophila still accounts for more than 95% of cases. Approaches in countries, including France, suggest that focusing risk reduction specifically on L. pneumophila is an effective strategy, as detecting L. pneumophila has advantages over targeting multiple species of Legionella. In terms of assays, the historically accepted plate culture method takes 10 days for confirmed Legionella spp. results, has variabilities which affect trending and comparisons, requires highly trained personnel to identify colonies on a plate in specialist laboratories, and does not recover viable-but-non-culturable bacteria. PCR is sensitive, specific, provides results in less than 24 h, and determines the presence/absence of Legionella spp. and/or L. pneumophila DNA. Whilst specialist personnel and laboratories are generally required, there are now on-site PCR options, but there is no agreement on comparing genome units to colony forming units and action limits. Immunomagnetic separation assays are culture-independent, detect multiple Legionella species, and results are available in 24 h, with automated processing options. Field-use lateral flow devices provide presence/absence determination of L. pneumophila serogroup 1 where sufficient cells are present, but testing potable waters is problematic. Liquid culture most probable number (MPN) assays provide confirmed L. pneumophila results in 7 days that are equivalent to or exceed plate culture, are robust and reproducible, and can be performed in a variety of laboratory settings. MPN isolates can be obtained for epidemiological investigations. This accessible, non-technical review will be of particular interest to building owners, operators, risk managers, and water safety groups and will enable them to make informed decisions to reduce the risk of L. pneumophila.
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Nuthong B, Wilailuckana C, Tavichakorntrakool R, Boonsiri P, Daduang S, Bunyaraksyotin G, Suphan O, Daduang J. One step for Legionella pneumophila detection in environmental samples by DNA-gold nanoparticle probe. J Appl Microbiol 2018; 125:1534-1540. [PMID: 30027603 DOI: 10.1111/jam.14047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/28/2018] [Accepted: 07/10/2018] [Indexed: 11/30/2022]
Abstract
AIMS To develop and evaluate a DNA-gold nanoparticle (DNA-AuNP) probe assay to detect Legionella pneumophila, which causes Legionnaires' disease, compared with the gold standard culture method. METHODS AND RESULTS Gold nanoparticles (AuNPs) were conjugated with DNA probes to detect the mip gene of L. pneumophila. The DNA-AuNP probe assay was evaluated for its specificity, sensitivity and stability. The results showed that only L. pneumophila mixed with this probe resulted in a red solution that was easily detected by the naked eye, and the colour was stable when 10 mmol l-1 MgSO4 was added. The 100 Legionella isolates and 10 other bacteria led to 100% specificity. Compared with the culture method, our method showed a 100% negative predictive value, 100% sensitivity (kappa = 0·87), and a detection limit of 4·5 ng DNA μl-1 with a 6-min response time for the 124 colonies suspected of being Legionella. The DNA-AuNP probe reagents were stable for more than 6 months. CONCLUSIONS The developed DNA-AuNP probe assay has good negative predictive value, sensitivity, rapidity and ease of use, which is helpful for ruling out negative samples. SIGNIFICANCE AND IMPACT OF THE STUDY The DNA-AuNP probe assay can detect the mip gene of L. pneumophila. Therefore, it may be an alternative method for screening colonies suspected of being L. pneumophila.
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Affiliation(s)
- B Nuthong
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Regional Medical Sciences Center Phuket, Department of Medical Sciences, Phuket, Thailand
| | - C Wilailuckana
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - R Tavichakorntrakool
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - P Boonsiri
- Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - S Daduang
- Division of Pharmacognosy and Toxicology, Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - G Bunyaraksyotin
- Regional Medical Sciences Center Phuket, Department of Medical Sciences, Phuket, Thailand
| | - O Suphan
- Regional Medical Sciences Center Phuket, Department of Medical Sciences, Phuket, Thailand
| | - J Daduang
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
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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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Ghanizadeh G, Mirmohamadlou A, Esmaeli D. Predictive parameters of Legionella pneumophila occurrence in hospital water: HPCs and plumbing system installation age. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:536. [PMID: 27573071 DOI: 10.1007/s10661-016-5554-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
Occurrence of Legionella pneumophila can be relevant to the installation age and the presence of heterotrophic plate counts (HPCs). This research illustrates L. pneumophila contamination of hospital water in accordance with the installation age and the presence of HPCs. One hundred and fifty samples were collected from hot and cold water systems and cultured on R2A and BCYE agar. L. pneumophila identification was done via specific biochemical tests. HPCs and L. pneumophila were detected in 96 and 37.3 % of the samples, respectively. The mean of HPCs density was 947 ± 998 CFU/ml; therefore, 52 % of the samples had higher densities than 500 CFU/ml. High densities of HPCs (>500 CFU/ml) led to colonization of L. pneumophila (≥1000 CFU/ml), mainly observed in cooling systems, gynecological, sonography, and NICU wards. Chi(2) test demonstrated that higher densities (>500 CFU/ml) of HPCs and L. pneumophila contamination in cold water were more frequent than warm water (OR: 2.3 and 1.49, respectively). Univariate regressions implied a significant difference between HPCs density and installation age in positive and negative tests of L. pneumophila (OR = 1.1, p < 0.001, OR = 1.2, p < 0.001). Mann-Whitney U test implied the significant effects of HPCs and installation age on L. pneumophila occurrences (p < 0.001). Spearman correlation and multivariate linear regression revealed significant differences between L. pneumophila and HPCs densities (r s = 0.33, p < 0.001 and ß = 0.11, p = 0.02), but nonsignificant difference with installation age (r s = 0.33, p < 0.001 and ß = 0.0, p = 0.91). The occurrence of L. pneumophila, HPCs, and installation age are relevant; so, plumbing system renovation with appropriate materials and promotion of the effective efforts for hospital's water quality assurance is highly recommended.
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Affiliation(s)
- Ghader Ghanizadeh
- Environmental Health Department, Health School, Baqiyatallah University of Medical Sciences, South Sheykhbahaee Ave, Nosrat Alley, Tehran, Iran.
| | - Ali Mirmohamadlou
- Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Davoud Esmaeli
- Medical Bacteriology Department, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Ahmadrajabi R, Shakibaie MR, Iranmanesh Z, Mollaei HR, Sobhanipoor MH. Prevalence of mip virulence gene and PCR-base sequence typing of Legionella pneumophila from cooling water systems of two cities in Iran. Virulence 2016; 7:602-9. [PMID: 27028760 DOI: 10.1080/21505594.2016.1170944] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Legionella pneumophila is the primary respiratory pathogen and mostly transmitted to human through water cooling systems and cause mild to severe pneumonia with high mortality rate especially in elderly both in hospitals and community. However, current Legionella risk assessments may be compromised by uncertainties in Legionella detection methods. Here, we investigated the presence of L. pneumophila mip gene in water samples collected from different hospitals cooling towers, nursing homes and building/hotels water coolants from two geographical locations of Iran (Kerman and Bam cities) during summer season of 2015 by both nested and real-time PCR methods. Analysis of the 128 water samples for presence of the mip gene by nested-PCR revealed, 18 (23%) positive cases in Kerman and 7(14%) in Bam. However, when samples were tested by real-time PCR, we identified 4 more new cases of L. pneumophila in the hospitals as well as nursing homes water systems that were missed by nested-PCR. The highest rate of contamination was detected in water obtained from hospitals cooling towers in both the cities (p≤0.05). Dendrogram analysis and clonal relationship by PCR-base sequence typing (SBT) of the L. pneumophila genomic DNAs in Kerman water samples showed close clonal similarities among the isolates, in contrast, isolates identified from Bam city demonstrated two fingerprint patterns. The clones from hospital water samples were more related to the L. pneumophila serogroup- 1.
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Affiliation(s)
- Roya Ahmadrajabi
- a Faculty of Medicine, Microbiology Section, Bam University of Medical Sciences , Bam , Iran
| | - Mohammad Reza Shakibaie
- b Department of Microbiology and Virology , Kerman University of Medical Sciences , Kerman , Iran.,c Environmental Health and Engineering Research Center, Kerman University of Medical Sciences , Kerman , Iran
| | - Zahra Iranmanesh
- b Department of Microbiology and Virology , Kerman University of Medical Sciences , Kerman , Iran
| | - Hamid Reza Mollaei
- b Department of Microbiology and Virology , Kerman University of Medical Sciences , Kerman , Iran
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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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