How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience
Abstract
:1. Introduction
2. Materials and Methods
2.1. Hospital Characteristics
2.2. Hot Water Network Disinfection Treatment
2.3. Sample Collection
2.4. Microbiological Analysis
2.5. Serological Identification
2.6. SBT Typing and Sequencing
2.7. mip Gene Sequencing
2.8. Phylogenetic and Allelic Diversity Analysis
2.9. Statistical Analysis
3. Results
3.1. Microbiological, Physical, and Chemical Results
3.2. Legionella Serotyping and Genotyping Results
3.3. Legionella Contamination in the Hospital
3.4. Correlation between Legionella and Physical–Chemical Parameters
4. Discussion
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
- Bianchi, A.; Pregliasco, F.; Consonni, M.; Tesauro, M.; Galli, M.G. New sequence types of Legionella pneumophila circulating in northern Italy and comparison with other regions of the world. J. Hosp. Infect. 2010, 76, 365–367. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Tesauro, M.; Bianchi, A.; Consonni, M.; Pregliasco, F.; Galli, M.G. Environmental surveillance of Legionella pneumophila in two Italian hospitals. Ann. Dell’Istituto Super Sanità 2010, 46, 274–278. [Google Scholar] [CrossRef]
- Papadakis, A.; Chochlakis, D.; Sandalakis, V.; Keramarou, M.; Tselentis, Y.; Psaroulaki, A. Legionella spp. Risk assessment in recreational and garden areas of hotels. Int. J. Environ. Res. Public Health 2018, 15, 598. [Google Scholar] [CrossRef] [Green Version]
- Centers for Disease Control and Prevention (CDC) Legionella (Legionnaires’ Disease and Pontiac Fever). Available online: https://www.cdc.gov/legionella/clinicians/diagnostic-testing.html (accessed on 25 September 2020).
- Rota, M.C.; Caporali, M.G.; Bella, A.; Scaturro, M.; Giannitelli, S.; Ricci, M.L. Annual Report of Legionellosis in Italy—2018. Available online: http://www.legionellaonline.it/Not%20ISS%20nov%202019.pdf (accessed on 30 August 2020).
- Italian Health Ministry. Guidelines for Prevention and Control of Legionellosis; Approvate in Conferenza Stato-Regioni Seduta Del 7 Maggio 2015; Italian Health Ministry: Rome, Italy, 2015.
- Mancini, B.; Scurti, M.; Dormi, A.; Grottola, A.; Zanotti, A.; Cristino, S. Effect of monochloramine treatment on colonization of a hospital water distribution system by Legionella spp.: A 1 year experience study. Environ. Sci. Technol. 2015, 49, 4551–4558. [Google Scholar] [CrossRef]
- Pancer, K. Sequence-based typing of Legionella pneumophila strains isolated from hospital water distribution systems as a complementary element of risk assessment of legionellosis in Poland. Ann. Agric. Environ. Med. 2013, 20, 436–440. [Google Scholar]
- Cunliffe, D.; Bartram, J.; Briand, E.; Chartier, Y.; Colbourne, J.; Drury, D.; Lee, J.; Schaefer, B.; Surman-Lee, S.; WHO. Water Safety in Buildings; World Health Organization: Geneva, Switzerland, 2011; ISBN 9789241548106. [Google Scholar]
- Chasqueira, M.J.; Rodrigues, L.; Nascimento, M.; Marques, T. Sequence-based and monoclonal antibody typing of Legionella pneumophila isolated from patients in Portugal during 1987–2008. Eurosurveillance 2009, 14, 19271. [Google Scholar] [CrossRef] [Green Version]
- Scaturro, M.; Losardo, M.; De Ponte, G.; Ricci, M.L. Comparison of three molecular methods used for subtyping of Legionella pneumophila strains isolated during an epidemic of legionellosis in Rome. J. Clin. Microbiol. 2005, 43, 5348–5350. [Google Scholar] [CrossRef] [Green Version]
- Katsiaflaka, A.; Pournaras, S.; Kristo, I.; Mouchtouri, V.A.; Kyritsi, M.; Velonakis, E.; Vatopoulos, A.C.; Hadjichristodoulou, C. Epidemiological Investigation of Legionella pneumophila Serogroup 2 to 14 Isolates from Water Samples by Amplified Fragment Length Polymorphism and Sequence-Based Typing and Detection of Virulence Traits. Appl. Environ. Microbiol. 2016, 82, 6102–6108. [Google Scholar] [CrossRef]
- Enright, M.; Spratt, B. A multilocus sequence typing scheme for Streptococcus pneumoniae: Identification of clones associated with serious invasive disease. Microbiology 1998, 144, 3049–3060. [Google Scholar] [CrossRef] [Green Version]
- Gaia, V.; Fry, N.K.; Harrison, T.G.; Peduzzi, R. The Potential for True Portability in Legionellosis Outbreak Investigation. Society 2003, 41, 2932–2939. [Google Scholar] [CrossRef]
- Shuval, H.; Yarom, R.; Shenman, R. An Innovative Method for the Control of Legionella Infections in the Hospital Hot Water Systems with a Stabilized Hydrogen Peroxide-Silver Formulation. Int. J. Infect. Control 2009, 5. [Google Scholar] [CrossRef]
- Burillo, A.; Pedro-Botet, M.L.; Bouza, E. Microbiology and Epidemiology of Legionnaire’s Disease. Infect. Dis. Clin. N. Am. 2017, 31, 7–27. [Google Scholar] [CrossRef]
- Fry, N.K.; Afshar, B.; Bellamy, W.; Underwood, A.P.; Ratcliff, R.M.; Harrison, T.G.; Bangsborg, J.; Blanco, S.; Etienne, J.; Fendukly, F.; et al. Identification of Legionella spp. by 19 European reference laboratories: Results of the European Working Group for Legionella Infections External Quality Assessment Scheme using DNA sequencing of the macrophage infectivity potentiator gene and dedi. Clin. Microbiol. Infect. 2007, 13, 1119–1124. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- D.Lgs.31. Legislative Decree 02.02.2001, n.31. Implementation of theWater Quality Directive 98/83/EC Relative to Water Quality Intended for Human Consumption. OJ. of the Italian Republic n. 52, 3.03.2001. Available online: http://www.camera.it/parlam/leggi/deleghe/01031dl.htm (accessed on 30 August 2020).
- Council of the European Union. Regulation (EU) No 528/2012 of the European Parliament and of the Council of 22 May 2012 Concerning the Making Available on the Market and Use of Biocide Products; Council of the European Union: Brussels, Belgium, 2012; pp. 1–123. [Google Scholar]
- Council of the European Union. European Council Directive 98/83/EC of 3 November 1998 on the Quality ofWater Intended for Human Consumption; Council of the European Union: Brussels, Belgium, 1998; pp. 32–54. [Google Scholar]
- Imlay, J. The molecular mechanisms and physiological consequences of oxidative stress: Lessons from a model bacterium. Nat. Rev. Microbiol. 2013, 11, 443–454. [Google Scholar] [CrossRef] [Green Version]
- Vatansever, F.; de Melo, W.C.M.A.; Avci, P.; Vecchio, D.; Sadasivam, M.; Gupta, A.; Chandran, R.; Karimi, M.; Parizotto, N.A.; Yin, R.; et al. Antimicrobial strategies centered around reactive oxygen specie—bactericidal antibiotics, photodynamic therapy, and beyond. FEMS Microbiol. Rev. 2013, 37, 955–989. [Google Scholar] [CrossRef] [Green Version]
- UNI EN ISO 19458:2006—Water Quality—Sampling for Microbiological Analysis. Available online: http://store.uni.com/catalogo/index.php/unieniso194582006.html?josso_back_to=http://store.uni.com/josso-securitycheck.php&josso_cmd=login_optional&josso_partnerapp_host=store.uni.com (accessed on 30 August 2020).
- ISO. ISO 11731:2017 Water Quality—Enumeration of Legionella 2017; ISO: Geneva, Switzerland, 2017; Available online: https://www.iso.org/standard/61782.html (accessed on 30 August 2020).
- Hutchinson, E.J.; Joseph, C.; Bartlett, C.L. A European surveillance scheme for travel associated legionnaires disease. Euro Surveill. 1996, 1, 33–39. [Google Scholar] [CrossRef]
- Ratcliff, R.M.; Lanser, J.A.; Manning, P.A.; Heuzenroeder, M.W. Sequence-based classification scheme for the genus Legionella targeting the mip gene. J. Clin. Microbiol. 1998, 36, 1560–1567. [Google Scholar] [CrossRef] [Green Version]
- Mentasti, M.; Fry, N.K.; Afshar, B.; Palepou-Foxley, C.; Naik, F.C.; Harrison, T.G. Application of Legionella pneumophila-specific quantitative real-time PCR combined with direct amplification and sequence-based typing in the diagnosis and epidemiological investigation of Legionnaires’ disease. Eur. J. Clin. Microbiol. Infect. Dis. 2012, 31, 2017–2028. [Google Scholar] [CrossRef]
- Kearse, M.; Moir, R.; Wilson, A.; Stones-Havas, S.; Cheung, M.; Sturrock, S.; Buxton, S.; Cooper, A.; Markowitz, S.; Duran, C.; et al. Geneious Basic: An integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics 2012, 28, 1647–1649. [Google Scholar] [CrossRef]
- Price, M.N.; Dehal, P.S.; Arkin, A.P. FastTree 2—Approximately maximum-likelihood trees for large alignments. PLoS ONE 2010, 5, e9490. [Google Scholar] [CrossRef]
- Fontana, S.; Scaturro, M.; Rota, M.C.; Caporali, M.G.; Ricci, M.L. Molecular typing of Legionella pneumophila serogroup 1 clinical strains isolated in Italy. Int. J. Med. Microbiol. 2014, 304, 597–602. [Google Scholar] [CrossRef] [PubMed]
- Ohno, A.; Kato, N.; Yamada, K.; Yamaguchi, K. Factors Influencing Survival of Legionella pneumophila Serotype 1 in Hot Spring Water and Tap Water. Appl. Environ. Microbiol. Environ. Microbiol. 2003, 69, 2540–2547. [Google Scholar] [CrossRef]
- Shih, H.Y.; Lin, Y.E. Caution on interpretation of Legionella results obtained using real-time PCR for environmental water samples. Appl. Environ. Microbiol. 2006, 72, 6859. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Whiley, H.; Taylor, M. Legionella detection by culture and qPCR: Comparing apples and oranges. Crit. Rev. Microbiol. 2014, 42, 65–74. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Lévesque, S.; Lalancette, C.; Bernard, K.; Pacheco, A.L.; Dion, R.; Longtin, J.; Tremblay, C. Molecular typing of Legionella pneumophila isolates in the province of Quebec from 2005 to 2015. PLoS ONE 2016, 11, e0163818. [Google Scholar] [CrossRef]
- Girolamini, L.; Dormi, A.; Pellati, T.; Somaroli, P.; Montanari, D.; Costa, A.; Savelli, F.; Martelli, A.; Grottola, A.; Fregni Serpini, G.; et al. Advances in Legionella control by a new formulation of hydrogen peroxide and silver salts in a hospital hot water network. Pathogens 2019, 8, 209. [Google Scholar] [CrossRef] [Green Version]
- Gamage, S.D.; Ambrose, M.; Kralovic, S.M.; Roselle, G.A. Water Safety and Legionella in Health Care: Priorities, Policy, and Practice. Infect. Dis. Clin. N. Am. 2016, 30, 689–712. [Google Scholar] [CrossRef]
- Gomez-Valero, L.; Rusniok, C.; Buchrieser, C. Legionella pneumophila: Population genetics, phylogeny and genomics. Infect. Genet. Evol. 2009, 9, 727–739. [Google Scholar] [CrossRef]
- Vaccaro, L.; Izquierdo, F.; Magnet, A.; Hurtado, C.; Salinas, M.A.; Gomes, T.S.; Angulo, S.; Salso, S.; Pelaez, J.; Tejeda, M.I.; et al. First case of legionnaire’s disease caused by Legionella anisa in Spain and the limitations on the diagnosis of Legionella non-pneumophila infections. PLoS ONE 2016, 11, e0159726. [Google Scholar] [CrossRef]
- Compain, F.; Bruneval, P.; Jarraud, S.; Perrot, S.; Aubert, S.; Napoly, V.; Ramahefasolo, A.; Mainardi, J.L.; Podglajen, I. Chronic endocarditis due to Legionella anisa: A first case difficult to diagnose. New Microbes New Infect. 2015, 8, 113–115. [Google Scholar] [CrossRef] [Green Version]
- Head, B.M.; Trajtman, A.; Bernard, K.; Burdz, T.; Vélez, L.; Herrera, M.; Rueda, Z.V.; Keynan, Y. Legionella co-infection in HIV-associated pneumonia. Diagn. Microbiol. Infect. Dis. 2019, 95, 71–76. [Google Scholar] [CrossRef] [PubMed]
- Matsui, M.; Fujii, S.I.; Shiroiwa, R.; Amemura-Maekawa, J.; Chang, B.; Kura, F.; Yamauchi, K. Isolation of Legionella rubrilucens from a pneumonia patient co-infected with Legionella pneumophila. J. Med. Microbiol. 2010, 59, 1242–1246. [Google Scholar] [CrossRef] [PubMed]
- Van Der Mee-Marquet, N.; Domelier, A.S.; Arnault, L.; Bloc, D.; Laudat, P.; Hartemann, P.; Quentin, R. Legionella anisa, a possible indicator of water contamination by Legionella pneumophila. J. Clin. Microbiol. 2006, 44, 56–59. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Boppe, I.; Bédard, E.; Taillandier, C.; Lecellier, D.; Nantel-Gauvin, M.A.; Villion, M.; Laferrière, C.; Prévost, M. Investigative approach to improve hot water system hydraulics through temperature monitoring to reduce building environmental quality hazard associated to Legionella. Build. Environ. 2016, 108, 230–239. [Google Scholar] [CrossRef] [Green Version]
- 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. [Google Scholar] [CrossRef]
- Lesnik, R.; Brettar, I.; Höfle, M.G. Legionella species diversity and dynamics from surface reservoir to tap water: From cold adaptation to thermophily. ISME J. 2016, 10, 1064–1080. [Google Scholar] [CrossRef] [Green Version]
- Graham, F.F.; Hales, S.; White, P.S.; Baker, M.G. Review Global seroprevalence of legionellosis—A systematic review and meta-analysis. Sci. Rep. 2020, 10, 1–11. [Google Scholar] [CrossRef]
Hospital Outlet Distribution | |||||||||||
Sample ID | Sample Point | Location | |||||||||
56 | Aqueduct | Technical room | |||||||||
64 | Tap water output | Technical room | |||||||||
Building A outlet distribution | Building B outlet distribution | Building C outlet distribution | |||||||||
Sample ID | Sample Point | Floor | Location | Sample ID | Sample Point | Floor | Location | Sample ID | Sample Point | Floor | Location |
1a | Hot water return line building A | - | Technical room | 1b | Hot water return line building B | - | Technical room | 1c | Hot water return line building C | - | Technical room |
1 | Service | 0 | near | 22 | Service | −1 | 43 | Service | −1 | near | |
2 | Common area | 0 | intermediate | 23 | Common area | 0 | near | 44 | Service | −1 | far |
3 | Common area | 0 | far | 24 | Service | 0 | intermediate | 45 | Common area | 0 | near |
4 | Common area | 0 | far | 25 | Common area | 0 | intermediate | 46 | Service | 0 | far |
5 | Common area | 1 | near | 26 | Service | 0 | far | 47 | Service | 1 | near |
6 | Common area | 1 | intermediate | 27 | Operating room | 0 | far | 48 | Service | 1 | far |
7 | Service | 1 | far | 28 | Inpatient rooms | 1 | near | 49 | Common area | 2 | near |
8 | Common area | 1 | far | 29 | Service | 1 | intermediate | 50 | Inpatient rooms | 3 | near |
9 | Inpatient rooms | 2 | near | 30 | Inpatient rooms | 1 | intermediate | 51 | Inpatient rooms | 3 | intermediate |
10 | Service | 2 | intermediate | 31 | Inpatient rooms | 1 | far | 52 | Inpatient rooms | 3 | far |
11 | Inpatient rooms | 2 | far | 32 | Common area | 1 | far | 53 | Inpatient rooms | 4 | near |
12 | Operating room | 2 | far | 33 | Inpatient rooms | 2 | near | 54 | Inpatient rooms | 4 | intermediate |
13 | Operating room | 2 | far | 34 | Inpatient rooms | 2 | intermediate | 55 | Inpatient rooms | 4 | far |
14 | Intensive care | 4 | near | 35 | Service | 2 | intermediate | ||||
15 | Intensive care | 4 | intermediate | 36 | Inpatient rooms | 2 | far | ||||
16 | Intensive care | 4 | far | 37 | Inpatient rooms | 2 | far | ||||
17 | Common area | 4 | far | 38 | Inpatient rooms | 3 | near | ||||
18 | Operating room | 5 | near | 39 | Inpatient rooms | 3 | intermediate | ||||
19 | Common area | 5 | intermediate | 40 | Inpatient rooms | 3 | far | ||||
20 | Operating room | 5 | far | 41 | Inpatient rooms | 4 | near | ||||
21 | Operating room | 5 | far | 42 | Service | 4 | far |
Legionella Species Isolated | Building Comparisons | Kruskal–Wallis Test p-Values | Type of Comparison | Mann–Whitney Test p-Values |
---|---|---|---|---|
Total Legionella | A ≠ B | 2 × 10−11 | A > B | 3.26 × 10−12 * |
A ≠ C | 6.32 × 10−3 | A > C | 3.16 × 10−3 * | |
B ≠ C | 2.20 × 10−4 | B < C | 7.45 × 10−5 * | |
L. pneumophila (SG1) | A ≠ B | 2.60 × 10−5 | A > B | 4.36 × 10−6 * |
A ≠ C | 0.535 | |||
B ≠ C | 2.00 × 10−3 | B < C | 6.71 × 10−4 * | |
Non-pneumophila Legionella species | A ≠ B | 5.10 × 10−10 | A > B | 8.56 × 10−11 * |
A ≠ C | 1.60 × 10−3 | A > C | 5.27 × 10−4 * | |
B ≠ C | 8.50 × 10−3 | B < C | 4.27 × 10−3 * |
Building | Legionella Comparison | Mann–Whitney Test p-Value | Legionella Comparison | Mann–Whitney Test p-Value |
---|---|---|---|---|
Hospital complex | L. pneumophila ≠ non-pneumophila Legionella species | 0.011 * | L. pneumophila > non-pneumophila Legionella species | 5.67 × 10−3 * |
A | L. pneumophila ≠ non-pneumophila Legionella species | 0.64 | ||
B | L. pneumophila ≠ non-pneumophila Legionella species | 0.027 * | L. pneumophila > non-pneumophila Legionella species | 0.014 * |
C | L. pneumophila ≠ non-pneumophila Legionella species | 5.70 × 10−3 * | L. pneumophila > non-pneumophila Legionella species | 2.90 × 10−3 * |
Building | Sample Contamination | Number of Positive Samples, n (%) | Legionella Contamination, Mean ± SD (Log CFU/L) | Temperature, Mean ± SD (Minimum–Maximum) (°C) | H2O2 Residues, Mean ± SD (Min–Max) (mg/L) |
---|---|---|---|---|---|
Hospital complex | Total Legionella | 191/307 (62.21%) | 3562.43 ± 20,648.43 | 49.36 ± 2.61 (32.5–65.0) | 12.24 ± 5.18 (0–25) |
Only L. pneumophila (SG1) | 67/191 (35.08%) | 1457.06 ± 12,969.76 | |||
Only non-pneumophila Legionella species | 41/191 (21.47%) | 132.87 ± 584.01 | |||
Both species | 83/191 (43.46%) | 4136.19 ± 22,787.28 | |||
A | Total Legionella | 102/127 (80.31%) | 7434.23 ± 31,459.66 | 49.16 ± 2.49 (33.27–54.10) | 13.23 ± 4.84 (1.00–25.00) |
Only L. pneumophila (SG1) | 26/102 (25.49%) | 2550.13 ± 17,709.16 | |||
Only non-pneumophila Legionella species | 26/102 (25.49%) | 229.60 ± 783.67 | |||
Both species | 50/102 (49.02%) | 6476.85 ± 30,675.22 | |||
B | Total Legionella | 48/122 (39.34%) | 1066.80 ± 4520.13 | 49.40 ± 2.48 (39.85–65.00) | 11.85 ± 4.56 (0–25.00) |
Only L. pneumophila (SG1) | 23/48 (47.92%) | 153.75 ± 340.35 | |||
Only non-pneumophila Legionella species | 9/48 (18.75%) | 11.64 ± 39.15 | |||
Both species | 16/48 (33.33%) | 2546.06 ± 6985.17 | |||
C | Total Legionella | 41/58 (70.69%) | 333.93 ± 613.4 | 49.72 ± 3.07 (32.50–57.00) | 10.89 ± 6.60 (0–22.50) |
Only L. pneumophila (SG1) | 18/41 (43.90%) | 263.54 ± 679.57 | |||
Only non-pneumophila Legionella species | 6/41 (14.63%) | 34.15 ± 126.99 | |||
Both species | 17/41 (41.46%) | 174.70 ± 340.95 |
Building | Legionella Comparisons | Mann–Whitney Test p–Value | Legionella Comparisons | Mann–Whitney Test p-Value |
---|---|---|---|---|
Hospital complex | Both species ≠ only L. pneumophila | 7.48 × 10−3 * | Both species > only L. pneumophila | 3.74 × 10−3 * |
Both species ≠ only non-pneumophila Legionella species | 4.28 × 10−8 * | Both species > only non-pneumophila Legionella species | 2.14 × 10−8 * | |
only L. pneumophila ≠ only non-pneumophila Legionella species | 1.54 × 10−3 * | Only L. pneumophila > only non-pneumophila Legionella species | 7.71 × 10−4 * | |
A | Both species ≠ only L. pneumophila | 1.95 × 10−4 * | Both species > only L. pneumophila | 9.74 × 10−5 * |
Both species ≠ only non-pneumophila Legionella species | 3.47 × 10−5 * | Both species > only non-pneumophila Legionella species | 1.74 × 10−5 * | |
only L. pneumophila ≠ only non-pneumophila Legionella species | 0.8696 | |||
B | Both species ≠ only L. pneumophila | 0.6593 | ||
Both species ≠ only non-pneumophila Legionella species | 0.03 * | Both species > only non-pneumophila Legionella species | 0.015 * | |
only L. pneumophila ≠ only non-pneumophila Legionella species | 8.07 × 10−4 * | Only L. pneumophila > only non-pneumophila Legionella species | 0.015 * | |
C | Both species ≠ only L. pneumophila | 0.97 | ||
Both species ≠ only non-pneumophila Legionella species | 3.70 × 10−3 * | Both species > only non-pneumophila Legionella species | 1.85 × 10−3 * | |
only L. pneumophila ≠ only non-pneumophila Legionella species | 2.75 × 10−3 * | only L. pneumophila > only non-pneumophila Legionella species | 1.85 × 10−3 * |
Building | L. Pneumophila vs. Non-Pneumophila Legionella Species | L. Pneumophila vs. Temperature | L. Pneumophila vs. Disinfectant | Non-Pneumophila Legionella Species vs. Temperature | Non-Pneumophila Legionella Species vs. Disinfectant |
---|---|---|---|---|---|
Hospital complex | rs = 0.33 p = 1 × 10−5 * | rs = −0.29 p = 1 × 10−5 * | rs = −0.20 p = 4 × 10−4 * | rs = −0.33 p = 1 × 10−5 * | rs = −0.07 p = 0.22 |
A | rs = 0.19 p = 0.031 * | rs = −0.36 p = 1 × 10−5 * | rs = −0.10 p = 0.25 | rs = −0.45 p = 1 × 10−5 * | rs = −0.096 p = 0.28 |
B | rs = 0.42 p = 1 × 10−5 * | rs = −0.27 p = 2.80 × 10−3 * | rs = −0.35 p = 1 × 10−5 * | rs = −0.28 p = 2.10 × 10−3 * | rs = −0.14 p = 0.12 |
C | rs = 0.14 p = 0.31 | rs = −0.35 p = 6.50 × 10−3 * | rs = −0.24 p = 0.075 | rs = −0.30 p = 0.024 * | rs = −0.15 p = 0.25 |
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Girolamini, L.; Salaris, S.; Lizzadro, J.; Mazzotta, M.; Pascale, M.R.; Pellati, T.; Cristino, S. How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience. Int. J. Environ. Res. Public Health 2020, 17, 8662. https://doi.org/10.3390/ijerph17228662
Girolamini L, Salaris S, Lizzadro J, Mazzotta M, Pascale MR, Pellati T, Cristino S. How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience. International Journal of Environmental Research and Public Health. 2020; 17(22):8662. https://doi.org/10.3390/ijerph17228662
Chicago/Turabian StyleGirolamini, Luna, Silvano Salaris, Jessica Lizzadro, Marta Mazzotta, Maria Rosaria Pascale, Tiziana Pellati, and Sandra Cristino. 2020. "How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience" International Journal of Environmental Research and Public Health 17, no. 22: 8662. https://doi.org/10.3390/ijerph17228662