Geostatistics – a tool applied to the distribution of Legionella pneumophila in a hospital water system
More details
Hide details
Department of Biomedical and Dental Sciences and Morphofunctional Imaging. Section of Biotechnologies and Medicine Preventive. University of Messina, Italy
Department of Public Health – Università Cattolica del Sacro Cuore – Rome, Italy
Ann Agric Environ Med. 2015;22(4):655-660
Legionnaires’ disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large buildings, such as hospitals, are often contaminated with legionellae and therefore represent a potential risk for the hospital population. The aim of this study was to evaluate the potential contamination of Legionella pneumophila (LP) in a large hospital in Italy through georeferential statistical analysis to assess the possible sources of dispersion and, consequently, the risk of exposure for both health care staff and patients.

Material and Methods:
LP serogroups 1 and 2–14 distribution was considered in the wards housed on two consecutive floors of the hospital building. On the basis of information provided by 53 bacteriological analysis, a ‘random’ grid of points was chosen and spatial geostatistics or FAIk Kriging was applied and compared with the results of classical statistical analysis.

Over 50% of the examined samples were positive for Legionella pneumophila. LP 1 was isolated in 69% of samples from the ground floor and in 60% of sample from the first floor; LP 2–14 in 36% of sample from the ground floor and 24% from the first. The iso-estimation maps show clearly the most contaminated pipe and the difference in the diffusion of the different L. pneumophila serogroups.

Experimental work has demonstrated that geostatistical methods applied to the microbiological analysis of water matrices allows a better modeling of the phenomenon under study, a greater potential for risk management and a greater choice of methods of prevention and environmental recovery to be put in place with respect to the classical statistical analysis.

Kool JL, Bergmire-Sweat D, Butler JC, Brown EW, Peabody DJ, Massi DS, et al. Hospital characteristics associated with colonization of water systems by Legionella and risk of nosocomial legionnaires’ disease: a cohort study of 15 hospitals. Infect Control Hosp Epidemiol. 1999; 20: 798–805.
Rudbeck M, Viskum S, Mølbak K, Uldum SA. Legionella antibodies in a Danish hospital staff with known occupational exposure. J Environ Public Health. 2009: 812829.
Delia S, Merlino G, Mauro A, Laganà P. L. pneumophila in a hospital environment. Preliminary results. Riv Ital Igiene 1990; 50: 54–67.
Delia S, Merlino G, Laganà P. L. pneumophila in a hospital environment. Final results. Riv Ital Igiene 1991; 51: 143–150.
Delia S, Laganà P. Environmental research of L. pneumophila at the Polyclinic of Messina. Riv Ital Igiene 1995; 55: 149–156.
Delia S, Laganà P. Unusual sources of L. pneumophila in a hospital environment. Annali di Igiene e Med. Prev. e di Comunità 2002; 14: 443–6.
Angelbeck JA, Ortolano GA, Canonica FP, Cervia JS. Hospital water. A source of concern for infections. Manag Infect Control. 2006; 6: 44–54.
Kusnetsov J, Torvinen E, Perola O, Nousiainen T, Katila ML. Colonization of hospital water systems by Legionellae, mycobacteria and other heterotrophic bacteria potentially hazardous to risk group patients. Acta Pathol Microbiol Immunol Scand. 2003; 111: 546–556.
Anaissie EJ, Penzak SR, Dignani MC. The hospital water supply as a source of nosocomial infections: a plea for action. Arch Intern Med. 2002; 162: 1483–1492.
Osawa K, Shigemura K, Abe Y, Jikimoto T, Yoshida H, Fujisawa M, Arakawa S. A case of nosocomial Legionella pneumonia associated with a contaminated hospital cooling tower. J Infect Chemother. 2014 Jan; 20(1): 6.
Røysted W, Simonsen Ø, Jenkins A, Sarjomaa M, Svendsen MV, Ragnhildstveit E, Tveten Y, Kanestrøm A, Waage H, Ringstad J. Etiology and risk factors of community-acquired pneumonia in hospitalized patients in Norway. Clin Respir J. 2015 Mar 12.
Fard SY, Nomanpour B, Fatolahzadeh B, Mobarez AM, Darban-Sarokhalil D, Fooladi AA et al. Hospital acquired pneumonia: comparison of culture and real-time PCR assays for detection of Legionella pneumophila from respiratory specimens at Tehran Hospitals. Acta Microbiol Immunol Hung. 2012 Sep; 59(3): 355–65.
Mekkour M, Ben Driss E, Tai J, Squinazi F, Forey F, Jarraud S, Cohen N. Molecular typing of Legionella pneumophila strains isolated from environment in Morocco. Cell Mol Biol. (Noisy-le-grand). 2012 Jun 30; 58 Suppl: OL1709–14.
Mérault N, Rusniok C, Jarraud S, Gomez-Valero L, Cazalet C, Marin M, et al. Specific real-time PCR for simultaneous detection and identification of Legionella pneumophila serogroup 1 in water and clinical samples. Appl Environ Microbiol. 2011 Mar;77(5): 1708–17.
Knirsch CA, Jakob K, Schoonmaker D, Kiehlbauch JA, Wong SJ, Della-Latta P, et al. An outbreak of Legionella micdadei pneumonia in transplant patients: evaluation, molecular epidemiology, and control. Am J Med. 2000 Mar; 108(4): 290–5.
Wellinghausen N, Frost C and Marre R. Detection of Legionellae in Hospital Water Samples by Quantitative Real-Time LightCycler PCR. Applied Environ Microbiol. 2001; p. 3985–3993.
Cordes LG, Wiesenthal AM, Gorman GW, Phair JP, Sommers HM, Brown A, et al. Isolation of Legionella pneumophila from hospital shower heads. Ann Intern Med. 1981; 94: 195–197.
Goetz AM, Stout JE, Jacobs SL, Fisher MA, Ponzer RE, Drenning S, et al. Nosocomial legionnaires’ disease discovered in community hospitals following cultures of the water system: seek and ye shall find. Am J Infect Control. 1998; 26: 8–11.
Laganà P, Delia S. Environmental sources of Legionella pneumophila: incubators in a Premature Unit. J Prev Med Hyg. 2000; 41: 34–36.
Leoni E, De Luca G, Legnani PP, Sacchetti R, Stampi S, Zanetti F. Legionella waterline colonization: detection of Legionella species in domestic, hotel and hospital hot water systems. J Appl Microbiol. 2005; 98: 373–379.
Perola O, Kauppinen J, Kusnetsov J, Heikkinen J, Jokinen C, Katila ML. Nosocomial Legionella pneumophila serogroup 5 outbreak associated with persistent colonization of a hospital water system. Acta Pathol Microbiol Immunol Scand. 2002; 110: 863–868.
Stojek NM, Szymanska J, Dutkiewicz J. Gram-negative bacteria in water distribution systems of hospitals. Ann Agric Environ Med. 2008; 15: 135–142.
Boccia S, Laurenti P, Borella P, Moscato U, Capalbo G, Cambieri A, et al. Prospective three year surveillance for nosocomial and environmental Legionella: implications for infection control. Infect Control Hosp Epidemiol. 2006; 27: 459–465.
Ditommaso S, Giacomuzzi M, Biasin C, Gentile M, Maggiorotto G, Ruggenini Moiraghi A et al. Legionellosis Collaborating Group.Incidence of Legionellosis in hospitals contaminated by Legionella pneumophila other than serogroup 1. Infect Control Hosp Epidemiol. 2007; 28: 509–511.
Ditommaso S, Giacomuzzi M, Rivera SR, Raso R, Ferrero P, Zotti CM. Virulence of Legionella pneumophila strains isolated from hospital water system and healthcare-associated Legionnaires’ disease in Northern Italy between 2004 and 2009. BMC Infect Dis. 2014 Sep 5; 14: 483.
Laurenti P, Quaranta G, Branca G, Tumbarello M, Capoluongo E, Orsini M, et al. Epidemiological monitoring of legionellosis: a case-control study in an university general hospital. Ig Sanità Pubbl. 2003; 59: 203–214.
Pignato S, Coniglio MA, Faro G, Cantaro P, Carini SA, Mangano G, et al. Legionella contamination in the hospital environment. Monitoring of the hot water distribution systems of three hospitals in Catania (Italy). Ig Sanità Pubbl. 2006; 62: 635–652.
Triassi M, Di Popolo A, Ribera D’Alcalà G, Albanese Z, Cuccurullo S, Montegrosso S, et al. Clinical and environmental distribution of Legionella pneumophila in a university hospital in Italy: efficacy of ultraviolet disinfection. J Hosp Infect. 2006; 62: 494–501.
Rota MC, Caporali MG, Napoli C, Bella A, Giannitelli S, Mandarino G, et al. Rapporto annuale sulla legionellosi in Italia nel 2011. Notiz. Ist. Super. Sanità 2012; 25: 17–23.
Fields BS. Legionella in the environment. In: Hoffman P, Friedman H, Bendinelli M. Legionella pneumophila. Pathogenesis and Immunity. New York, Springer, 2007.p.85–94.
Liu WK, Healing DE, Yeomans JT, Elliot TS. Monitoring of hospital water supplies for Legionella. J Hosp Infect. 1993; 24: 1–9.
Marchesi I, Marchegiano P, Bargellini A, Cencetti S, Frezza G, Miselli M, et al. Effectiveness of different methods to control Legionella in the water supply: ten-year experience in an Italian university hospital. J Hosp Infect. 2011; 77: 47–51.
Montagna MT, Napoli C, Tatò D, Spilotros G, Barbuti G, Barbuti S, et al. Clinical-environmental surveillance of legionellosis: an experience in Southern Italy. Eur J Epidemiol. 2006; 21: 325–331.
O’Neill E, Humphreysa H. Surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence? J Hosp Infect. 2005; 59: 273–279.
Bédard E, Fey S, Charron D, Lalancette C, Cantin P, Dolcé P, Laferrière C, Déziel E, Prévost M. Temperature diagnostic to identify high risk areas and optimize Legionella pneumophila surveillance in hot water distribution systems. Water Res. 2015 Mar 15; 71: 244–56.
Laganà P, Caruso G, Piccione D, Gioffrè ME, Pino R, Delia S. Legionella spp., amoebae and not-fermenting Gram negative bacteria in an Italian university hospital water system. Ann Agric Environ Med. 2014; 21(3): 489–93.
Rohuani S, Wackernagel H. Multivariate geostatistical approach to space-time data analysis. ater Resources Research. 1990; 26(4): 585–91.
Raspa G, Bruno R. Papers on Applied Geostatistics. Comett Workshop “Geostatistics for Environment”, 1995: Rome.
Capelli G, Moscato U, Sturniolo A et Al.. Assessment of Thermal Discomfort in a Hospital Ward: a Geostatistical Approach. In: Yoshizawa S, Kimura K, Ikeda K, Tanabe S, Iwata T (eds.). Indoor Air ‘96. “The 7 th International Conference on Indoor Air Quality and Climate”. Proceedings of the 7 th International Conference on Indoor Air Quality and Climate. Nagoya (Japan), 21–26 July 1996. Nagoya 1996, 589–594.
PannatierY. Variowin 2.1 – User’guide Institute of Mineralogy, University of Lausanne, 1994, Switzerland.
Bruno R, Raspa G. The practice of linear geostatistics. Guerini Studio, Milano 1994.
Poscia A, Tuti F, Di Donato M, et al. Air particulate monitoring and geostatistical analysis: a new approach to risk assessment in clean room. In: Proceedings of The 2nd joint European Public Health Conference. 2009. Eur J Public Health, p209.
Moscato U, Canonaco D, Porcelli D, de Belvis AG. Benzene, Toluene and Xylenes pollution: a geostatistical method to assess spatial distribution of BTX and citizens exposure. ISEE/ISEA Joint Conference. Boston MA, 15–19 August 1998. Epidemiology 1998; 9(4): p. 290.
Moscato U, La Torre G, La Torre F et al. Aromatic hydrocarbons outdoor and indoor pollution in Rome. Proceedings of The 66h International Symposium on Advanced Environmental Monitoring. June 27–30, 2006, Heidelberg, Germany.
Moscato U, La Pietra L, Ricciardi G. Polveri e Cantieri in ospedale. Atti del XXXIV Corso Cantieri in Ospedale Erice, Sicilia, 3–6 Marzo 2007. Annali di Igiene 2007; 19 s1 al N.5. Settembre –Ottobre: 173-191.
Journals System - logo
Scroll to top