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. 2024 Aug 31;65(2):E166-E171.
doi: 10.15167/2421-4248/jpmh2024.65.2.3195. eCollection 2024 Jun.

Environmental Surveillance of Legionella spp. in an Italian University Hospital: results of 7 years of analysis

Lucia Massolo  1 , Matilde Ogliastro  1 , Peter Postma  1 , Oriana Ferrante  1 , Rosa Amato  1 , Elvira Massaro  1 , Dorotea Bellina  2 , Roberto Ziferro  2 , Alberto Borneto  3 , Alessandra Morando  4 , Andrea Orsi  1   2
Affiliations

Environmental Surveillance of Legionella spp. in an Italian University Hospital: results of 7 years of analysis

Lucia Massolo et al. J Prev Med Hyg. .

Abstract

Introduction: Nosocomial structures pose a high risk of Legionella spp. contamination due to complex water systems with challenging disinfection; moreover, the risk of severe legionellosis as a consequence of nosocomial exposure is very high in settings characterized by vulnerable patient conditions.

Methods: In the present work, we described the results of 7 years of environmental surveillance in a reference hospital in Liguria, in which a specific water safety plan (WSP) has been implemented in 2017, including data collected during the COVID-19 pandemic.

Results: During the study period, 1190 water samples were collected, of which 277 (23.3%) tested positive for Legionella spp. Positive samples with concentration values above 1,000 CFU/l were 184 (66.4%). Based on the new structure categorization contained in the WSP, hospital buildings classified as at "very high" risk resulted the most affected structures over the entire study period; however, the absolute number of positive samples greatly decreased over time, from 61 contaminated water samples in 2017 to only 9 in 2023.

Conclusions: Our findings prompted the reinforcement of control and prevention measures, affirming the appropriateness of risk-category classification. Indeed, the majority of contamination cases were associated with the water networks of buildings classified as "very high" risk.

Keywords: Hospital surveillance; Legionella; Water safety plan.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1.
Fig. 1.
Prevalence of positive sampling found in the sampling of the hospital water network of the IRCCS San Martino Polyclinic Hospital, Genoa (January 2017-November 2023).
Fig. 2.
Fig. 2.
Prevalence of hospital water network sampling positive results with Legionella spp. concentration above 1,000 UCF/l (January 2017-November 2023).
Fig. 3.
Fig. 3.
Histogram showing the absolute numbers of Legionella pneumophila Ser. 1, Ser. 3, Ser 6 and Ser 2-14 detected in each year of our investigation.
Fig. 4.
Fig. 4.
Prevalence of contamination of the water network of the buildings analyzed in relation to the risk category to which they belong in each year of our survey (January 2017-November 2023).
See this image and copyright information in PMC

References

    1. Barbuti S, Fara GM, Giammanco G. Hygiene − Preventive Medicine − Public Health. EdiSES 2022.
    1. Fraser DW. The challenges were legion. Lancet Infect Dis 2005;5:237-41. https://doi.org/10.1016/S1473-3099(05)70054-2 10.1016/S1473-3099(05)70054-2. - DOI - PubMed
    1. Ministry of Health. Line and guide for the prevention and control of legionellosis (2015). Available at: https://www.salute.gov.it/imgs/C_17_pubblicazioni_2362_allegato.pdf (Accessed on: 09/09/2023).
    1. Diederen BM. Legionella spp. and Legionnaires’ disease. J Infect 2008;56:1-2. https://doi.org/10.1016/j.jinf.2007.09.010 10.1016/j.jinf.2007.09.010. - DOI - PubMed
    1. Cunha BA, Burillo A, Bouza E. Legionnaires’ disease. Lancet 2016;387:376-85. https://doi.org/10.1016/S0140-6736(15)60078-2 10.1016/S0140-6736(15)60078-2. - DOI - PubMed

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