Background. In this study we estimated the presence of Legionella species, viable but non-culturable (VBNC), in hospital water networks. We also evaluated the time and load of Legionella appearance in samples found negative using the standard culture method. Methods. A total of 42 samples was obtained from the tap water of five hospital buildings. The samples were tested for Legionella by the standard culture method and were monitored for up to 12 months for the appearance of VBNC Legionella. Results. All the 42 samples were negative at the time of collection. Seven of the 42 samples (17.0%) became positive for Legionella at different times of monitoring. The time to the appearance of VBNC Legionella was extremely variable, from 15 days to 9 months from sampling. The most frequent Legionella species observed were Legionella spp and L. anisa and only in one sample L. pneumophila srg.1. Conclusion. Our study confirms the presence of VBNC Legionella in samples resulting negative using the standard culture method and highlights the different time to its appearance that can occur several months after sampling. The results are important for risk assessment and risk management of engineered water systems.

Evaluation of timing of re-appearance of VBNC Legionella for risk assessment in hospital water distribution systems / Marinelli, L.; Cottarelli, A.; Solimini, A. G.; Del Cimmuto, A.; De Giusti, M.. - In: ANNALI DI IGIENE MEDICINA PREVENTIVA E DI COMUNITÀ. - ISSN 1120-9135. - 29:5(2017), pp. 431-439. [10.7416/ai.2017.2175]

Evaluation of timing of re-appearance of VBNC Legionella for risk assessment in hospital water distribution systems

Marinelli, L.;Cottarelli, A.;Solimini, A. G.;Del Cimmuto, A.;De Giusti, M.
2017

Abstract

Background. In this study we estimated the presence of Legionella species, viable but non-culturable (VBNC), in hospital water networks. We also evaluated the time and load of Legionella appearance in samples found negative using the standard culture method. Methods. A total of 42 samples was obtained from the tap water of five hospital buildings. The samples were tested for Legionella by the standard culture method and were monitored for up to 12 months for the appearance of VBNC Legionella. Results. All the 42 samples were negative at the time of collection. Seven of the 42 samples (17.0%) became positive for Legionella at different times of monitoring. The time to the appearance of VBNC Legionella was extremely variable, from 15 days to 9 months from sampling. The most frequent Legionella species observed were Legionella spp and L. anisa and only in one sample L. pneumophila srg.1. Conclusion. Our study confirms the presence of VBNC Legionella in samples resulting negative using the standard culture method and highlights the different time to its appearance that can occur several months after sampling. The results are important for risk assessment and risk management of engineered water systems.
2017
continuous chlorination treatment; health care related legionellosis; hospital water network; legionella appearance time; legionella species; legionellosis risk assessment; viable but non-culturable legionella; public health; environmental and occupational health; infectious diseases
01 Pubblicazione su rivista::01a Articolo in rivista
Evaluation of timing of re-appearance of VBNC Legionella for risk assessment in hospital water distribution systems / Marinelli, L.; Cottarelli, A.; Solimini, A. G.; Del Cimmuto, A.; De Giusti, M.. - In: ANNALI DI IGIENE MEDICINA PREVENTIVA E DI COMUNITÀ. - ISSN 1120-9135. - 29:5(2017), pp. 431-439. [10.7416/ai.2017.2175]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1065161
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