Extended water stagnation in buildings during the COVID-19 pandemic increases the risks posed by opportunistic pathogens

© 2023 The Authors. Published by Elsevier Ltd..

The regrowth and subsequent exposure of opportunistic pathogens (OPs) whilst reopening buildings that have been locked down due to the stay-at-home restrictions to limit the spread of COVID-19, is a public health concern. To better understand such microbiological risks due to lowered occupancy and water demand in buildings, first and post-flush water samples (n = 48) were sampled from 24 drinking water outlets from eight university buildings in two campuses (urban and rural), with various end-user occupancies. Both campuses were served with chlorinated water originating from a single drinking water distribution system in South-East Queensland, situated 14 km apart, where the rural campus had lower chlorine residuals. Culture-dependent and culture-independent methods (such as flow cytometry, qPCR and 16S rRNA gene amplicon sequencing) were used concurrently to comprehensively characterise the OPs of interest (Legionella spp., Pseudomonas aeruginosa, and nontuberculous mycobacteria (NTM)) and the premise plumbing microbiome. Results showed that buildings with extended levels of stagnation had higher and diverse levels of microbial growth, as observed in taxonomic structure and composition of the microbial communities. NTM were ubiquitous in all the outlets sampled, regardless of campus or end-user occupancy of the buildings. qPCR and culture demonstrated prevalent and higher concentrations of NTM in buildings (averaging 3.25 log10[estimated genomic copies/mL]) with extended stagnation in the urban campus. Furthermore, flushing the outlets for 30 minutes restored residual and total chlorine, and subsequently decreased the levels of Legionella by a reduction of 1 log. However, this approach was insufficient to restore total and residual chlorine levels for the outlets in the rural campus, where both Legionella and NTM levels detected by qPCR remained unchanged, regardless of building occupancy. Our findings highlight that regular monitoring of operational parameters such as residual chlorine levels, and the implementation of water risk management plans are important for non-healthcare public buildings, as the levels of OPs in these environments are typically not assessed.

Medienart:	E-Artikel

Erscheinungsjahr:	2023
Erschienen:	2023

Enthalten in:	Zur Gesamtaufnahme - volume:21
Enthalten in:	Water research X - 21(2023) vom: 01. Dez., Seite 100201

Sprache:	Englisch

Beteiligte Personen:	Huang, Casey K [VerfasserIn] Weerasekara, Anjani [VerfasserIn] Lu, Ji [VerfasserIn] Carter, Robyn [VerfasserIn] Weynberg, Karen D [VerfasserIn] Thomson, Rachel [VerfasserIn] Bell, Scott [VerfasserIn] Guo, Jianhua [VerfasserIn]

Links:	Volltext

Themen:	Building microbiome COVID-19 pandemic Journal Article Legionella Nontuberculous mycobacteria (NTM) Opportunistic pathogens Premise plumbing

Anmerkungen:	Date Revised 16.12.2023 published: Electronic-eCollection Citation Status PubMed-not-MEDLINE

doi:	10.1016/j.wroa.2023.100201

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PPN (Katalog-ID):	NLM365895792