Spatiotemporal modelling of antimicrobial resistance in the Irish subsurface environment

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dc.check.date2026-09-30
dc.contributor.advisorO'Dwyer, Jean
dc.contributor.advisorWeatherill, John
dc.contributor.advisorexternalHynds, Paulen
dc.contributor.authorAlbuquerque de Andrade, Luisaen
dc.contributor.funderScience Foundation Ireland
dc.contributor.funderGeological Survey of Ireland
dc.date.accessioned2023-06-13T11:22:34Z
dc.date.available2023-06-13T11:22:34Z
dc.date.issued2023-01-31en
dc.date.submitted2023-01-31
dc.description.abstractAntimicrobial resistance represents a significant public health risk, with global estimates indicating that as many as 1.27 million deaths were directly attributable to antimicrobial resistant infections in 2019. The adverse human health effects attributed to the continuous rapid spread of antimicrobial resistance are particularly pressing in the aftermath of the COVID-19 pandemic, which highlighted societies’ acute susceptibility to infectious diseases in the absence of effective treatment options. The proliferation of antimicrobial resistant bacteria (ARB) was also acknowledged as the key emerging issue of environmental concern by the United Nations Environmental Programme in 2017. Despite this, the natural environment’s role in the spread of ARB-related infections remains unclear. In this context, ARB presence in groundwater resources represents a noteworthy concern, as these can act as prospective reservoirs, while offering a direct exposure route to the over 2.2 billion groundwater consumers worldwide. In the Republic of Ireland (RoI), private groundwater wells supply approximately 11% of the population, with these users already associated with increased incidence rates of waterborne infections. Indeed, Irish private wells have been linked to persistent microbiological contamination attributable to inadequate on-site domestic wastewater treatment systems and the widespread agricultural activities associated with the Irish rural landscape; both of which are also potential sources of ARB. Thus, and in combination with a diverse (hydro)geological profile and a temperate climate characterised by the absence of a dry season, the RoI may present the ‘perfect storm’ for groundwater contamination by ARB and subsequent adverse human health effects. To-date, however, just one spatiotemporally limited study exists which investigates this issue within the RoI, leading to significant knowledge gaps regarding the spatial and temporal dynamics of ARB contamination in Irish groundwater environments. Accordingly, the current research blends systematic literature review and pooled analyses, traditional hydrogeological fieldwork, geo-referencing, molecular microbiology, analytical chemistry, genome sequencing, and statistical modelling to quantify occurrence rates and elucidate the potential drivers of ARB contamination in groundwater resources. The overarching aim of this research is to better understand ARB presence in Irish groundwater supplies and inform appropriate source-protection strategies, in line with Sustainable Development Goals 3 ("good health and well-being") and 6 ("clean water and sanitation for all”). Research findings indicate that groundwater resources may represent a global reservoir/pathway for ARB, with 80.2% ± 29.0 of groundwater-derived bacteria from studies in the systematic review exhibiting resistance/intermediate resistance to at least one antimicrobial. In the RoI specifically, the analyses of monitoring data from a 10-year period showed Escherichia coli contamination in 66.7% of monitored (regulated) water supplies nationwide at least once, with pastoral agriculture (a well-known potential source of ARB in addition to faecal bacteria contamination) identified as a key risk factor. Additionally, fieldwork data identified antimicrobial resistance in 16.7% of Escherichia coli (8/48) but none of the Pseudomonas aeruginosa (0/6) collected from 132 geographically dispersed (unregulated) private wells in the RoI sampled during autumn 2019 and summer 2021. Fieldwork results also revealed that the presence of resistant E. coli was significantly associated with increased local cattle density (OR = 1.028; p = 0.037), having likely been transported into wells via surface run-off followed by direct wellhead ingress. Moreover, lack of statistical significance (p ≥ 0.084) between overarchingly low concentrations of co-selective (i.e., metal/metalloid) parameters and antimicrobial resistance gene abundance in E. coli isolates lead to the hypothesis that E. coli may have acquired resistance prior to entering these groundwater supply environments. With that, findings suggest contamination of rural groundwater resources with ARB in the RoI as being highly preventable by ensuring appropriate source protection measures. Research results bridge the gap between hydrology, geoscience, and heath, promote capacity building, and inform the development of effective policy for groundwater management and antimicrobial resistance action plans into the future.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationAlbuquerque de Andrade, L. 2023. Spatiotemporal modelling of antimicrobial resistance in the Irish subsurface environment. PhD Thesis, University College Cork.
dc.identifier.endpage245
dc.identifier.urihttps://hdl.handle.net/10468/14566
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2023, Luisa Albuquerque de Andradeen
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectGroundwater
dc.subjectDrinking water
dc.subjectEscherichia coli
dc.subjectPrivate wells
dc.subjectAntimicrobial resistant bacteria
dc.subjectPseudomonas aeruginosa
dc.subjectAntimicrobial resistance genes
dc.subjectMetal resistance genes
dc.subjectTrace metals
dc.titleSpatiotemporal modelling of antimicrobial resistance in the Irish subsurface environment
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD - Doctor of Philosophyen
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