The antimicrobial resistance profiles of Escherichia coli and Pseudomonas aeruginosa isolated from private groundwater wells in the Republic of Ireland. (15th January 2023)

• Record Type: Journal Article
• Authors: Andrade, Luisa; Chique, Carlos; Hynds, Paul; Weatherill, John; O'Dwyer, Jean
• Is Part Of: Environmental pollution. Volume 317(2023)
• Publication Date: 2023-01-15
• Subjects: Antimicrobial resistance -- Groundwater -- Private wells -- Escherichia coli -- Pseudomonas aeruginosa; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.120817
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The role of the natural environment in the dissemination of antimicrobial resistant bacteria has been increasingly recognised in the literature. However, knowledge surrounding the critical factors and mechanisms mediating their occurrence is still limited, particularly in relatively 'pristine' groundwater environments. In the Republic of Ireland (RoI), a country characterised by high groundwater reliance, household-based (unregulated) wells provide drinking water to 11% of the population. These private wells are generally located in rural areas, where the risk of microbiological contamination is high due to intensive agricultural practices and high reliance on domestic wastewater treatment systems; both of which are also potential sources of antimicrobials and antimicrobial resistant bacteria. Accordingly, the current research sought to elucidate current rates of antimicrobial resistant bacteria and the principal factors associated with their presence in private wells in the RoI. A total of 250 samples (from 132 wells nationwide) were assessed for the presence of faecal ( Escherichia coli) and environmental ( Pseudomonas aeruginosa ) bacteria, with single isolates from each contaminated sample tested phenotypically against 18 and 9 antimicrobials, respectively. Findings show that while 16.7% of E. coli (n = 8/48) were categorically resistant to ≥1 antimicrobial, with a further 79.2% classified as intermediately resistant, no categorical resistance was found among P. aeruginosa isolates (n = 0/6), with just one intermediately resistant isolate detected. Multivariate regression modelling indicates significantly higher odds of resistant E. coli detection in concurrence with elevated cattle density (OR = 1.028, p = 0.032), aligning with findings of highest resistance rates to veterinary antimicrobials (e.g., streptomycin = 14.6%, tetracycline = 12.5%, and ampicillin = 12.5%). Multivariate model results also suggest overland flow culminating in direct wellhead ingress as a primary ingress mechanism for resistant E. coli . Study findings may inform groundwater source protection initiatives and antimicrobial resistance surveillance moving forward. Graphical abstract: Image 1 Highlights: 132 private groundwater wells in rural Ireland sampled/assessed in 2019 and 2021. E. coli and P. aeruginosa detected in 21.6% and 4.8% of samples, respectively. Antimicrobial resistance present in 16.7% of E. coli and none of the P. aeruginosa Resistant E. coli associated with veterinary antimicrobials and cattle density. Direct ingress viewed as principal contamination mechanism for resistant E. coli