Investigation of exposure to recreational waters as a risk for colonisation with carbapenemase and extended spectrum beta lactamase producing enterobacterales
Farrell, Maeve Louise
Farrell, Maeve Louise
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Publication Date
2024-01-08
Type
Thesis
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Abstract
Antimicrobial resistance (AMR) is one of the greatest human health risks globally. Traditionally, AMR has been considered as a clinical issue, but recently, non-clinical settings have come to light as a significant contributor to the spread of antimicrobial resistance genes (ARGs), epidemic strains and mobile genetic elements. There is an increasing need to better understand the complex role of the environment in the dissemination of AMR, with exposure to AMR in recreational waters representing potential public health risks. In particular, extended-spectrum beta-lactamase producing Enterobacterales (ESBL-PE) and carbapenemase-producing Enterobacterales (CPE) have been identified as a growing concern. Previous research both nationally and internationally has identified the presence of these bacteria in natural recreational waters. Furthermore, a UK study detailed that frequent surfers were significantly more likely to carry blaCTX-M producing Escherichia coli than non water users. The aim of this research wasto investigate whether exposure to natural recreational waters is associated with gut colonisation with AMR Enterobacterales in Ireland. Chapter Two details a scoping review which evaluated the potential for exposure to waterborne organisms of public health concern in European recreational waters. The scoping review encompassed 60 studies from 18 European countries. Waterborne organisms of public health concern(WOPHC)identified included viruses, whichwere detected in 52% of the analysed samples from the included studies, followed by bacteria (35%) and protozoa (12%). Of the assessed samplesinvestigating AMR (n= 442, 5.4%), AMR bacteria were detected in 47%(n=208), indicating their widespread occurrence in bathing waters. Chapter Three comprised of a point prevalence study of an investigation into the prevalence of colonisation with ESBL-PE and carbapenem resistant Enterobacterales (CRE) in recreational water users (WU) and age matched controls. This research was conducted between September 2020 and October 2021, and involved recruitment of 411 participants (199 water users, 212 controls) from Ireland. One faecal sample per participant was collected and analysed to investigate the association between recreational water exposure and colonisation by AMR Enterobacterales, specifically ESBL-PE and CPE. A secondary objective was to examine whether there was an increase in the prevalence of colonisation with ESBL-PE or CPE during the bathing season (1st June to 15th September). To investigate this, participants were invited to submit a second faecal sample, with 136 participants partaking. Overall,ESBL-PE was detected in 7.1% of participants (7 water users, 22 controls), while carbapenem resistant Enterobacterales (CRE) was detected in 2.2% (4 water users, 5 controls). Significantly lower rates of ESBL-PE colonisation were observed among water users compared to controls (risk ratio = 0.34, 95% CI 0.148 to 0.776, χ2 7.37, p = 0.007). Five participants carried ESBL-PE in both sampling periods (1 WU, 4 Controls). There were six new detections of ESBL-PE in the bathing season (4 WU, 2 Controls). In Chapter Four, a 12-month longitudinal study was conducted on 45 participants to assess the persistence of AMR organisms in the human gut. Six faecal samples per participant were collected and analysed for CPE and ESBL-PE over one year and the relationship between persistent colonisation and exposure to natural waters was investigated. ESBL-E. coli (ESBL-EC) was detected in at least one sample from 11 participants (24.4%). The median duration of colonisation with ESBL-PE was identified as 10.3 months (4-23 month range). A lower incidence of colonisation in WU was also observed in this longitudinal study. In conclusion, this thesis provides evidence regarding the occurrence and persistence of ESBL-PE carriage in healthy individuals inIreland. Recreational exposure to bathing water in Ireland was associated with a lower prevalence of colonisation by ESBL-PE and CRE. This study contributes significantly to the existing evidence on the relationship between human interactions with natural environments and their health impacts. Further investigation is required to elucidate the potential for a dose response relationship between colonisation and poor water quality. Findings of this work emphasise the importance of maintaining surveillance and implementing effective control measures to prevent further dissemination of AMR in the community. Furthermore, multiple human infection associated sequence types and mobile genetic elements were identified among isolates originating from healthy participantsindicating a high potential for transmission of AMR genes. This research highlights the potential of faecal colonisation monitoring as a method of surveillance of emerging AMR organism threats in the community, and could contribute to the implementation of suitable management and monitoring strategies.
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NUI Galway