Papers by Jean O'Dwyer
Antibiotic-resistant (pathogenic and non-pathogenic) organisms and genes are now acknowledged as ... more Antibiotic-resistant (pathogenic and non-pathogenic) organisms and genes are now acknowledged as significant emerging aquatic contaminants with potentially adverse human and ecological health impacts, and thus require monitoring. This study is the first to investigate levels of resistance among Irish groundwater (private wells) samples; Escherichia coli isolates were examined against a panel of commonly prescribed human and veterinary therapeutic antibiotics, followed by determination of the causative factors of resistance. Overall, 42 confirmed E. coli isolates were recovered from a groundwater-sampling cohort. Resistance to the human panel of antibiotics was moderate; nine (21.4%) E. coli isolates demonstrated resistance to one or more human antibiotics. Conversely, extremely high levels of resistance to veterinary antibiotics were found, with all isolates presenting resistance to one or more veterinary antibiotics. Particularly high levels of resistance (93%) were found with respect to the aminoglycoside class of antibiotics. Results of statistical analysis indicate a significant association between the presence of human (multiple) antibiotic resistance (p = 0.002–0.011) and both septic tank density and the presence of vulnerable sub-populations (<5 years). For the veterinary antibiotics, results point to a significant relationship (p = <0.001) between livestock (cattle) density and the prevalence of multiple antibiotic resistant E. coli. Groundwater continues to be an important resource in Ireland, particularly in rural areas; thus, results of this preliminary study offer a valuable insight into the prevalence of antibiotic resistance in the hydrogeological environment and establish a need for further research with a larger geological diversity.
Evaluation of levels of antibiotic resistance in groundwater-derived E. coli isolates in the Midwest of Ireland and elucidation of potential predictors of resistance.
A geo-statistical investigation of agricultural and infrastructural risk factors associated with primary verotoxigenic E. coli (VTEC) infection in the Republic of Ireland, 2008–2013
Ireland reports the highest incidence of verotoxigenic Escherichia coli (VTEC) infection in Europ... more Ireland reports the highest incidence of verotoxigenic Escherichia coli (VTEC) infection in Europe. This study investigated potential risk factors for confirmed sporadic and outbreak primary VTEC infections during 2008-2013. Overall, 989 VTEC infections including 521 serogroup O157 and 233 serogroup O26 were geo-referenced to 931 of 18488 census enumeration areas. The geographical distribution of human population, livestock, unregulated groundwater sources, domestic wastewater treatment systems (DWWTS) and a deprivation index were examined relative to notification of VTEC events in 524 of 6242 rural areas. Multivariate modelling identified three spatially derived variables associated with VTEC notification: private well usage (odds ratio (OR) 6.896, p <0.001), cattle density (OR 1.002, p <0.001) and DWWTS density (OR 0.978, p = 0.002). Private well usage (OR 18.727, p <0.001) and cattle density (OR 1.001, p = 0.007) were both associated with VTEC O157 infection, while DWWTS density (OR 0.987, p = 0.028) was significant within the VTEC O26 model. Findings indicate that VTEC infection in the Republic of Ireland is particularly associated with rural areas, which are associated with a ubiquity of pathogen sources (cattle) and pathways (unregulated groundwater supplies).
Cultivated organic soils, which are a large source of CO2 emissions, are of particular interest i... more Cultivated organic soils, which are a large source of CO2 emissions, are of particular interest in the Republic
of Ireland where peatlands cover 20 % of the landscape. For accurate accounting and national reporting of
greenhouse gas (GHG) emissions, there is a need to calculate the total land area used for cultivation activity
on drained organic soils. Peatlands (organic soils) in Ireland are also used for arable farming, which results in
particularly high greenhouse gas emissions per unit area. However, the Irish National Inventory Report to the
United Nations Framework Convention on Climate Change lacks mention of this type of land use. The actual
area of organic soils under arable land use (cropland) in Ireland has, thus far, not been quantified. Here we
provide a first estimate of the area of organic soil that is used for arable farming in Ireland. Through map
overlay analysis using GIS in combination with probability sampling and ground truthing, we estimate the area
of organic soils under arable cropping at 1,235 ha, which is considerably lower than the estimate of 3,688 ha
based on map overlays alone. This research provides information to support improved accounting of organic
soils under cultivation and may contribute to reducing uncertainty in national reporting of GHG emissions,
thus providing a more reliable basis for strategies aimed at reducing GHG emissions in Ireland in the future.
This study assesses the microbiological quality of 132 Private Water Supplies (PWS's) serving... more This study assesses the microbiological quality of 132 Private Water Supplies (PWS's) serving individual houses in the Midwestern region of Ireland. Three factors: Aquifer Type (Bedrock or Sand/Gravel), Soil Characteristics (Great Soil Group, Soil Depth and Soil Drainage) and Rainfall (mm), were chosen as independent variables that can affect the vulnerability of a groundwater body. Using a Geographic Information System (GIS) the relative hydrogeological and climatological features unique to each sampling location was derived. Utilising this information, Statistical Correlations were derived using Pearson's correlation coefficient. Where significant correlations were deuced, a Logistic Regression (LR) model was then used to predict the probability of contamination of private water supplies with Escherichia coli.
The need for new antibiotics is greater than ever due to the emergence of multidrug resistant pat... more The need for new antibiotics is greater than ever due to the emergence of multidrug resistant pathogens. The value and importance of antibiotics cannot be overestimated, and they must not be considered as commodities. Antibiotic have revolutionised the field of medicine and we are reliant on them to treat infectious diseases. Since the introduction of penicillin in 1943, there has been a mismanagement of antibiotics. This has allowed bacterial antibiotic resistance to emerge. This has been illustrated by many of the pathogens associated with epidemics of human disease evolving multidrug-resistant (MDR) forms following subsequent use of antibiotics. The situation with regards to antibiotic resistance is grim. There is a substantial financial and clinical burden being placed on health care systems by the pandemic of resistance mechanisms. Fortunately, many bacterial pathogens respond to empirical treatment with antibiotic agents administered in the community. Despite the negative outl...
Background: Private groundwater sources in the Republic of Ireland currently provide a daily drin... more Background: Private groundwater sources in the Republic of Ireland currently provide a daily drinking water supply to an estimated 720,000 people or 17% of the national population. Consumers of untreated groundwater are at an increased risk of infection and disease from pathogenic microorganisms, with Blackburn et al. (2004) noting that diseases caused by waterborne pathogens continue to be a leading cause of illness in the United States. Based on data relating to verotoxigenic E. coli (VTEC) outbreaks in Ireland, Garvey et al. (2010) suggest that drinking water in households using private wells was a significant factor in an overall outbreak increase. More recently, a surge in VTEC notifications between September and November 2011 has been reported in Ireland, with private well usage again highlighted as a significant source (McKeown & Garvey, 2011). A recent study predicts a mean crude incidence rate among private well users in Ireland of 28.3/100,000, which is 20-30 times higher ...
Background: Private groundwater sources in the Republic of Ireland currently provide a daily drin... more Background: Private groundwater sources in the Republic of Ireland currently provide a daily drinking water supply to an estimated 720,000 people or 17% of the national population. Consumers of untreated groundwater are at an increased risk of infection and disease from pathogenic microorganisms, with Blackburn et al. (2004) noting that diseases caused by waterborne pathogens continue to be a leading cause of illness in the United States. Based on data relating to verotoxigenic E. coli (VTEC) outbreaks in Ireland, Garvey et al. (2010) suggest that drinking water in households using private wells was a significant factor in an overall outbreak increase. More recently, a surge in VTEC notifications between September and November 2011 has been reported in Ireland, with private well usage again highlighted as a significant source (McKeown & Garvey, 2011). A recent study predicts a mean crude incidence rate among private well users in Ireland of 28.3/100,000, which is 20-30 times higher ...
This study assesses the microbiological quality of 132 Private Water Supplies (PWS's) serving... more This study assesses the microbiological quality of 132 Private Water Supplies (PWS's) serving individual houses in the Midwestern region of Ireland. Three factors: Aquifer Type (Bedrock or Sand/Gravel), Soil Characteristics (Great Soil Group, Soil Depth and Soil Drainage) and Rainfall (mm), were chosen as independent variables that can affect the vulnerability of a groundwater body. Using a Geographic Information System (GIS) the relative hydrogeological and climatological features unique to each sampling location was derived. Utilising this information, Statistical Correlations were derived using Pearson's correlation coefficient. Where significant correlations were deuced, a Logistic Regression (LR) model was then used to predict the probability of contamination of private water supplies with Escherichia coli.
The impact of meteorology on the occurrence of waterborne outbreaks of vero cytotoxin-producing Escherichia coli (VTEC): A logistic regression approach
This study analyses the relationship between meteorological phenomena and outbreaks of waterborne... more This study analyses the relationship between meteorological phenomena and outbreaks of waterborne transmitted verocytotoxin producing Escherichia coli (VTEC) in the Republic of Ireland over an 8-year period (2005–2012). Data pertaining to the notification of waterborne VTEC outbreaks were extracted from the Computerised Infectious Disease Reporting system which is administered through the national Health Protection Surveillance Centre as part of the Health Service Executive. Rainfall and temperature data were obtained from the national meteorological office and categorised as cumulative rainfall, heavy rainfall events in the previous 7 days and mean temperature. Regression analysis was performed using logistic regression (LR) analysis. The LR model was significant (p < 0.001), with all independent variables: cumulative rainfall, heavy rainfall and mean temperature making a statistically significant contribution to the model. The study has found that rainfall, particularly heavy rainfall in the preceding 7 days of an outbreak is a strong statistical indicator of a waterborne outbreak and that temperature also impacts waterborne VTEC outbreak occurrence.
The travelling population is increasing globally year on year. International tourist arrival figu... more The travelling population is increasing globally year on year. International tourist arrival figures reached 1087 million in 2013 and 1133 million in 2014; of which 53% and 54% respectively accounted for air transport. The water on board aircraft is sourced from surface or ground water; piped to a central filling point and distributed to each aircraft by water service vehicles at the home base or at the destination airport. The purpose of this study was to ascertain the microbial, chemical (pH; Total and Free chlorine) and physical (temperature) quality of water from two aircraft, long- and short-haul, as well as from the original water source and the water service vehicle. A total of 154 water samples were collected and analysed. Long-haul flights were found to be significantly poorer in terms of microbial quality than short haul flights (p = 0.015). Furthermore, correlation and regression analysis showed that the water service vehicle was a significant source of increased microbial load in aircraft. Microbial diversity was also demonstrated, with 37 bacterial species identified belonging to eight classes: γ-Proteobacteria; β-Proteobacteria; α-Proteobacteria; Bacilli; Actinobacteria; Flavobacteria; Sphingobacteria and Cytophaga; using phenotypic and 16S rDNA sequence-based analysis. We present a novel quantified study of aircraft-related potable water supplies.
Anthropogenic climate change is currently one of the biggest threats to mankind; with increases i... more Anthropogenic climate change is currently one of the biggest threats to mankind; with increases in average global temperature predicted to effect natural systems with detrimental consequences to human health. This chapter focuses on climate change and waterborne infectious disease. Meteorological phenomena can play a leading role in waterborne infectious disease epidemiology. The impact of meteorology on waterborne disease is moderated through the effects of rainfall frequency and intensity as well as temperature; both air and water temperatures; both of which are discussed within this section. Also investigated are emerging waterborne infectious diseases which may prove to be problematic in coming years and present problems to countries unequipped to monitor, report and moderate diverse waterborne pathogens. This chapter provides a focus on Europe and offers recommendations for adaptability, prevention and preparation which can be implemented at a global level.
The need for new antibiotics is greater than ever due to the emergence of multidrug resistant pat... more The need for new antibiotics is greater than ever due to the emergence of multidrug resistant pathogens. The value and
importance of antibiotics cannot be overestimated, and they must not be considered as commodities. Antibiotic have
revolutionised the field of medicine and we are reliant on them to treat infectious diseases. Since the introduction of
penicillin in 1943, there has been a mismanagement of antibiotics. This has allowed bacterial antibiotic resistance to
emerge. This has been illustrated by many of the pathogens associated with epidemics of human disease evolving
multidrug-resistant (MDR) forms following subsequent use of antibiotics. The situation with regards to antibiotic
resistance is grim. There is a substantial financial and clinical burden being placed on health care systems by the pandemic
of resistance mechanisms. Fortunately, many bacterial pathogens respond to empirical treatment with antibiotic agents
administered in the community. Despite the negative outlook by big pharma companies, it is vital that there should be no
let-up in the search for new novel antimicrobial compounds that target novel resistance mechanisms that could potentially
be resistant proof. By academia and industry working together novel therapies could be examined in more detail and could
potentially slow down the rate at which antibiotic resistance is presently emerging. It is imperative that a concerted
offensive approach is taken and that full advantage of new understandings and technology is fully utilised.
Lime in the limelight
Journal of Cleaner Production, 2014
Lime is one of the most versatile chemicals in the world. There are two main types of lime produc... more Lime is one of the most versatile chemicals in the world. There are two main types of lime produced, quicklime and hydrated lime. Quicklime is formed during the calcination of limestone. Hydrated lime results from subsequent hydration of quicklime where required. Lime has been innovatively rediscovered to be a more environmentally sustainable product aiding in the implementation of new cleaner systems from, remediation of acid mine draining to key uses in water source treatment. Further research has been undertaken to investigate new roles for lime as an antimicrobial compound and environmentally friendly biocide. The uses of lime have evolved steadily over time; this is thought to be due to its ease of acquisition, affordable price and unique versatile properties. The aim of this literature review is to provide an informed view on the current application of lime and its potential novel uses in the future.
Journal of Water and Health, Jan 2014
Determining the likelihood that groundwater contains faecal coliforms can aid water resource mana... more Determining the likelihood that groundwater contains faecal coliforms can aid water resource management in facilitating the protection of drinking water supplies. This study assesses the incidence of the faecal indicator organism Escherichia coli in 125 private water supplies (PWSs) serving individual houses in the Mid-West Region of Ireland. Two factors, aquifer type and rainfall (mm), were chosen as independent variables that can affect the vulnerability of a groundwater body. Using a geographical information system, the relative hydrogeological and climatological features unique to each sampling location were derived. Utilising this information, a logistic regression (LR) model was used to predict the probability of contamination of PWSs with E. coli. The model contained two independent variables: rainfall (mm; p < 0.001) and aquifer characteristics (p = 0.001). The full model, containing both predictors, was statistically significant at p < 0.001, indicating that the model distinguished between the independent variables' relationship to the incidence of contamination. The likelihood of E. coli contamination is greater with increased rainfall and in areas where a bedrock aquifer is dominant. The LR model explained between 27.4% (Cox and Snell R squared) and 36.8% (Nagelkerke R squared) of the variance in contamination and correctly classified 75.2% of cases.
Conference Presentations by Jean O'Dwyer
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Papers by Jean O'Dwyer
Evaluation of levels of antibiotic resistance in groundwater-derived E. coli isolates in the Midwest of Ireland and elucidation of potential predictors of resistance.
of Ireland where peatlands cover 20 % of the landscape. For accurate accounting and national reporting of
greenhouse gas (GHG) emissions, there is a need to calculate the total land area used for cultivation activity
on drained organic soils. Peatlands (organic soils) in Ireland are also used for arable farming, which results in
particularly high greenhouse gas emissions per unit area. However, the Irish National Inventory Report to the
United Nations Framework Convention on Climate Change lacks mention of this type of land use. The actual
area of organic soils under arable land use (cropland) in Ireland has, thus far, not been quantified. Here we
provide a first estimate of the area of organic soil that is used for arable farming in Ireland. Through map
overlay analysis using GIS in combination with probability sampling and ground truthing, we estimate the area
of organic soils under arable cropping at 1,235 ha, which is considerably lower than the estimate of 3,688 ha
based on map overlays alone. This research provides information to support improved accounting of organic
soils under cultivation and may contribute to reducing uncertainty in national reporting of GHG emissions,
thus providing a more reliable basis for strategies aimed at reducing GHG emissions in Ireland in the future.
importance of antibiotics cannot be overestimated, and they must not be considered as commodities. Antibiotic have
revolutionised the field of medicine and we are reliant on them to treat infectious diseases. Since the introduction of
penicillin in 1943, there has been a mismanagement of antibiotics. This has allowed bacterial antibiotic resistance to
emerge. This has been illustrated by many of the pathogens associated with epidemics of human disease evolving
multidrug-resistant (MDR) forms following subsequent use of antibiotics. The situation with regards to antibiotic
resistance is grim. There is a substantial financial and clinical burden being placed on health care systems by the pandemic
of resistance mechanisms. Fortunately, many bacterial pathogens respond to empirical treatment with antibiotic agents
administered in the community. Despite the negative outlook by big pharma companies, it is vital that there should be no
let-up in the search for new novel antimicrobial compounds that target novel resistance mechanisms that could potentially
be resistant proof. By academia and industry working together novel therapies could be examined in more detail and could
potentially slow down the rate at which antibiotic resistance is presently emerging. It is imperative that a concerted
offensive approach is taken and that full advantage of new understandings and technology is fully utilised.
Conference Presentations by Jean O'Dwyer