ABSTRACT
Recreational bathing waters are complex systems with diverse inputs from multiple anthropogenic and zoogenic sources of faecal contamination. Faecal contamination is a substantial threat to water quality and public health. Here we present a comprehensive strategy to estimate the contribution of faecal indicator bacteria (FIB) from different biological sources on two at-risk beaches in Dublin, Ireland. The daily FIB loading rate was determined for three sources of contamination: a sewage-impacted urban stream, dog and wild bird fouling. This comparative analysis determined that the stream contributed the highest daily levels of FIB, followed by dog fouling. Dog fouling may be a significant source of FIB, contributing approximately 20 % of E. coli under certain conditions, whereas wild bird fouling contributed a negligible proportion of FIB (<3 %). This study demonstrates that source-specific quantitative microbial source apportionment (QMSA) strategies are vital to identify primary public health risks and target interventions to mitigate faecal contamination.
Subject(s)
Environmental Monitoring , Feces , Feces/microbiology , Environmental Monitoring/methods , Animals , Ireland , Bathing Beaches , Water Microbiology , Water Pollution/statistics & numerical data , Water Pollution/analysis , Dogs , Sewage/microbiology , Escherichia coli/isolation & purification , Water Quality , Bacteria/isolation & purification , Birds/microbiologyABSTRACT
Wastewater-based epidemiology (WBE) has been an important tool for population surveillance during the COVID-19 pandemic and continues to play a key role in monitoring SARS-CoV-2 infection levels following reductions in national clinical testing schemes. Studies measuring decay profiles of SARS-CoV-2 in wastewater have underscored the value of WBE, however investigations have been hampered by high biosafety requirements for SARS-CoV-2 infection studies. Therefore, surrogate viruses with lower biosafety standards have been used for SARS-CoV-2 decay studies, such as murine hepatitis virus (MHV), but few studies have directly compared decay rates of both viruses. We compared the persistence of SARS-CoV-2 and MHV in wastewater, using 50 % tissue culture infectious dose (TCID50) and reverse transcription quantitative polymerase chain reaction (RT-qPCR) assays to assess infectious virus titre and viral gene markers, respectively. Infectious SARS-CoV-2 and MHV indicate similar endpoints, however observed early decay characteristics differed, with infectious SARS-CoV-2 decaying more rapidly than MHV. We find that MHV is an appropriate infectious virus surrogate for viable SARS-CoV-2, however inconsistencies exist in viral RNA decay parameters, indicating MHV may not be a suitable nucleic acid surrogate across certain temperature regimes. This study highlights the importance of sample preparation and the potential for decay rate overestimation in wastewater surveillance for SARS-CoV-2 and other pathogens.
Subject(s)
Murine hepatitis virus , RNA, Viral , SARS-CoV-2 , Wastewater , Wastewater/virology , SARS-CoV-2/genetics , Murine hepatitis virus/physiology , COVID-19 , Animals , RNA StabilityABSTRACT
Objectives: Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events (irAEs), of which endocrinopathies are common. We characterized endocrine and non-endocrine irAEs in cancer patients receiving ICIs, identified risk factors for their development and established whether endocrine and non-endocrine irAEs were differentially associated with improved cancer prognosis. Design and methods: Single-center, retrospective cohort study of patients with advanced or metastatic solid tumors receiving at least one ICI treatment cycle (242 men, 151 women, median age 65 years). Main outcome measures were incidence of any irAE during the study period, overall survival and time to treatment failure. Results: Non-endocrine irAEs occurred in 32% and endocrine irAEs in 12% of patients. Primary thyroid dysfunction was the most common endocrine irAE (9.5%) and the majority of endocrinopathies required permanent hormone replacement. Women had an increased risk of developing endocrine irAEs (p = 0.017). The biggest survival advantage occurred in patients who developed both endocrine and non-endocrine irAEs (overall survival: HR 0.16, CI 0.09-0.28). Time to treatment failure was also significantly improved in patients who developed endocrine irAEs (HR 0.49, CI 0.34 - 0.71) or both (HR 0.41, CI 0.25 - 0.64) but not in those who only developed non-endocrine irAEs. Conclusions: Women may have increased risk of endocrine irAEs secondary to ICI treatment. This is the first study to compare the effects of endocrine irAEs with non-endocrine irAEs on survival. Development of endocrine irAEs may confer survival benefit in ICI treatment and future, prospective studies are needed to elucidate this.
Subject(s)
Endocrine System Diseases , Immune Checkpoint Inhibitors , Neoplasms , Humans , Immune Checkpoint Inhibitors/adverse effects , Immune Checkpoint Inhibitors/therapeutic use , Female , Male , Retrospective Studies , Aged , Endocrine System Diseases/chemically induced , Endocrine System Diseases/epidemiology , Neoplasms/drug therapy , Neoplasms/mortality , Middle Aged , Prognosis , Aged, 80 and over , Adult , Survival Rate , Risk FactorsABSTRACT
The objective of this study was to comprehensively characterise the resistome, the collective set of antimicrobial resistance genes in a given environment, of two rivers, from their source to discharge into the sea, as these flow through areas of different land use. Our findings reveal significant differences in the riverine resistome composition in areas of different land uses, with increased abundance and diversity of AMR in downstream agricultural and urban locations, with the resistome in urban areas more similar to the resistome in wastewater. The changes in resistome were accompanied by changes in microbial communities, with a reduction in microbial diversity in downstream agricultural and urban affected areas, driven mostly by increased relative abundance in the phyla, Bacteroidetes and Proteobacteria. These results provide insight into how pollution associated with agricultural and urban activities affects microbial communities and influences AMR in aquatic water bodies. These results add valuable insights to form effective strategies for mitigating and preserving aquatic ecosystems. Overall, our study highlights the critical role of the environment in the development and dissemination of AMR and underscores the importance of adopting a One Health approach to address this global public health threat.
Subject(s)
Agriculture , Rivers , Rivers/microbiology , Agriculture/methods , Environmental Monitoring , Microbiota/drug effects , Water Microbiology , Drug Resistance, Bacterial/genetics , Wastewater/microbiology , Bacteria/genetics , Bacteria/drug effectsABSTRACT
Granulomatosis with polyangiitis (GPA) rarely involves the pituitary gland. Pituitary involvement has been reported in ~ 1% of all cases of GPA. Most commonly, pituitary swelling and inflammation results in symptoms due to pituitary mass effect and arginine vasopressin deficiency. To date, there are no pituitary-specific treatment guidelines for this rare condition. We present three patients with GPA-related hypophysitis highlighting the spectrum of pituitary involvement. All three patients were successfully treated with immunosuppressive regimens that included rituximab (RTX). Following remission induction with high-dose glucocorticoids, patients received 6 monthly RTX for remission maintenance. RTX was well tolerated without significant side effects.
Subject(s)
Granulomatosis with Polyangiitis , Hypophysitis , Pituitary Diseases , Humans , Granulomatosis with Polyangiitis/drug therapy , Treatment Outcome , Rituximab/therapeutic use , Pituitary Diseases/drug therapy , Hypophysitis/drug therapy , Pituitary Gland , Remission Induction , Retrospective StudiesABSTRACT
Bacteriophages have been shown to play an important role in harbouring and propagating antibiotic resistance genes (ARGs). Faecal matter contains high levels of phages, suggesting that faecal contamination of water bodies may lead to increased antimicrobial resistance (AMR) levels due to increased phage loading in aquatic environments. In this study, we assessed whether faecal pollution of three rivers (Rivers Liffey, Tolka, and Dodder) was responsible for increased levels of ARGs in phage particles using established phage-faecal markers, focusing on four ARGs (blaTEM, tet(O), qnrS, and sul1). We observed all four ARGs in phage fractions in all three rivers, with ARGs more frequently observed in agricultural and urban sampling sites compared to their source. These findings highlight the role of faecal pollution in environmental AMR and the impact of agricultural and urban activities on water quality. Furthermore, our results suggest the importance of including phages as indicators when assessing environmental AMR, as they serve as significant reservoirs of resistance genes in aquatic environments. This study provides important insights into the role of faecal pollution and phages in the prevalence of AMR in the environment and the need for their inclusion in future studies to provide a comprehensive understanding of environmental AMR.
Subject(s)
Bacteriophages , Bacteriophages/genetics , Genes, Bacterial , Drug Resistance, Microbial/genetics , Feces , Anti-Bacterial Agents/pharmacologyABSTRACT
OBJECTIVE: The optimal approach to the surveillance of non-functioning pituitary microadenomas (micro-NFPAs) is not clearly established. Our aim was to generate evidence on the natural history of micro-NFPAs to support patient care. DESIGN: Multi-centre, retrospective, cohort study involving 23 endocrine departments (UK NFPA consortium). METHODS: Clinical, imaging, and hormonal data of micro-NFPA cases between January, 1, 2008 and December, 21, 2021 were analysed. RESULTS: Data for 459 patients were retrieved [median age at detection 44 years (IQR 31-57)-152 males/307 females]. Four hundred and nineteen patients had more than two magnetic resonance imagings (MRIs) [median imaging monitoring 3.5 years (IQR 1.71-6.1)]. One case developed apoplexy. Cumulative probability of micro-NFPA growth was 7.8% (95% CI, 4.9%-8.1%) and 14.5% (95% CI, 10.2%-18.8%) at 3 and 5 years, respectively, and of reduction 14.1% (95% CI, 10.4%-17.8%) and 21.3% (95% CI, 16.4%-26.2%) at 3 and 5 years, respectively. Median tumour enlargement was 2â mm (IQR 1-3) and 49% of micro-NFPAs that grew became macroadenomas (nearly all >5â mm at detection). Eight (1.9%) patients received surgery (only one had visual compromise with surgery required >3 years after micro-NFPA detection). Sex, age, and size at baseline were not predictors of enlargement/reduction. At the time of detection, 7.2%, 1.7%, and 1.5% patients had secondary hypogonadism, hypothyroidism, and hypoadrenalism, respectively. Two (0.6%) developed hypopituitarism during follow-up (after progression to macroadenoma). CONCLUSIONS: Probability of micro-NFPA growth is low, and the development of new hypopituitarism is rare. Delaying the first follow-up MRI to 3 years and avoiding hormonal re-evaluation in the absence of tumour growth or clinical manifestations is a safe approach for micro-NFPA surveillance.
Subject(s)
Adenoma , Hypopituitarism , Pituitary Neoplasms , Male , Female , Humans , Adult , Middle Aged , Pituitary Neoplasms/diagnostic imaging , Pituitary Neoplasms/epidemiology , Pituitary Neoplasms/complications , Retrospective Studies , Cohort Studies , Adenoma/diagnostic imaging , Adenoma/epidemiology , Hypopituitarism/complications , United Kingdom/epidemiologyABSTRACT
The EU Bathing Water Directive (BWD) requires member states to assess bathing water quality according to the levels of faecal indicator bacteria (FIB) in designated bathing areas. However, this criterion has two significant limitations given that the BWD does not; (i) account for differences in hydrodynamic properties of bathing waters and, (ii) assumes that all faecal pathogens decay equally in aquatic environments. This study simulated sewage discharge events in three hypothetical aquatic environments characterised by different advection and dispersion parameters in the solute transport equation. Temporal changes in the downstream concentration of six faecal indicators were determined in simulations that utilised measured decay rates of each faecal indicator from a programme of controlled microcosm experiments in fresh and seawater environments. The results showed that the decay rates of faecal indicators are not a critical parameter in advection dominant water bodies, such as in fast-flowing rivers. Therefore, faecal indicator selection is less important in such systems and for these, FIB remains the most cost-effective faecal indicator to monitor the public health impacts of faecal contamination. In contrast, consideration of faecal indicator decay is important when assessing dispersion and advection/dispersion dominant systems, which would pertain to transitional (estuarine) and coastal waterbodies. Results suggest that the inclusion of viral indicators, such as crAssphage and PMMoV, could improve the reliability of water quality modelling and minimise the risk of waterborne illnesses from faecal contamination.
Subject(s)
Hydrodynamics , Public Health , Water Quality , Bacteria , Bathing Beaches , Environmental Monitoring , Feces/microbiology , Reproducibility of Results , Water MicrobiologyABSTRACT
INTRODUCTION: It is widely acknowledged that cardiovascular diseases (CVDs) continue to be the leading cause of death globally. Furthermore, CVDs are the leading cause of diminished quality of life for patients, frequently as a result of their progressive deterioration. Medical implants that release drugs into the body are active implants that do more than just provide mechanical support; they also have a therapeutic role. Primarily, this is achieved through the controlled release of active pharmaceutical ingredients (API) at the implementation site. AREAS COVERED: In this review, the authors discuss drug-eluting stents, drug-eluting vascular grafts, and drug-eluting cardiac patches with the aim of providing a broad overview of the three most common types of cardiac implant. EXPERT OPINION: Drug eluting implants are an ideal alternative to traditional drug delivery because they allow for accurate drug release, local drug delivery to the target tissue, and minimize the adverse side effects associated with systemic administration. Despite the fact that there are still challenges that need to be addressed, the ever-evolving new technologies are making the fabrication of drug-eluting implants a rewarding therapeutic endeavor with the possibility for even greater advances.
Subject(s)
Cardiovascular Diseases , Drug-Eluting Stents , Humans , Cardiovascular Diseases/drug therapy , Pharmaceutical Preparations , Quality of Life , Drug Delivery Systems , Drug ImplantsABSTRACT
During April-July 2022, outbreaks of severe acute hepatitis of unknown etiology (SAHUE) were reported in 35 countries. Five percent of cases required liver transplantation, and 22 patients died. Viral metagenomic studies of clinical samples from SAHUE cases showed a correlation with human adenovirus F type 41 (HAdV-F41) and adeno-associated virus type 2 (AAV2). To explore the association between those DNA viruses and SAHUE in children in Ireland, we quantified HAdV-F41 and AAV2 in samples collected from a wastewater treatment plant serving 40% of Ireland's population. We noted a high correlation between HAdV-F41 and AAV2 circulation in the community and SAHUE clinical cases. Next-generation sequencing of the adenovirus hexon in wastewater demonstrated HAdV-F41 was the predominant HAdV type circulating. Our environmental analysis showed increased HAdV-F41 and AAV2 prevalence in the community during the SAHUE outbreak. Our findings highlight how wastewater sampling could aid in surveillance for respiratory adenovirus species.
Subject(s)
Adenovirus Infections, Human , Adenoviruses, Human , Hepatitis , Respiratory Tract Infections , Humans , Child , Wastewater , Ireland/epidemiology , Adenoviruses, Human/genetics , Hepatitis/epidemiology , Disease Outbreaks , Acute Disease , Adenovirus Infections, Human/epidemiology , Phylogeny , Respiratory Tract Infections/epidemiologyABSTRACT
The WHO recognises antimicrobial resistance (AMR) as a global health threat. The environment can act as a reservoir, facilitating the exchange and the physical movement of resistance. Aquatic environments are at particular risk of pollution, with large rivers subject to pollution from nearby human, industrial or agricultural activities. The land uses associated with these activities can influence the type of pollution. One type of pollution and a likely contributor to AMR pollution that lowers water quality is faecal pollution. Both pose an acute health risk and could have implications for resistance circulating in communities. The effects of land use are typically studied using physiochemical parameters or in isolation of one another. However, this study aimed to investigate the impact of different land uses on riverine systems. We explored whether differences in sources of faecal contamination are reflected in AMR gene concentrations across agricultural and urban areas. Water quality from three rivers impacted by different land uses was assessed over one year by quantifying faecal indicator bacteria (FIB), microbial source tracking markers (MST) and AMR genes. In addition, a multiparametric analysis of AMR gene pollution was carried out to understand whether agricultural and urban areas are similarly impacted. Faecal indicators varied greatly, with the highest levels of FIB and the human MST marker observed in urban regions. In addition, these faecal markers correlated with AMR genes. Similarly, significant correlations between the ruminant MST marker and AMR gene levels in agriculture areas were observed. Overall, applying multiparametric analyses to include AMR gene levels, separation and clustering of sites were seen based on land use characterisation. This study suggests that differences in prescription of antimicrobials used in animal and human healthcare may influence environmental resistomes across agricultural and urban areas. In addition, public health risks due to exposure to faecal contamination and AMR genes are highlighted.
Subject(s)
Anti-Bacterial Agents , Environmental Monitoring , Animals , Humans , Drug Resistance, Bacterial/genetics , Water Quality , Rivers , Bacteria , Feces/microbiology , Water Pollution , Water MicrobiologyABSTRACT
OBJECTIVES: Student assistantships are recommended to prepare medical graduates for clinical practice. Traditionally, assistantships have consisted of longer placements, often up to 15 weeks. However, within the constraints of the final year, medical schools need to carefully balance the time required for specialty placements, assessments and the risk of student burnout. We set out to evaluate the effectiveness of shorter, personalised student assistantships. DESIGN: An evaluative study on the changes in final year student confidence in preparedness for practice after a 3-week assistantship with defined learning objectives and learning needs assessment. SETTING: Eight hospitals affiliated with Imperial College School of Medicine. OUTCOMES: Student confidence in 10 learning outcomes including organising ward rounds, documentation, communication with colleagues, communication with patients and relatives, patient handover, practical procedures, patient management, acute care, prioritisation and out-of-hours clinical work. RESULTS: Two hundred and twenty final year medical students took part in the student assistantship, of whom 208 completed both the pre-assistantship and post-assistantship confidence rating questionnaires (95% completion rate). After the assistantship, 169 (81%) students expressed increased confidence levels in one or more learning objectives. For each individual learning objective, there was a significant change in the proportion of students who agreed or strongly agreed after the assistantship (p<0.0001). CONCLUSION: Overall, the focused 3-week, personalised student assistantships led to significant improvement across all learning objectives related to preparedness for practice. The use of the pre-assistantship confidence rating questionnaire allowed students to identify and target areas of learning needs during their assistantship.
Subject(s)
Education, Medical, Undergraduate , Students, Medical , Humans , London , Clinical Competence , Learning , HospitalsABSTRACT
BACKGROUND: Adults of advanced age, with functional dependency, socioeconomic disadvantage, or a need for home care, are expected to be at high risk of sarcopenia, frailty and malnutrition, yet are likely to be underrepresented in research. We aimed to explore the assessment of sarcopenia, frailty, and malnutrition in-home, and to describe the practicality of performing these assessments. METHODS: Home-based health assessments and post-study feedback surveys were conducted among community-dwelling older adults ≥65 years in receipt of state-funded home care (n = 31). Assessments included probable sarcopenia [hand-grip strength (HGS), chair rise-test, and SARC-F case-finding tool], the Mini Nutritional Assessment (MNA), and the Clinical Frailty Scale (CFS). RESULTS: The study group was of mean age 83.2 ± 8.2 years, 74% were female and 23% lived in socioeconomically disadvantaged areas. Almost all met the criteria for probable sarcopenia (94%, n = 29/31), were frail or vulnerable by the CFS (97%, n = 30/31), and over a quarter were at risk of malnutrition (26%, n = 8). Participants had low physical activity (71.0%, n = 22/31), with a mean daytime average of 11.4 ± 1.6 h spent sitting. It was possible to assess probable sarcopenia (by HGS and SARC-F, but not the chair rise test), malnutrition (MNA), and frailty (CFS). Home-based research was a complex environment, and unearthed significant unmet need, prompting referrals to health services (36%, n = 11), in addition to technology assistance. The majority of participants (93%) reported a willingness to partake in future research. CONCLUSIONS: Most community-dwelling older people in receipt of home support, assessed in this exploratory study, were at risk of probable sarcopenia, frailty, and low physical activity, with over a quarter were at risk of malnutrition. Our initial findings provide practical data for large scale studies and may inform the development of intervention studies aiming to support ageing in place.
Subject(s)
Frailty , Malnutrition , Sarcopenia , Female , Aged , Humans , Aged, 80 and over , Male , Independent Living , Geriatric Assessment , Cross-Sectional Studies , Frailty/epidemiology , Malnutrition/epidemiology , Sarcopenia/epidemiologyABSTRACT
Endogenous Cushing's syndrome (CS) poses considerable diagnostic challenges. Although late-night salivary cortisol (LNSC) is recommended as a first-line screening investigation, it remains the least widely used test in many countries. The combined measurement of LNSC and late-night salivary cortisone (LNS cortisone) has shown to further improve diagnostic accuracy. We present a retrospective study in a tertiary referral centre comparing LNSC, LNS cortisone, overnight dexamethasone suppression test, low-dose dexamethasone suppression test and 24-h urinary free cortisol results of patients investigated for CS. Patients were categorised into those who had CS (21 patients) and those who did not (33 patients). LNSC had a sensitivity of 95% and a specificity of 91%. LNS cortisone had a specificity of 100% and a sensitivity of 86%. With an optimal cut-off for LNS cortisone of >14.5 nmol/L the sensitivity was 95.2%, and the specificity was 100% with an area under the curve of 0.997, for diagnosing CS. Saliva collection is non-invasive and can be carried out at home. We therefore advocate simultaneous measurement of LNSC and LNS cortisone as the first-line screening test to evaluate patients with suspected CS.
ABSTRACT
SARS-CoV-2 RNA quantification in wastewater is an important tool for monitoring the prevalence of COVID-19 disease on a community scale which complements case-based surveillance systems. As novel variants of concern (VOCs) emerge there is also a need to identify the primary circulating variants in a community, accomplished to date by sequencing clinical samples. Quantifying variants in wastewater offers a cost-effective means to augment these sequencing efforts. In this study, SARS-CoV-2 N1 RNA concentrations and daily loadings were determined and compared to case-based data collected as part of a national surveillance programme to determine the validity of wastewater surveillance to monitor infection spread in the greater Dublin area. Further, sequencing of clinical samples was conducted to determine the primary SARS-CoV-2 lineages circulating in Dublin. Finally, digital PCR was employed to determine whether SARS-CoV-2 VOCs, Alpha and Delta, were quantifiable from wastewater. No lead or lag time was observed between SARS-CoV-2 wastewater and case-based data and SARS-CoV-2 trends in Dublin wastewater significantly correlated with the notification of confirmed cases through case-based surveillance preceding collection with a 5-day average. This demonstrates that viral RNA in Dublin's wastewater mirrors the spread of infection in the community. Clinical sequence data demonstrated that increased COVID-19 cases during Ireland's third wave coincided with the introduction of the Alpha variant, while the fourth wave coincided with increased prevalence of the Delta variant. Interestingly, the Alpha variant was detected in Dublin wastewater prior to the first genome being sequenced from clinical samples, while the Delta variant was identified at the same time in clinical and wastewater samples. This work demonstrates the validity of wastewater surveillance for monitoring SARS-CoV-2 infections and also highlights its effectiveness in identifying circulating variants which may prove useful when sequencing capacity is limited.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Humans , Ireland/epidemiology , RNA, Viral , SARS-CoV-2/genetics , Wastewater/analysis , Wastewater-Based Epidemiological MonitoringABSTRACT
Fecal pollution of surface water may introduce bacteria and bacteriophages harboring antibiotic resistance genes (ARGs) into the aquatic environment. Watercourses discharging into the marine environment, especially close to designated bathing waters, may expose recreational users to fecal pollution and therefore may increase the likelihood that they will be exposed to ARGs. This study compares the bacterial and bacteriophage ARG profiles of two rivers (River Tolka and Liffey) and two small urban streams (Elm Park and Trimleston Streams) that discharge close to two marine bathing waters in Dublin Bay. Despite the potential differences in pollution pressures experienced by these waterways, microbial source tracking analysis showed that the main source of pollution in both rivers and streams in the urban environment is human contamination. All ARGs included in this study, bla TEM , bla SHV , qnrS, and sul1, were present in all four waterways in both the bacterial and bacteriophage fractions, displaying a similar ARG profile. We show that nearshore marine bathing waters are strongly influenced by urban rivers and streams discharging into these, since they shared a similar ARG profile. In comparison to rivers and streams, the levels of bacterial ARGs were significantly reduced in the marine environment. In contrast, the bacteriophage ARG levels in freshwater and the marine were not significantly different. Nearshore marine bathing waters could therefore be a potential reservoir of bacteriophages carrying ARGs. In addition to being considered potential additional fecal indicators organism, bacteriophages may also be viewed as indicators of the spread of antimicrobial resistance.
ABSTRACT
Small urban streams discharging in the proximity of bathing waters may significantly contribute to the deterioration of water quality, yet their impact may be overlooked. This study focuses on the Elm Park stream in the city of Dublin that is subject to faecal contamination by unidentified sources. The aim of the study was to identify a minimum number of "sentinel" sampling stations in an urban catchment that would provide the maximum amount of information regarding faecal pollution in the catchment. Thus, high-resolution sampling within the catchment was carried out over the course of 1 year at 11 stations. Faecal indicator bacteria were enumerated and microbial source tracking (MST) was employed to evaluate human pollution. In addition, ammonium, total oxidised nitrogen, and phosphorus levels were monitored to determine if these correlated with faecal indicator and the HF183 MST marker. In addition, the effect of severe weather events on water quality was assessed using automated sampling at one of the identified "sentinel" stations during baseflow and high flow conditions over a 24-h period. Our results show that this urban stream is at times highly contaminated by point source faecal pollution and that human faecal pollution is pervasive in the catchment. Correlations between ammonium concentrations and faecal indicator bacteria (FIB) as well as the human MST marker were observed during the study. Cluster analysis identified four "sentinel" stations that provide sufficient information on faecal pollution in the stream, thus reducing the geographical complexity of the catchment. Furthermore, ammonium levels strongly correlated with FIB and the human HF183 MST marker under high flow conditions at key "sentinel" stations. This work demonstrates the effectiveness of pairing MST, faecal indicators, and ammonium monitoring to identify "sentinel" stations that could be more rapidly assessed using real-time ammonium readouts to assess remediation efforts.
ABSTRACT
The introduction of SARS-CoV-2 containing human stool and sewage into water bodies may raise public health concerns. However, assessment of public health risks by faecally contaminated water is limited by a lack of knowledge regarding the persistence of infectious SARS-CoV-2 in water. In the present study the decay rates of viable infectious SARS-CoV-2 and SARS-CoV-2 RNA were determined in river and seawater at 4 and 20°C. These decay rates were compared to S. typhimurium bacteriophage MS2 and pepper mild mottle virus (PMMoV). Persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in both freshwater and seawater at 4°C than at 20°C. T90 for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively. The T90 values were 1.1 days and 2.2 days in seawater at 20°C and 4°C, respectively. In contrast to the rapid inactivation of infectious SARS-CoV-2 in river and sea water, viral RNA was relatively stable. The RNA decay rates were increased in non-sterilised river and seawater, presumably due to the presence of microbiota. The decay rates of infectious MS2, MS2 RNA and PMMoV RNA differed significantly from the decay rate of SARS-CoV-2 RNA, suggesting that their use as surrogate markers for the persistence of SARS-CoV-2 in the environment is limited.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , RNA, Viral , Rivers , WastewaterABSTRACT
Bathing water quality may be negatively impacted by diffuse pollution arising from urban and agricultural activities and wildlife, it is therefore important to be able to differentiate between biological and geographical sources of faecal pollution. crAssphage was recently described as a novel human-associated microbial source tracking marker. This study aimed to evaluate the performance of the crAssphage marker in designated bathing waters. The sensitivity and specificity of the crAss_2 marker was evaluated using faecal samples from herring gulls, dogs, sewage and a stream impacted by human pollution (n = 80), which showed that all human impacted samples tested positive for the marker while none of the animal samples did. The crAss_2 marker was field tested in an urban marine bathing water close to the discharge point of human impacted streams. In addition, the bathing water is affected by dog and gull fouling. Analysis of water samples taken at the compliance point every 30 min during a tidal cycle following a rain event showed that the crAss_2 and HF183 markers performed equally well (Spearman correlation ρ = 0.84). The levels of these marker and faecal indicators (Escherichia coli, intestinal enterococci, somatic coliphages) varied by up to 2.5 log10 during the day. Analysis of a high-tide transect perpendicular to the shoreline revealed high levels of localised faecal contamination 1 km offshore, with a concomitant spike in the gull marker. In contrast, both the crAss_2 and HF183 markers remained at a constant level, showing that human faecal contamination is homogenously distributed, while gull pollution is localised. Performance of the crAss_2 and HF183 assay was further evaluated in bimonthly compliance point samples over an 18-month period. The co-occurrence between the crAss_2 and HF183 markers in compliance sampling was 76%. A combination of both markers should be applied in low pollution impacted environments to obtain a high confidence level.
Subject(s)
Environmental Monitoring , Water Microbiology , Animals , Dogs , Feces , Humans , Rivers , Sewage , Water Pollution/analysisABSTRACT
Cardiovascular diseases constitute a number of conditions which are the leading cause of death globally. To combat these diseases and improve the quality and duration of life, several cardiac implants have been developed, including stents, vascular grafts and valvular prostheses. The implantation of these vascular prosthesis has associated risks such as infection or blood clot formation. In order to overcome these limitations medicated vascular prosthesis have been previously used. The present paper describes a 3D printing method to develop medicated vascular prosthesis using fused deposition modelling (FDM) technology. For this purpose, rifampicin (RIF) was selected as a model molecule as it can be used to prevent vascular graft prosthesis infection. Thermoplastic polyurethane (TPU) and RIF were combined using hot melt extrusion (HME) to obtain filaments containing RIF concentrations ranging between 0 and 1% (w/w). These materials are capable of providing RIF release for periods ranging between 30 and 80 days. Moreover, TPU-based materials containing RIF were capable of inhibiting the growth of Staphylococcus aureus. This behaviour was observed even for TPU-based materials containing RIF concentrations of 0.1% (w/w). TPU containing 1% (w/w) of RIF showed antimicrobial properties even after 30 days of RIF release. Alternatively, these methods were used to prepare dipyridamole containing TPU filaments. Finally, using a dual extrusion 3D printer vascular grafts containing both drugs were prepared.