Direct Contamination Research Articles

Cave-adapted beetles from continental Portugal.

BackgroundThe cave biodiversity of continental Portugal faces tremendous conservation challenges, mostly linked to their direct destruction and contamination infiltrating from the surface. Beetles are the most diverse insects and one of the most diverse arthropod groups in caves of Portugal.New informationWe present the IUCN Red List profiles for the cave-adapted beetles from continental Portugal, all endemic to their respective geological units and massifs. Ground beetles (Carabidae) are the most diverse family of cave-adapted beetles in continental Portugal, followed by rove beetles (Staphylinidae). Beetles in caves of Portugal are mostly terrestrial and only one species is known to have evolved to live in groundwater. Trechus is the most diverse genus with four species, followed by Domene with three species and by Speonemadus and Iberoporus, both with one cave-adapted species. The aim of this contribution is to assess all endemic cave-adapted species of beetles from continental Portugal and to support their specific protection, to promote adequate management of surface habitats and the establishment of priority areas for conservation. The main biodiversity erosion drivers that are impacting the conservation of the studied species are pollution infiltrating from the surface, urbaniation, modifications of the natural habitat for touristic purposes and mining, quarrying and energy production infrastructures.This document can be used in spatial planning and territory management in karst, based on the current scientific knowledge.

COVID-19 Impacts on Beaches and Coastal Water Pollution at Selected Sites in Ecuador, and Management Proposals Post-pandemic

The COVID-19 pandemic has obliged Governments all around the world to implement confinement and social distancing measures. Leisure and business activities on beaches and in ports have restricted direct and indirect contamination from, for example, plastics, hydrocarbon spillage, microbiological loads, and noise levels. This has led to temporarily improved environmental conditions, and the beaches having conditions closer to Marine Protected Areas. Here we report some impacts that have been studied using local surveys and qualitative observations in Ecuador at the popular beaches and ports of Salinas, Manta, and Galapagos. Satellite data support this information. Online surveys were carried out at critical moments of the pandemic: May (15th) and just after when measures were relaxed a little, but within lockdown in July (21st) 2020. Respondents were asked to compare conditions before and during the pandemic lockdown. Most (97–99%) suggested that beaches had significantly improved from visual observations during confinement. On a scale from 1 (worst) to 5 (best), the beaches of Salinas and Manta respectively were rated 2.2 and 2.8 (less than acceptable) before quarantine, and 4.5 and 4.3 after; results from the second survey (after 18 weeks of restrictions) were much the same. Replies from Galapagos showed a similar trend but with less marked differences. In addition to the beaches having less plastic and garbage, more fish, and large marine organisms, including humpback whales (Megaptera novaeangliae), dolphin (bottlenose, Tursiops truncatus), and manta ray (Manta sp.) were observed near to shore. At Galapagos beaches, turtles, sea lions, and sharks were observed many more times than pre COVID. Quantitative satellite data on Chlorophyl and attenuation coefficient (Kd, 490 nm) support the qualitative survey data that there is an improvement in coastal environment quality. Here we recommend that this unique opportunity resulting from the COVID-19 pandemic is used locally, regionally and globally to construct baseline data sets that include information on physical, chemical, biological, and microbiological factors in coastal zones. These parameters can then help establish an effective Coastal Zone Management Plan based on beach description and quality (water standards, noise pollution), as well as the human dimension (tourist load, cultural heritage, and economic value indices). This data and information gathering ideally should be done before the beaches become more heavily used again as the pandemic recedes.

Implementation of a Low-Cost Method to Reduce Bacterial Load in Patient-Room Sink Drains

Background: Sink drains can act as breeding grounds for multidrug-resistant (MDR) bacteria, leading to outbreaks. Drains provide a protected humid environment where nutrient-rich substances are available. Recent and growing installation of water and energy conservation devices have led to increased frequency of drain blockage due to biofilm accumulation. Ineffective drainage may lead to backflow and accumulation of water in the sink during use, increasing the risk of contaminated aerosols formation or direct contamination of surrounding material and equipment. Cleaning and disinfection procedures of sink drains need to be improved to prevent amplification and dispersion of MDR bacteria. The objective of this study was to investigate alternatives to reduce the biofilm and risk of contamination through aerosols. Methods: Sink drains from patient rooms were randomly selected in the neonatal intensive care unit of a 450-bed pediatric hospital. We tested 4 approaches: (1) new drain; (2) self-disinfecting heating-vibration drain; (3) chemical disinfection with 20 ppm chlorine for 30 minutes; and (4) thermal disinfection with > 90°C water for 30 minutes. A special device was used during disinfection to increase the disinfectant contact time with the biofilm. Treatments were conducted weekly, with prior sampling of drain water. Other drains were also sampled weekly, including a control drain with no intervention. Bacterial loads were evaluated using flow cytometry and heterotrophic plate counts. The drains were made of stainless steel, a heat-conductive material. Results: Preliminary results show that chlorine disinfection had a small impact (<1 log) on culturable bacteria at 48 hours after disinfection but not after a week or repeated weekly disinfection. Thermal disinfection using boiling water is promising, showing an important decrease of 4 log in culturable cells after 48 hours and a concentration still 100× lower 1 week after the disinfection. Repeated weekly thermal disinfection maintained lower culturable levels in the drain. No culturable cells were detected in water from the self-disinfecting drain 2 months after installation, whereas the new drain became fully colonized to concentrations similar to those of drains prior to interventions during the same period. Conclusions: Thermal disinfection of drains is a promising alternative to chlorine. This solution is interesting because it is nontoxic and easy to perform, requiring a small volume of hot water. The rapid recolonization of the new drain suggests that replacing contaminated drains is not a sustainable solution and would need to be paired with a thermal disinfection program to maintain low culturable cells.Funding: NoDisclosures: None

Next-generation sequencing reveals wide genetic diversity of Blastocystis subtypes in chickens including potentially zoonotic subtypes.

Blastocystis sp. is an intestinal protist parasite commonly found in the feces of humans and animals worldwide. Blastocystis exhibits extensive genetic diversity and has been identified in humans and a variety of animals including other mammals and birds. Blastocystis subtypes do not exhibit strict host specificity which raises the possibility of zoonotic transmission through either direct contact or fecal contamination of food or water. However, reports detailing the subtypes and prevalence of Blastocystis in avian species are limited. Therefore, this study investigated the presence of Blastocystis in chickens by molecular characterization of the small subunit rRNA (SSU rRNA) gene. Fecal samples from 130 chickens were collected from local markets in Uberlândia and Belo Horizonte in the state of Minas Gerais, Brazil. To detect and identify subtypes of Blastocystis, a next-generation amplicon sequencing protocol was used. Forty-four of the 130 (33.8%) chickens examined were positive for Blastocystis. Blastocystis subtypes ST6 (23/130; 17.7%), ST7 (43/130; 33.1%), ST10 (1/130; 0.8%), ST14 (5/130; 3.8%), ST25 (1/130; 0.8%), and a novel subtype (ST29) (2/130; 1.5%) were observed. A nanopore sequencing strategy was used to obtain the near full-length SSU rRNA gene nucleotide sequence and validate novel subtype ST29. Mixed infections containing multiple subtypes were common and identified in 63.6% of Blastocystis-positive chickens. All positive samples contained one or both potentially zoonotic subtypes ST6 and ST7. The prevalence of Blastocystis in chickens was high, and molecular characterization mostly identified subtypes previously found in humans. Thus, chickens may be a source of human infection and environmental contamination.

Low mobility of CuO and TiO2 nanoparticles in agricultural soils of contrasting texture and organic matter content

The fate of nanoparticles (NPs) in soil under relevant environmental conditions is still poorly understood. In this study, the mobility of two metal-oxide nanoparticles (CuO and TiO2) in contrasting agricultural soils was investigated in water-saturated soil columns. The transport of TiO2 and CuO-NPs were assessed in six soils with three different textures (from sand to clay) and two contrasted organic matter (OM) contents for each texture. TiO2 mobility was very low in all soils, regardless of texture and OM content. Mass recoveries were always less than 5%, probably in relation with the strong homo-aggregation of TiO2-NPs observed in all soil solutions, with apparent sizes 3–6 times larger than their nominal size. This low mobility suggests that TiO2-NPs present a low risk of direct groundwater contamination in contrasted surface soils. Although their retention was also generally high (more than 86%), CuO nanoparticles were found to be mobile in all soils. This is probably related to their smaller apparent size and low capacity of homo-aggregation of CuO-NPs in all soil solutions. No clear influence of neither soil texture or soil total organic matter content could be observed on CuO transport. However, this study shows that in contrasted agricultural soils, CuO-NPs transport is mainly controlled by the solutes dissolved in soil solution (DOC and PO4 species), rather than by the properties of the soil solid phase.

Rearing system with nurse cows and risk factors for Cryptosporidium infection in organic dairy calves

Rearing dairy calves with nurse cows has been increasingly adopted by French farmers especially in organic farming and is characterized by a fostering of two to four calves during the first month of life by an unmilked lactating cow. This type of rearing remains poorly documented regarding its impact on calf health, such as cryptosporidiosis. The objectives of our study were to describe practices related to rearing dairy calves with nurse cows and to evaluate the prevalence, intensity and risk factors for Cryptosporidium infection in calf neonates. Between January and September 2019, the rearing practices of calves were described in 20 organic French farms and faeces were sampled once from 611 animals aged between 5 and 21 days. Cryptosporidium oocyst shedding was identified by modified Ziehl-Neelsen technique and scored semi-quantitatively (score 0–4). The risk of excretion (score 0 versus 1–4) was analysed using multivariate logistic regression models.This cow-calf rearing system usually consisted of a first phase with the dam, followed by an optional phase of artificial milk feeding (calves being fed with whole milk of the farm) and a final phase of fostering by a nurse cow. Each nurse was suckled from one to five calves of close age with a fostering age of 8 days on average. The oocyst shedding prevalence was 40.2 % and similar to classically reared calves, but the intensity of shedding and the prevalence of diarrhoea appeared to be lower. The identified six risk factors for oocyst shedding were: born in the last two thirds of the birth order, born between January and July versus August and September, calf with its dam in the barn versus on pasture, having an artificial milk feeding phase versus being with the dam only, and contact between peer calves and notably the presence of an oocyst excretory calf fostered by the same nurse. These results emphasize the role of the environment for the direct and indirect contamination, particularly that related to the accumulation of oocysts from previous or peer calves facilitating the faecal-oral route of transmission. This highlights the crucial role of the premises used intensively during the winter and spring months with higher densities of calves in the barn compared to outdoor situations promoted by this rearing.

Surgical Field Isolation Through Rubber Dam to Prevent COVID-19 Exposure During Tooth Extraction: Case Report

Background: At the beginning of 2020, a new pathogen named SARS-CoV-2 spread from China to the globe, becoming responsible for a potentially lethal acute respiratory syndrome: COVID-19. Direct contact and airborne contamination are the most frequent infection ways of SARS-CoV-2. During routine dental practice, SARS-CoV-2 transmission can occur through direct contact with mucous membranes, oral fluids, and contaminated instruments or inhalation of aerosol from infected patients. Introduction: Tooth extraction often involves exposure to blood and oral fluids, and the use of a rubber dam could be indicated to minimize direct contact and to decrease the amount of potentially infected droplets around the operatory field. The aim of this clinical case is to show how the use of a rubber dam could help in preventing or minimizing COVID-19 exposure during dental extraction. Materials and Methods: A 32-year-old patient reported severe pain and discomfort to an upper first molar due to a deep carious lesion and vertical tooth fracture. Under local anaesthesia, a rubber dam was placed, isolating the whole upper right sextant, and an atraumatic extraction was performed. Results: All three roots were intact, the bone septum was stable, and no oro-antral communication was present. A gauze swab was placed onto the socket and compressed slightly. After 5 minutes, the socket stopped bleeding, and both clamp and rubber dam, were removed. Conclusion: Within the limits of this single case report, the use rubber dam prior to tooth extraction could be a useful device to decrease aerosol spread and exposure to blood.

Evaluation of arsenic contamination and potential health risk through water intake in urban and rural areas

Arsenic (As) is a global public health and environmental problem because of its non-degradable and toxic nature. This study was carried out to assess the As contamination and potential health risk through water intake in rural and urban areas. Water samples were collected from urban and rural areas of Kahror Pacca, Punjab, Pakistan, and then, analyzed for As concentration. The concentrations of As in water samples were 1.62 − 35.28 and 3.23 − 45.62 μg/L for the rural and urban areas, respectively. The spatial distribution of As-rich shallow groundwater specifies their direct contamination through anthropogenic influence and agricultural practices. The chronic risk exposure was evaluated based on the determined As through hazard quotient, average daily dose, and cancer risk. Results disclosed that hazard quotient values were > 1 in studied drinking water samples. The cancer risk due to As consumption surpassed the threshold limits defined by the United States environmental protection agency (1.0E-04 to 1.0E06). Statistical analyses, including principal component analyses and Pearson correlation, suggested that As contamination in drinking water was imputed to both geogenic and anthropogenic reasons. It is revealed that intake of As contaminated water might result in various cancer problems to the community in the future. Research Highlights Arsenic concentration surpassed WHO drinking water guidelines Arsenic has hazard quotient values > 1 through electric pump water consumption Statistical analysis revealed geogenic and anthropogenic activities contributed to water contamination

Understanding the effect of oil on phytoremediation of PCB co-contamination in transformer oil using Chromolaena odorata

Greenhouse assessment of the effect of oil on Chromolaena odorata ability to remove PCB from soil treated with transformer oil co-contaminated with Aroclor 1260 was done. Plants were transplanted into one kilogram of soil contained in 1 L pots differently containing 100, 200, and 500 ml of transformer oil (T/O), co-contaminated with 100 ppm of Aroclor. Treatments were done in two microcosms; direct contamination and soil cultured method. Measured plant growth parameters showed that C. odorata growth was affected by the different concentrations of oil. Inhibition of plant growth by oil increased with concentrations. At the end of six weeks, plant growth was affected in T/O amended soil. Plants size was increased by 1.4, 0.46 and −1.0% in direct treatment and 17.01, 6.09 and 1.08% in soil culture at the 100, 200 and 500 ppm respectively. Untreated control showed a 43.07% increase. Slight PCB recovery was observed in root tissues of C. odorata but soil PCB was reduced by 66.6, 53.2, 41.5% and 77.3, 74.7, 58.8% at both treatments in their respective concentrations of oil. However, unplanted control was reduced by 21.4 and 16.7% in the two treatments at 66,000 ppm of oil. This study has shown that with improved agronomic practices, there is a possibility of phytoremediation of soil PCB from PCB contained transformer oil contaminated soil using Chromolaena odorata, hence it should be optimized in the field.

Potential Role of Lycopene in the Inhibition of Di(2-ethylhexyl) Phthalate-Induced Ferroptosis in Spleen Via Modulation of Iron Ion Homeostasis.

Di(2-ethylhexyl) phthalate (DEHP) is a synthetic chemical and widely used as a plasticizer. Humans can be exposed to DEHP through direct contact or environmental contamination. Lycopene (Lyc) has been discussed as a potential effector in the prevention and therapy of various diseases. 140 male mice were assigned into control, vehicle control, Lyc (5 mg/kg BW/d), DEHP (500 and 1000 mg/kg BW/d, respectively), and DEHP + Lyc groups and treated with an oral gavage that lasted 28 d. The ultrastructural results showed that DEHP induced pathological changes and mitochondrial injuries. We further revealed that DEHP exposure destroyed the Fe2+ imbalance homeostasis and, consequently, increases of lipid peroxidation and inhibition of cysteine/glutamate antiporter, all of which were involved in the process of ferroptsis. Moreover, the supplementation of Lyc significantly inhibited the ferroptsis changes mentioned above. Altogether, these results indicated that DEHP exposure triggered splenic cell death via ferroptosis; meanwhile, they also shed new evidence on a potential clue for the intervention and prevention of DEHP-related diseases.

Classification of aflatoxin B1 naturally contaminated peanut using visible and near-infrared hyperspectral imaging by integrating spectral and texture features

The aim of this study is to carry out a non-destructive, hyperspectral imaging-based method to discriminate between normal and naturally aflatoxin B1 (AFB1) contaminated peanuts. Two varieties of peanut were imaged under a hyperspectral imaging system in the spectral range from 400 to 1000 nm. The reference AFB1 levels were measured by enzyme linked immunosorbentassay(ELISA) method, then the peanuts were divided into two categories according to the threshold of 20 ppb. The spectral, color and texture features were extracted and integrated to discriminate AFB1 contaminated from normal peanuts. Different pretreatment methods were conducted on the full spectra, the linear discriminant analysis (LDA) results indicated that firstly Savitzky-Golay smoothing (SGS) then standard normal transformation (SNV) could achieve the best discrimination with an accuracy of 90% and 92% for calibration and validation sets respectively. The LDA results of feature integration proved that the optimized spectral features combined with the texture features realized the best classification, with an accuracy of 91% and 94% for calibration and validation sets respectively. Finally, the performance of partial least squares discrimination analysis (PLS-DA) and support vector machine (SVM) was compared with the LDA, the SVM with RBF kernel revealed the best results with an accuracy of 93% and 94% for calibration and validation sets respectively. This study presented the potential of hyperspectral imaging in direct AFB1 contamination classification of peanut, and demonstrated that the combination of texture and spectra features could improve the modelling results.

Polycyclic Aromatic Hydrocarbons, Mercury and Arsenic Content in Soils of Larsemann Hills, Pravda Coast and Fulmar Island, Eastern Antarctica.

This study is aimed at investigation of various potential contaminants (arsenic, mercury and polycyclic aromatic hydrocarbons) content in soils of different landscapes of Eastern Antarctica ice-free areas. Our data not only showed that intensive human impact might result in significant direct contamination of surrounding landforms, but also revealed a specific role of ornithogenic transport in distribution of contaminants. Analysis revealed that the contents of investigated elements were 0.100-8.055mgkg-1 (arsenic), 0.025-0.027mgkg-1 (mercury) in Larsemann Hills and 0.100-1.213mgkg-1 (arsenic), 0.023-0.593mgkg-1 (mercury) in vicinities of Mirny station and Fulmar Island. Accumulation of some elements in guano-derived and moss materials lead to higher values of other soil pollution indices at natural sites. Results of our study revealed the predominance of light molecular weight PAHs (fluorene and acenaphthylene) in studied soils. Results of our study are not completely in agreement with the idea of an practically uncontaminated Antarctic ecosystem which was previously reported for Eastern Antarctica ice-free areas. Various human activities carried out at local scale have been found to be responsible for increase of metal levels in studied Antarctic environments.

Pleural empyema from the point of view of a thoracic surgeon

Background. Pleural empyema (PE) is the presence of pus in the pleural cavity. The causes of PE include the diseases of adjacent organs (75 %), direct contamination of the pleural cavity during injuries or operations (20 %), and hematogenous dissemination of infection (5 %).
 Objective. To describe the modern views on the treatment of EP.
 Materials and methods. Analysis of literature sources on this topic.
 Results and discussion. Radiography, computed tomography, and ultrasound can be used to diagnose PE. To detect PE, radiography should always be performed in two projections, paying special attention to the posterior sinus and the space above the diaphragm. Computed tomography shows pleural layers’ separation and a “pregnant woman” symptom. Ultrasound can distinguish fluid, pleural thickening and pulmonary infiltration, as well as determine the optimal point for puncture. The ultimate goals of PE treatment include the obliteration of the pleural cavity or creating conditions for the formation of a sterile residual cavity. In case of acute PE, drainage, washing, and antibiotic therapy are applied; correction of concomitant diseases is carried out. Drainage of the pleural cavity should be preceded by a puncture of the pleural cavity to obtain pathological contents. The appearance and odor of the fluid obtained by puncture are the most important indicators of the pathology. Drainage can be performed at the point where the pus was obtained, or in the VII-VIII hypochondrium along the posterior axillary line. Drains from polyvinylchloride with a diameter of 6-8 mm are applied. The length depends on the task. Videothoracoscopy is a modern method of treating PE. This method is minimally invasive, removes fibrin and pus, destroys adhesions, connects cavities and provides drainage at the optimal point. To wash the pleural cavity, it is advisable to use decamethoxine or povidone-iodine. With regard to antibiotic therapy, levofloxacin or third-generation cephalosporins are used in combination with an antianaerobic drug, or carbapenems or glycopeptides.
 Conclusions. 1. PE is often a secondary infectious process caused by adjacent structures’ infection. 2. Pleural cavity sanitation during videothoracoscopy and drainage are the main methods of PE treatment. 3. Antibiotic therapy and pleural lavage are integral components of PE treatment.

Particulate Mercury and Particulate Organic Matter in the Itenez Basin (Bolivia)

In rivers and other freshwater bodies, the presence of mercury can be due to direct contamination by anthropic activities such as gold mining. However, it can also be attributed to atmospheric deposition and erosion, runoff, or lixiviation from surrounding soils. In the case of the Amazon rainforest, high mercury contents have been reported for litter and topsoil, which could affect the mercury concentrations in water bodies. Samples of suspended particulate matter were obtained from a transect of the Itenez River, associated lakes, and some of its tributaries. The aim was to obtain information on particulate mercury’s origin in the study area and determine the relationship between particulate mercury and particulate organic carbon. The concentration of mercury, organic matter, and the C:N ratio of the suspended matter was determined. The concentration of particulate mercury by water volume depended on changes in suspended matter loads, which in turn were mostly affected by the nature of the watershed or sediment resuspension. The observed values for the percentage of organic matter and the C:N ratio suggest that most of the mercury content in rivers and lakes originated from soils. A positive correlation was found between mercury concentration by weight of particulate matter and organic carbon content in particles. This correlation might be due to the direct binding of mercury to organic matter through functional groups like thiols or to an indirect effect of oxyhydroxides that can adsorb mercury and are associated with organic matter.

A comprehensive review of saline effluent disposal and treatment: conventional practices, emerging technologies, and future potential

Abstract An ever-increasing volume of saline effluents from industries, oil–gas fields, and desalination plants has resulted in an enormous amount of pollutants with undesirable effects on the environment and human health. Adequate disposal and treatment of these effluents remains a persistent problem and poses significant technical as well as economic challenges. Saline effluents can have considerable environmental impacts, depending upon the sensitivity of the surrounding ecosystems. Conventional disposal techniques mostly suffer from direct or indirect contamination of water/soil and are no longer preferred. As a result, several advanced treatment methods are being considered for sustainable saline effluent management in recent times. In this context, a comprehensive and updated review of conventional methods, along with emerging technologies for disposal and treatment of saline effluent, is presented. Existing treatment approaches, including membrane operation, thermal processes, chemical techniques, and biological methods, are discussed. The application of innovative hybrid processes (combining two or more treatment methods) aiming at lower energy demand and higher treatment efficiency has also been evaluated. Subsequently, emerging sustainable strategies like waste minimization and water recovery, zero liquid discharge, and resource recovery for saline effluents have been examined. The prospect of integrating the renewable energy sources with energy-intensive saline treatment methods towards energy–water–environment nexus is also explored.

Successful Management of a Giant Mycotic Coronary Artery Aneurysm Develeped after Multivessel PCI with Drug-Eluting Stent

Coronary artery stent infection has been reported with both bare metal stent and drug eluting stent and can present as mycotic coronary artery aneurysm, pseudoaneurysm. myocardial abscess, pericarditis or exudative effusion. Infection at the site of coronary stent implantation is rare and is believed to result typically from either direct stent contamination at the time of delivery or transient bacteraemia from access site. Recently, several case reports of pseudoaneurysm formation after DES implantation have been reported in the literature. We describe the successful surgical management of giant mycotic pseudoaneurysm of RCA presenting as fever of unknown origin with AMI (inferior) three months after multivessel PCI in LAD & RCA with DES in radial route. This report illustrates the importance of early detection and prompt management of these rare coronary pseudoaneurysms, which is a highly lethal condition. At three months follow-up after surgery, the patient was asymptomatic with fair LVEF 58%
 Bangladesh Heart Journal 2020; 35(1) : 66-70

Immobilizing hydrolytic active Papain on biodegradable PLLA for biofilm inhibition in cardiovascular applications

Abstract The use of biomaterials in medicine is becoming increasingly important. One of the main concerns is the foreign body associated infection caused by direct microbial contamination or clinical infections. The bacterial biofilm formation on biomaterials depends on their surface properties. Therefore, several anti-adhesive surface modifications were developed. Nevertheless, the demand for antimicrobial agents that prevent bacterial colonisation is still largely unmet. The immobilization of active antimicrobial agents, such as antibacterial peptides or enzymes, offers a potential approach to achieve long-lasting effectiveness. In this investigation, the hydrolytic enzyme papain with its published antibacterial activity was covalently immobilized on the well-established biodegradable biomaterial poly-L-lactic acid (PLLA). For the characterization of the enzymes on the PLLA surfaces, the protein content and enzyme activity were determined. A biofilm assay was performed to test the effect of the papain-modified PLLA samples on the biofilm-forming bacterial strain Clostridioides difficile, one of the most frequently occurring human nosocomial pathogens. The investigated hydrolytic enzyme papain could be immobilized by coupling via the crosslinker EDC to the PLLA surface. Detection was performed by determination of the amount of protein and the reduced biofilm growth after 24 h and 72 h compared to the reference.

Isolation through rubber dam to prevent COVID-19 exposure during flapless trans-crestal sinus lift procedures.

In 2020, a highly infective new pathogen (Sars-CoV-2) spread from China to the whole globe, and became responsible of an acute respiratory syndrome, often asymptomatic but potentially lethal, named COVID-19. Airborne and direct contact contamination are the major infection pathways of Sars-CoV-2 and it has been shown that virus spread can also happen in absence of clinical symptoms. SARS-CoV-2 transmission during dental procedures can happen through inhalation of droplets from infected patients or direct contact with mucous membranes, oral fluids, and contaminated instruments. Both sinus lift and implant surgeries often involve bleeding and exposure to oral fluids, and a rubber dam could be used to reduce direct contact and the amount of potentially infected aerosol. The aim of this short case presentation is to illustrate how the use of a rubber dam could be extremely useful in preventing COVID-19 exposure during flapless trans-crestal sinus lift procedures.

Trace element soil contamination from smelters in the Illawarra region, New South Wales, Australia

This study investigated the regional distribution of trace elements in 395 soil samples in the vicinity of the industrial complex of Port Kembla, New South Wales, Australia, which comprises former lead and copper smelters, an integrated steelworks and associated industries. Total trace element concentrations in the soil samples showed the extent of contamination by Cu, Pb, Zn, Ni, As, Se, Sn and Sb was greatest in samples located close to the Port Kembla copper smelter stack and the Kanahooka lead smelter, indicating direct contamination due to anthropogenic activities. The mean enrichment factors for the eight trace elements ranged from 1 to 6 × background, but the maximum concentrations ranged from 15 to 78 × background. Soil samples from highly contaminated areas, that exceed the acceptable total trace element ranges in ANZECC and ARMCANZ sediment quality guidelines, pose a significant potential health risk and require further environmental assessment for bioavailability.

Abstract A20: Dietary ingestion of aristolochic acid: Mechanisms of exposure

Abstract Aristolochic acids (AA) are human carcinogens and nephrotoxins found in Aristolochia plants, including herbs used in traditional medicines throughout the world. Aristolochic acids can also be ingested as an environmental contaminant in food, which forms the basis of Balkan endemic nephropathy and associated upper tract urothelial cancer. Aristolactam DNA-adducts, formed after metabolism of AA, are promutagenic and are resistant to repair and readily detected in human tissue sample DNA decades after exposure. Thus, AL-DNA adducts are excellent biomarkers of exposure to this carcinogen. The mutational signature of AA is distinct for an environmental carcinogen and is recognized as Signature 22 in the COSMIC mutational signature database. Molecular epidemiology using the presence of adducts and/or the presence of Signature 22 has implicated AA in the etiology of several cancers, including upper-tract urothelial cancer, bladder cancer, renal cell clear cell carcinoma, hepatocellular carcinoma, and cholangiocarcinomas. In regions of the world reliant on traditional medicines, including much of Asia, the AA contribution to incidence of these cancers is significant. In the Balkan countries of Europe, the route of exposure is thought to occur via contamination of wheat harvests with Aristolochia plant material from weed growth. In endemic villages farming families traditionally have ingested primarily wheat flour milled from their own harvests. An alternative hypothesis is that decaying Aristolochia plants release the chemically stable aristolochic acids into the soil, and these are then taken up and concentrated by food plants. To distinguish between these hypotheses, we have obtained 25 flour samples from individual farms along the Croatia/Bosnia and Herzegovina border. To identify AA-contaminated flour, aristolochic acids were extracted from aliquots of the flour, reduced to aristolactams, and quantitated with an LC-ESI-MS/MS method. Several flour samples were indeed contaminated with AA in the range of 10–100 parts per billion. Secondly, we also extracted DNA from each flour sample. The direct contamination hypothesis predicts the presence of Aristolochia DNA in contaminated flour samples; the indirect contamination via decay hypothesis does not. Using widely accepted plant “barcode” PCR protocols, we amplified a portion of the rbcLa gene with generic primers that amplify the gene from all species. Within this PCR amplicon each plant species has a constellation of specific base-pairs. Thus, the contribution of all plant species to the flour sample can be determined by highly parallel sequencing of the amplicon. We will present the results of this next-gen sequencing to determine the contribution of Aristolochia to Balkan flour samples and correlation with aristolochic acid content. Citation Format: Viktoriya Sidorenko, Robert Rieger, Bojan Jelakovic, Thomas Rosenquist. Dietary ingestion of aristolochic acid: Mechanisms of exposure [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr A20.