Artificial Soil Test Research Articles

Toxicological effects induced by two carbamates on earthworms (Eisenia fetida): Acute toxicity, arrested regeneration and underlying mechanisms

Eisenia fetida is recognised as advantageous model species in ecotoxicological and regeneration investigations. The intensive utilization of carbamate pesticides (CARs) imposes heavy residue burdens and grave hazards on edaphic environments as well as soil fauna therein. However, precise mechanisms whereby the specific CAR exerted toxic effects on earthworms remain largely elusive, notably from regenerative perspective. Herein, acute responses and regenerative toxicity of two carbamates (metolcarb, MEB and fenoxycarb, FEB) against E. fetida were dissected using biochemical, histological as well as molecular approaches following OECD guidelines at the cellular, tissue and organismal level. The acute toxicity data implied that MEB/FEB were very toxic/medium to extremely toxic, respectively in filter paper contact test and low to medium toxic/low toxic, respectively in artificial soil test. Chronic exposure to MEB and FEB at sublethal concentrations significantly mitigated the soluble protein content, protein abundance while enhanced the protein carbonylation level. Moreover, severely retarded posterior renewal of amputated earthworms was noticed in MEB and FEB treatments relative to the control group, with pronouncedly compromised morphology, dwindling segments and elevated cell apoptosis of blastema tissues, which were mediated by the rising Sox2 and decreasing TCTP levels. Taken together, these findings not only presented baseline toxicity cues for MEB and FEB exposure against earthworms, but also yielded mechanistic insights into regenerative toxicity upon CAR exposure, further contributing to the environmental risk assessment and benchmark formulation of agrochemical pollution in terrestrial ecosystem.

Investigation of the efficacy of an innovative endoscope drying and storage method in a simulated ERCP setting.

Background and study aims Drying after cleaning and disinfection is essential in the reprocessing of endoscopes since microorganisms can grow and form biofilms on wet surfaces. In this experimental non-clinical study, we investigated the efficacy of a novel, fast-drying method when reprocessing duodenoscopes. Methods During a series of 40 tests, three duodenoscopes were exposed to an artificial test soil containing supraphysiological loads of four types of gut microorganisms in a non-clinical ERCP simulation, followed by reprocessing and drying with the PlasmaTYPHOON. Cultures of the distal tip and working channel were acquired immediately after automated decontamination and after drying with the PlasmaTYPHOON. Cobalt chloride paper tests and borescope inspections were used to evaluate drying efficacy. Results Contamination of the working channels dropped from 86.4 % post-decontamination to 33.6 % post-drying, with 94 % of the positive post-drying samples belonging to one duodenoscope. This duodenoscope showed persistent contamination with P. aeruginosa in the working channel. The other two duodenoscopes only showed low levels of P. aeruginosa in post-decontamination channel samples, but not after drying. Cobalt chloride paper tests and borescope inspections revealed good drying efficacy. Conclusions Positive cultures for gut microorganisms were often found in wet endoscopes post-decontamination. The PlasmaTYPHOON is an effective fast-drying method capable of abolishing nearly all remaining microorganisms after decontamination provided no biofilm has developed, even when using a supraphysiological concentration of bacterial load. The clinical use of the PlasmaTYPHOON has the potential to reduce endoscope contamination, the use of wet contaminated endoscopes and therefore the risk of patient infection.

Effective cleaning and decontamination of the internal air and water channels, heads and head-gears of multiple contra-angle dental handpieces using an enzymatic detergent and automated washer-disinfection in a dental hospital setting

Dental handpieces (DHPs) are reusable invasive medical devices that must be cleaned, decontaminated, lubricated and steam sterilized after use. DHPs have a complex internal design including narrow channels, contamination of which can compromise sterilization. DHPs are not designed for routine disassembly, making cleaning/decontamination efficacy difficult to monitor. Washer-disinfection is the preferred method of decontaminating DHPs, but few studies have investigated its direct effectiveness at reducing microbial contamination internally. To use contra-angle DHPs as a model system to investigate the effectiveness of washer-disinfection at reducing microbial contamination of internal components of multiple DHPs. The air and water channels and heads of 10 disassembled contra-angle DHPs (BienAir, Biel/Bienne, Switzerland) were inoculated separately with 108 colony forming units (cfu) of Pseudomanas aeruginosa, Staphylococcus aureus, Enterococcus hirae or Candida albicans in the presence of 0.3% bovine serum albumin (BSA) (clean conditions), 3.0% BSA or 10% artificial test soil (dirty conditions). After reassembly, all 10 DHPs underwent washer-disinfection simultaneously in a Míele (Míele Ireland Ltd., Dublin, Ireland) PG8528 washer-disinfector and were tested for reductions in micro-organisms and protein. Additional experiments were undertaken with three lubricated DHPs inoculated with S.aureus and 10% test soil. All experiments were repeated in triplicate. On average, an approximate 5 log or greater reduction in microbial cfu and a >93% reduction in protein from DHP heads and channels was consistently recorded following washer-disinfection for all DHPs under all conditions tested. The internal components of multiple DHPs can be effectively cleaned and decontaminated by washer-disinfection.

The Survival Response of Earthworm (Eisenia fetida L.) to Individual and Binary Mixtures of Herbicides.

Frequent use of herbicides may impose a risk on non-target species. The objective was to test the combined toxic effect of binary herbicide mixtures—metribuzin:halosulfuron and metribuzin:flumioxazin—on non-target earthworms in two test systems: filter paper and a soil toxicity test system. The joint action experiments were independently run twice to substantiate the findings. The most potent individual herbicide was metribuzin, with a 50% lethal concentration (LC50) of 17.17 µg ai. cm−2 at 48 h in the filter paper test. The toxicity of the individual herbicides on the filter paper test was ranked as metribuzin>halosulfuron>flumioxazin. In the soil test, metribuzin and halosulfuron had high toxicity with an LC50 of 8.48 and 10.08 mg ai. kg−1, respectively, on day 14. Thus, the individual herbicide ranking did not change between the filter paper and artificial soil tests. The herbicide’s mixed effect in both test systems showed a consistent antagonistic effect relative to a Concentration Addition reference model. It indicates that the mixtures retracted the herbicide’s action in the earthworms.

A standardized method for evaluating test soils used to demonstrate cleaning efficacy

Cleaning and associated validation requirements are essential for the safe use of reusable devices. In the past, test methods and associated endpoints for cleaning validations have varied worldwide. Recent international standards have updated the requirements to include cleaning endpoints and requirements for the use of test soils for demonstrating cleaning efficacy of washer-disinfectors. A quantitative comparison of test soils used in cleaning efficacy studies was conducted using a new standardized test method as published in Annexe B ISO 15883-5:2021. Test soils included Artificial Test Soil (ATS 2015), Blood Test Soil (BTS), Coagulated Blood, Defibrinated Blood Soil (DBLSO), Modified Coagulated Blood Soil, Two Component Blood Test Soil and the UK Test Soil (Edinburgh Soil). All the test soils demonstrated acceptable performance in accordance with the standard.

Factors influencing environmental sampling recovery of healthcare pathogens from non-porous surfaces with cellulose sponges.

Results from sampling healthcare surfaces for pathogens are difficult to interpret without understanding the factors that influence pathogen detection. We investigated the recovery of four healthcare-associated pathogens from three common surface materials, and how a body fluid simulant (artificial test soil, ATS), deposition method, and contamination levels influence the percent of organisms recovered (%R). Known quantities of carbapenemase-producing KPC+ Klebsiella pneumoniae (KPC), Acinetobacter baumannii, vancomycin-resistant Enterococcus faecalis, and Clostridioides difficile spores (CD) were suspended in Butterfield’s buffer or ATS, deposited on 323cm2 steel, plastic, and laminate surfaces, allowed to dry 1h, then sampled with a cellulose sponge wipe. Bacteria were eluted, cultured, CFU counted and %R determined relative to the inoculum. The %R varied by organism, from <1% (KPC) to almost 60% (CD) and was more dependent upon the organism’s characteristics and presence of ATS than on surface type. KPC persistence as determined by culture also declined by >1 log10 within the 60 min drying time. For all organisms, the %R was significantly greater if suspended in ATS than if suspended in Butterfield’s buffer (p<0.05), and for most organisms the %R was not significantly different when sampled from any of the three surfaces. Organisms deposited in multiple droplets were recovered at equal or higher %R than if spread evenly on the surface. This work assists in interpreting data collected while investigating a healthcare infection outbreak or while conducting infection intervention studies.

Selenium toxicity, bioaccumulation, and distribution in earthworms (Eisenia fetida) exposed to different substrates

Selenium (Se) is an essential microelement for human or animal health. At high concentrations, it can cause Se poisoning. Human activities (such as coal burning and mining) threaten soil biota by mobilizing high levels of Se. We used the earthworm Eisenia fetida as a bio-indicator of environmental pollutants to investigate Se acute toxicity, enrichment, and distribution through exposure tests using filter paper, artificial soil and cow manure. The 24 h- and 48 h-LC50 for the filter paper contact test were 2.7 and 1.52 μg/cm2. In artificial soil test, the 14 d-LC50 and 14 d-biomass inhibition concentration (IC20) were 63.86 and 59.81 mg/kg, respectively. The cow manure resulted in a 2.2- and 2.6-fold higher LC50 and IC20 than artificial soil results, respectively. Earthworms accumulated the largest Se load (89.47 mg/kg) in artificial soil containing 80 mg Se/kg and only accumulated 90.3 mg/kg in cow manure containing 160 mg Se/kg; 46.6–60.59% of the total Se was distributed in the tail of E. fetida. The Se enrichment rate (SERSe) and bioaccumulation factor (BAFSe) scored higher in artificial soil than in cow manure with the same Se concentration exposure, and the highest SERSe was 6.21 and 6.31 mg Se/kg earthworm/d, respectively. The highest BAFSe was 1.49 in artificial soil and 0.75 in cow manure. Our results demonstrate that selenite is more toxic to earthworms living in artificial soil than in cow manure. E. fetida possesses certain Se detoxification mechanisms by distributing Se in the tail.

Effects of bisphenol S on the life cycle of earthworms and its assessment in the context of climate change

Two of the main challenges facing soil organisms nowadays are emerging contaminants and climate change. The biosolids used in agriculture can contain xenobiotics, such as bisphenols, not regulated in soil. The proven harmful effect of bisphenol A (BPA) has urged the search for replacements such as bisphenol S (BPS) but no studies have tested the effects of this substitute on soil organisms. Our aim was to study the impacts of BPS on the biological cycle of two earthworm species, Dendrobaena veneta and Eisenia fetida, and compare to earlier results with BPA to confirm its suitability as replacement. Moreover, interactions with temperature were investigated, the increase of which is expected due to climate change. Sublethal concentrations (10, 100, 1000 mg kg−1) were evaluated by an artificial soil test at 21 °C. Additional tests with D. veneta were performed at 26 °C, to observe whether a 5 °C increase affected the toxicity of BPS in earthworms. In E. fetida, reproduction (number of juveniles and cocoons) was negatively affected by BPS but growth was not negatively impacted. In D. veneta reproduction was not affected and greater growth was detected in the lowest concentration tested only at 26 °C. Increase in temperature showed no interaction on BPS toxicity but had a greater negative impact than the toxicant and adults showed significantly lower growth and reproductive rate at 26 °C. A direct contact test with BPS was performed to evaluate mortality and enzymatic activity of glutathione-S-transferase (GST). The measured enzymatic activity was higher with increasing concentration of BPS at 48 h and 21 °C in D. veneta but not in E. fetida or at 26 °C. Our results suggest that BPS is slightly less toxic than BPA supporting its use as alternative and also highlight the harmful effects that an increase in temperature can have in earthworm populations, exceeding those of certain toxicants.

The relationship between the oxidative stress reaction and the microbial community by a combinative method of PA and CCA

Earthworms, as the first choice for soil monitoring and bio-remediation of cadmium (Cd)-contaminated soil, need to identify its mechanism under Cd stress. In this study, an artificial soil test method was used to determine the oxidative stress reaction indices, amino acid composition, and microbial community changes in earthworms under different stress durations and concentrations. For the first time, the canonical correlation analysis model and path analysis model were innovatively introduced into the data analysis to determine the mechanism that drives earthworm physiological functions after Cd stress. The results showed that in the low-stress concentration treatments (50–125 mg.kg−1 DW), there was a driving relationship between oxidative stress reaction and microbial community in earthworm, and the driving factor was glycyl-L-glutamic acid at 50 mg.kg−1 DW. With the increase of Cd stress intensity, the enzymes of oxidative stress promoted the survival microbes to begin to proliferate, and SOD became the main driving factor under 125 mg.kg−1 DW Cd stress. In the high-stress concentration treatments (250–500 mg.kg−1 DW), the driving effects were weakened or disappeared; while Cd-resistant microbial population appeared. This study provides a theoretical basis for the driving mechanism between oxidative stress effect and microbial community after Cd stress.

Enantioselective toxicity and oxidative stress effects of acetochlor on earthworms (Eisenia fetida) by mediating the signaling pathway

Acetochlor (ACT) as a widely used chiral chloroacetamide herbicide is appropriate to evaluate the potential toxicity in soil ecosystems at enantiomeric level. The acute and subchronic toxicities of R-acetochlor (R-ACT) and S-acetochlor (S-ACT) on earthworms (Eisenia fetida) were investigated in the present study. Residual analyses showed that S-ACT degraded faster than R-ACT in artificial soil with half-lives of 16.5 and 21.7 d, respectively. Additionally, significant enantioselective acute toxicity in earthworms from between S-ACT and R-ACT (p < 0.05) was observed, and the acute toxicity of R-ACT were 1.9 and 1.5 times higher than those of S-ACT in the filter paper test and artificial soil test. The hydroxyl radical (OH−) content, superoxide dismutase (SOD) and antioxidant enzyme catalase (CAT) activities, and cytochrome P450 content in earthworms significantly increased under the influence of ACT enantiomers; however, the acetylcholinesterase (AchE) activity was significantly inhibited after exposure to the two enantiomers. Moreover, lipid peroxidation and DNA damage were induced by ACT enantiomers. The results of transcriptome sequencing indicated that R-ACT induced a stronger oxidative stress effect than S-ACT in earthworms by mediating signaling pathways, which may be the primary reason for the enantioselective toxicity between S-ACT and R-ACT. Overall, the results demonstrated that R-ACT has a higher risk than S-ACT in the soil environment, which is important for understanding the enantioselective behavior of chloroacetamide pesticides.

Tu1113 A BENCHTOP EVALUATION OF VARIOUS SUSPECTED BIOFILM RESERVOIRS WITHIN A DUODENOSCOPE

Multidrug resistant organisms (MDRO) / carbapenem resistant enterobacteriaceae (CRE) have emerged as serious public health problems, particularly among immune compromised patients. It is now known that duodenoscopes may transmit MDRO due to biofilm buildup, which may explain prior CRE outbreaks with culture-negative duodenoscopes. However, the precise location of biofilm buildup has been the subject of speculation. Thus, we aimed to investigate various suspected biofilm reservoir locations & scenarios among key, hard-to-reach components of a duodenoscope. This was a cross sectional translational study. Two key duodenoscope components were investigated – accessory channel tubing in various states of distress, & elevator wire conduit (known as a sus pipe). These two components were chosen either because they can be damaged in routine clinical use (accessory channel tubing), or because of a recent design change where the channel is sealed with O-rings (sus pipe), which prevents high-level disinfection (HLD) of the channel. Additionally, both areas are known to be difficult / impossible to brush, especially the sus pipe. New accessory channel tubing was cut into 2-inch segments, & cultured immediately (negative control), after biofilm creation (positive control), or after distressing the tubing in various manners & undergoing suboptimal HLD without manual brushing. New sus pipe was also cut into 2-inch segments & underwent negative control, positive control, & suboptimal HLD without manual brushing. To distress the tubing, we employed 3 techniques to simulate one year’s worth of “worst case scenario” duodenoscope usage – intentional abrasion (by passing a half-bowed sphincterotome or a cleaning brush through the tubing 1,872 times), or intentional tubing puncture with a commonly used injection needle. Thereafter, we created biofilm by mixing artificial test soil ATS 2015 with organisms that favor biofilm formation (E fecalis, P aeruginosa, & K pneumoniae), & enriched with defibrinated sheep blood. Each test segment was incubated for 5 days at 35°C, then rinsed with sterile water. Positive control segments underwent immediate sonication & culturing, while test segments underwent suboptimal HLD (a simulated HLD cycle without manual brushing), then sonicated & cultured. Culture x72h & Interpretation were performed in a blinded manner. Each of the testing arms was repeated in triplicate. The results are shown in table 1&2 (images) 1. Distressed tubing does not appear to promote biofilm formation even in a simulated “worst case scenario” of heavy usage, & suboptimal HLD

Combined effects of goethite nanoparticles with metallic contaminants and an organophosphorus pesticide on Eisenia andrei.

The effects of mixtures of nanoparticles (NPs) and other chemicals have been poorly studied in terrestrial invertebrates. In this study, we investigated the effects of binary mixtures of goethite (α-FeOOH) NPs and metallic (Cd and Pb) or organic (chlorpyrifos, CPF) contaminants in Eisenia andrei earthworms. We used the filter paper contact test to evaluate (i) the uptake of NPs in organisms exposed to the mixtures of NPs+Metals and NPs+CPF and (ii) the potential effects of the mixture of NPs+CPF on the CPF-induced inhibition of the biomarker enzymes acetylcholinesterase (AChE) and carboxylesterases (CES). We used the artificial soil test to deepen the study on joint effects of NPs+CPF. All compounds were applied separately and in binary mixtures. In the single exposure treatment, Fe levels decreased significantly in organisms exposed to NPs on filter paper, suggesting systemic effects aimed at eliminating Fe incorporated through NPs. Conversely, earthworms exposed to binary mixtures showed Fe levels similar (NPs+Metals) to or higher (NPs+CPF) than controls. The earthworms single exposed to NPs presented no changes in AChE and CES activities. In the artificial soil test, the only treatment that showed AChE inhibition after 72h was single CPF exposure, while no significant changes were observed in CES activity. However, after 7-day exposure in artificial soil or 72-h exposure on filter paper, the mixture of NPs+CPF induced a similar degree of AChE and CES inhibition as single CPF exposure. All these suggested that NPs did not produce neurotoxic effects, and that the inhibition of the enzymes' activities in all cases was due to the presence of the pesticide. On the other hand, the differences in the pattern of Fe accumulation in the earthworms indicate that the presence of other contaminants in the exposure media can modify the uptake and/or the excretion of Fe and evidence the interactions that may be found in binary mixtures of metal oxide NPs and other pre-existing contaminants in the soil ecosystem.

Effects of tetracycline on the relationship between the microbial community and oxidative stress in earthworms based on canonical correlation analysis

In this study, Eisenia fetida was taken as the test organism and tetracycline was taken as the stress compound. The artificial soil test was conducted to study the utilization intensity of different carbon sources (the Biolog-microplate supplied) by microorganisms under different stress times and stress concentrations. The changes in the in vivo key enzymes activities of earthworms and oxidative stress indicators, such as malondialdehyde (MDA), were explored. The canonical correlation analysis method was the first used to establish a analysis-model to explore the relationship between the functional diversity of microbial community and the oxidative stress in earthworms in vivo under different stress times and concentrations. Research shows: 1) after tetracycline stress, in the earthworm, the CAT, POD, SOD, GPX were related to the microbes that use carbohydrate carbon sources; the GST and AChE were related to the microbes that use polymer carbon sources; the MDA was related to the microbes that use carbon sources: amino acid, carboxylic acid and phenolic acid. 2) Under low concentrations of tetracycline stress, there was no significant relationship between the functional diversity of the microbial communities and the effects of oxidative stress at this concentration. The high concentration of tetracycline can be utilized to screen probiotics that alleviate the effects of oxidative stress. 3) The utilization of carbon sources by microbial community in the earthworm after stress can be used as biomarker of ecotoxicology. It provides a basic theoretical for adding beneficial carbon sources to combat oxidative damage in vivo.

The polytetrafluoroethylene (PTFE) channel model of cyclic-buildup biofilm and traditional biofilm: The impact of friction, and detergent on cleaning and subsequent high-level disinfection.

To evaluate the efficacy of detergent and friction on removal of traditional biofilm and cyclic-buildup biofilm (CBB) from polytetrafluoroethylene (PTFE) channels and to evaluate the efficacy of glutaraldehyde to kill residual bacteria after cleaning. PTFE channels were exposed to artificial test soil containing 108 CFU/mL of Pseudomonas aeruginosa and Enterococcus faecalis, followed by full cleaning and high-level disinfection (HLD) for five repeated rounds to establish CBB. For traditional biofilm, the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush, and Pull Thru channel cleaner were compared to a water flush only. Carbohydrate, protein, viable count, adenosine triphosphate (ATP) levels were analyzed and atomic force microscopy (AFM) was performed. In the absence of friction, cleaning of traditional biofilm and CBB was not effective compared to the positive control (Dunn-Bonferroni tests; P > .05) regardless of the detergent used. ATP, protein, and carbohydrate analyses were unable to detect traditional biofilm or CBB. The AFM analysis showed that fixation resulted in CBB being smoother and more compact than traditional biofilm. Friction during the cleaning process was a critical parameter regardless of the detergent used for removal of either traditional biofilm or CBB. Glutaraldehyde effectively killed the remaining microorganisms regardless of the cleaning method used.

Larvicidal and enzyme inhibition of essential oil from Spheranthus amaranthroids (Burm.) against lepidopteran pest Spodoptera litura (Fab.) and their impact on non-target earthworms

Abstract The present investigation was highlighted the green-derived Essential oils with bio-active derivatives of Sphaeranthus amaranthoides (Sa-EO) can be employed in larvicidal and enzyme inhibitory effects against threatening tobacco cutworm S. litura and their detrimental effects against soil indicator earthworms. Chemical screening of EO-Sa using GC-MS exposed thoroughly five major derivatives with major peak area in d -Carvone (89.7%). The larvicidal activity of both third and fourth instar were improved steadily with higher dosage of treatments (400, 600, 800 and 1000 ppm). The lethal concentration (LC50) for third and fourth instar larvae was observed at 2.71 and 2.74 ppm (log dosage) respectively. Correspondingly, the sub-lethal dosage of EO-Sa (500 ppm) reduced the enzyme activity of Acid Phosphatase (ACP), Alkaline Phosphatase (ALP) and Adenosine triphosphate (ATP) significantly in both third and fourth instars. Further, the gut-histological activity of EO-Sa (500 ppm) against fourth instar showed damaged and disintegrated epithelial cells (EL) and columnar cells (CC), gut lumen (GL) and brush border membrane (BBM). Finally, the non-target screening against E. euginae showed that the EO-Sa was found to be harmless even at the maximum dosage of 1000 and 1500 ppm as compared to synthetic chemical monocrotophos in both filter paper test (FPT) and artificial soil test (AST). Thus the present investigation evidenced that active phyto-chemistries of EO-Sa delivers a sturdy toxicological response against S. litura and harmless against non-target earthworm.

Mortality, growth and metabolic responses by 1H-NMR-based metabolomics of earthworms to sodium selenite exposure in soils

The rapid development of selenium-enriched agriculture leads to the accumulation of selenium in the soil, which has an adverse impact on terrestrial ecosystems. In the present study, the mortality, growth inhibition rate and metabolism of earthworms were examined to investigate the toxicological effects of sodium selenite (Na2SeO3) on earthworms (Eisenia fetida) after exposuring for 14 days (d). We used 1H-NMR-based metabolomics to identify sensitive biomarkers and explored the metabolic responses of earthworms exposed to Na2SeO3. The mortality and growth inhibition rate of earthworms exposed to 70 and 90 mg/kg Na2SeO3 were significantly higher than the rate of control group. The LC50 (the median lethal concentration) of Na2SeO3 was 57.4 mg/kg in this artificial soil test of E. fetida exposed to Na2SeO3 for 14 d. However, there was no significant differences when earthworms were exposed to different concentrations of Na2SeO3. The selected metabolic markers were ATP, lactic acid, leucine, alanine, valine, glycine, glutamic acid, lysine, α-glucose and betaine. Na2SeO3 affected the metabolic level of earthworms, as the percentage of metabolic markers in the earthworm changes when exposed to different concentrations of Na2SeO3. The metabolic disturbances were greater with increasing concentrations of Na2SeO3. The differential metabolic markers were significantly changed when exposed to Na2SeO3 comparing to those in the control group, affecting the tricarboxylic acid cycle process and breaking the metabolic balance. This study showed that Na2SeO3 had toxic effect on the growth and development of earthworms. In addition, this study provided a biochemical insights for the development of selenium-enriched agriculture.

Clinical Soil Removal from Flexible Endoscopes Is Critically Dependent on the Completeness of the Manual Cleaning Process

BACKGROUND Multiple outbreaks of carbapenem-resistant enterobacteriaceae (CRE) and other multi-drug resistant organisms (MDROs), have been associated with flexible endoscopes resulting in unacceptable patient mortality and morbidity. Evidence highlights the importance of effective cleaning to achieve effective high-level disinfection (HLD). The objective of this study is to quantify clinical soil removal from endoscopes through manual cleaning. METHODS This simulated-use study (85 individual trials) measured adenosine-triphosphate (ATP) and protein levels found in the suction/biopsy channel of OlympusTJF-160F duodenoscopes inoculated with an artificial test soil, after partial and complete manual cleaning. Three partial manual cleaning modes of critical importance were identified for the study: 1) incomplete brushing of the suction/biopsy channel, 2) omitting aspiration of the suction/biopsy channel, 3) cleaning an endoscope where soil dried for 24 hours. Analysis used one-way ANOVAs to determine statistical differences. p-values RESULTS Elevated ATP levels above the cleanliness criterion value of 200 relative light units (RLUs) (M.J. Alfa, et al.; AJIC; 41; (2013); 245-248 and 249-253; ANSI/AAMI ST91:2015) were detected for all the partial cleaning modes studied when compared to complete cleaning (p-value CONCLUSIONS This study highlights the importance of complete manual cleaning and finds that incomplete cleaning of duodenoscopes results in 6 to 14 times larger amounts of residual soil. Protein is not detected in partially cleaned duodenoscopes when ATP clearly indicates elevated amounts of remaining soil. The methodology and results of this study can be used to establish a better cleanliness criterion for monitoring the effectiveness of manual cleaning.

Oxidative stress and genotoxic effects in earthworms induced by five imidazolium bromide ionic liquids with different alkyl chains

In this study, the acute and subchronic toxicity of 1-alkyl-3-methyl imidazole bromide ionic liquids (ILs) [Cnmim]Br (n = 2, 4, 6, 10, 12) was evaluated utilizing earthworms (Eisenia fetida) as a basis for their impact on terrestrial ecosystems. The filter paper tests and artificial soil tests were conducted as acute toxicity tests to investigate the LC50 of ILs, while in subchronic toxicity tests, earthworms were exposed to ILs in artificial soil (5, 10, 20 and 40 mg kg-1) for 28 d. Reactive oxygen species (ROS), antioxidant enzymes, detoxifying enzymes and oxidative damage were measured to determine subchronic effects of ILs on E.fetida. The results showed that when the earthworms were exposed to these five ILs in acute toxicity experiments, [C2mim]Br had the lowest toxicity, as the alkyl length increased, the toxicity increased up to [C10mim]Br: a "cut-off effect" (decreased toxicity) was observed at [C12mim]Br. The results highlight the varying toxicity of ILs with different alkyl chains to E.fetida and provide valuable data for detailing the impact of ILs on ecological receptors.

Joint toxic effects of cadmium and four pesticides on the earthworm (Eisenia fetida)

The contaminants, instead of single contaminants, are usually found as chemical mixtures in terrestrial environment. However, little information is now available about the joint effects of heavy metals and farm chemicals on the soil organism. Our current study aimed to assess the combined toxicity of cadmium (Cd) and four pesticides (atrazine, chlorpyrifos, lambda-cyhalothrin and abamectin) to the earthworm (Eisenia fetida) with binary, ternary, quaternary and quinquenary mixtures. Two distinct kinds of bioassay systems were applied in this study, including contact filter paper test and artificial soil test. Synergistic effects were observed from two quaternary mixtures (Cd-Atrazine-Chlorpyrifos-Lambda-cyhalothrin and Cd-Chlorpyrifos-Lambda-cyhalothrin-Abamectin) and one quinquenary mixture (Cd-Atrazine-Chlorpyrifos-Lambda-cyhalothrin-Abamectin) in both bioassay systems. Besides, two binary mixtures (Cd-Atrazine and Cd-Lambda-cyhalothrin) and three ternary mixtures (Cd-Atrazine-Chlorpyrifos, Cd-Atrazine-Lambda-cyhalothrin and Cd-Chlorpyrifos-Lambda-cyhalothrin) also exhibited synergistic effects on E. fetida by the soil toxicity test. It is more practical to evaluate the contaminant toxicities to earthworm by soil toxicity test. Therefore, the effects of chemical mixtures on soil invertebrates might be underestimated by data obtained from single toxicant. Our findings would offer a better understanding of the complex effects of chemical mixtures on non-target living creatures, and these findings provided valuable insights into the interplay of different chemicals in natural environment.

Toxic effects of new ethyl-carbamates on the morphology, mortality and acetylcholinesterase activity of Eisenia foetida

The toxicity of the ixodicidal carbamates ethyl-4-bromophenyl carbamate (LQM 919), ethyl-4-chlorophenyl carbamate (LQM 996) and propoxur on Eisenia foetida adults was evaluated to estimate their ecotoxic potential. The earthworm mortality and weight loss produced by the three evaluated carbamates showed a concentration-dependent effect (p < 0.0001) in the contact filter paper test (CFPT). In the artificial soil test (AST), mortality increased in relation to the exposure time (p < 0.0001) and the concentration (p < 0.01) of the carbamates. Only the earthworms exposed in the CFPT showed morphological alterations. According to the LC50 obtained in the CFPT, the three carbamates were classified as very toxic and, according to the LC50 obtained in the AST, the three carbamates were classified as highly toxic for E. foetida. The values of ki and kd indicated that LQM 919 and LQM 996 are weak inhibitors with lower affinity for the acetylcholinesterase of E. foetida than that of propoxur. The concentrations in the CFPT and AST at which 100% mortality was observed in E. foetida were 64- and 4-fold higher, respectively, than the egg hatching inhibitory concentration 99% reported for ticks.