Adenosine Triphosphate Values Research Articles

A comparison of adenosine triphosphate with other metrics of microbial biomass in a gradient from the North Atlantic to the Chesapeake Bay

A new, simplified protocol for determining particulate adenosine triphosphate (ATP) levels allows for the assessment of microbial biomass distribution in aquatic systems at a high temporal and spatial resolution. A comparison of ATP data with related variables, such as particulate carbon, nitrogen, chlorophyll, and turbidity in pelagic samples, yielded significant and strong correlations in a gradient from the tributaries of the Chesapeake Bay (sigma-t = 8) to the open North Atlantic (sigma-t = 29). Correlations varied between ATP and biomass depending on the microscopic method employed. Despite the much greater effort involved, biomass determined by microscopy correlated poorly with other indicator variables including carbon, nitrogen, and chlorophyll. The ATP values presented here fit well within the range of ATP biomass estimates in the literature for similar environments. A compilation of prior research data from a wide range of marine habitats demonstrated that ATP values can be ranked according to broad trophic gradients, from the deep sea to eutrophic inland waters. Using a mass-based conversion factor of 250, the contribution of biomass to overall particulate organic carbon (POC) ranged from 15% to 30% along the gradient, from the open ocean to locations in the Chesapeake Bay respectively. Our data corroborate the notion that ATP, due to its consistency and simplicity, is a promising high-throughput indicator of cytoplasm volume with distinct benefits over cell counts and measures of chlorophyll or POC.

Can the adenosine triphosphate (ATP) bioluminescence assay be used as an indicator for hospital cleaning? - A pilot study.

In hospital cleaning, there is currently no standard for uniform monitoring of surface cleaning, either in Germany or internationally. One possibility for monitoring is the use of so-called objective methods for checking cleaning performance (e.g. fluorescence or adenosine triphosphate (ATP) method). The aim of the study was to monitor and evaluate the implementation of the adenosine triphosphate (ATP) bioluminescence assay as a cleaning indicator in everyday hospital cleaning, in order to verify its utility and effectiveness. In three phases, five frequently touched surfaces were examined with the ATP bioluminescence assay at different time points. 846 measurements were performed on the dermatology ward of a university hospital (phase 1), 1,350 measurements were performed on five different wards of the university hospital (phase 2), and 1,044 measurements were performed on five wards of another large hospital (phase 3). For this purpose, one structurally old and one structurally new ward as well as an intensive care unit (ICU), an outpatient clinic and a radiology department were selected for phases 2 and 3. With the ATP bioluminescence method, we were able to demonstrate a reduction in values after cleaning: before cleaning mean of ATP, 907 relative light units (RLU) (95% confidence interval [CI] 777; 1,038); after cleaning mean=286 RLU (CI=233; 495) (phase 1) and by intervention (five hours after daily cleaning mean=360 RLU (CI=303; 428); five hours after daily cleaning and two additional cleanings mean=128 RLU (CI=107; 152) (phase 3). The ATP values increased five hours after cleaning in phases 1 and 2, and eight hours after cleaning in phase 3. The structurally old wards had the highest ATP content, the ICU and the radiology department, among others, the lowest. In all phases, door handles showed both a reduction after cleaning or intervention and a subsequent increase in ATP values. Chair armrests, examination tables and door handles had high ATP values overall. The study shows ward differences both for cleaning effects and for the soiling characteristics of surfaces during the course of the day. In addition, it demonstrates the benefit of intermediate cleaning twice a day. It is noteworthy that structurally old stations and older inventory were more heavily soiled and, in some cases, more difficult to clean. The results show that the ATP bioluminescence method is suitable for detecting cleaning effects and can be used in everyday clinical practice for simple cleaning monitoring. Furthermore, it enables the detection of risk surfaces and easy-to-clean surfaces with significant re-soiling.

Assessment of endoscope reprocessing at World Gastroenterology Organisation training centers using adenosine triphosphate testing.

Background and study aims Adequacy of endoscope disinfection in resource-limited settings is unknown. Adenosine triphosphate (ATP) testing is useful for evaluation of endoscope reprocessing, and ATP <200 relative light units (RLUs) after manual endoscope cleaning has been associated with adequacy of endoscope disinfection. Methods Consecutive endoscopes undergoing reprocessing at five World Gastroenterology Organisation (WGO) training centers underwent ATP testing before and after an on-site educational intervention designed to optimize reprocessing practices. Results A total of 343 reprocessing cycles of 65 endoscopes were studied. Mean endoscope age was 5.3 years (range 1-13 years). Educational interventions, based on direct observation of endoscope reprocessing practices at each site, included refinements in pre-cleaning, manual cleaning, high-level disinfection, and endoscope drying and storage. The percentage of reprocessing cycles with post-manual cleaning ATP ≧200 decreased from 21.4% prior to educational intervention to 14.8% post-intervention ( P =0.11). In multivariable logistic modelling, gastroscopes were significantly less likely (odds ratio [OR] 0.04, 95% confidence interval [CI] 0.01-0.19; P <0.001) than colonoscopes to achieve post-manual cleaning ATP < 200. No other factor (educational intervention, study site, endoscope age) was significantly associated with improved outcomes. Endoscope ID was not significantly associated with ATP values, and sites that performed manual versus automated HLD did not have significantly different likelihood of post-manual cleaning ATP <200 (OR 1.18, 95% CI 0.56-2.50; P =0.67). Conclusions In resource-limited settings, approximately 20% of endoscope reprocessing cycles may result in inadequate disinfection. This was not significantly improved by a comprehensive educational intervention. Alternative approaches to endoscope reprocessing are needed.

Effect of nitric oxide delivery on energy supply of renal tissue in cardiopulmonary bypass: an experimental study

Introduction. Acute kidney injury is a common complication of cardiac surgery with cardiopulmonary bypass. Ischemic-reperfusion injury, systemic inflammation, oxidative stress, and other factors that occur during cardiopulmonary bypass lead to disruption of energy supply and death of kidney tissue cells. Delivery of nitric oxide is a promising method of nephroprotection during cardiosurgical operations with cardiopulmonary bypass.Aim: To study the parameters of energy supply of the renal tissue during cardiopulmonary bypass with nitric oxide delivery in the experiment.Material and Methods. A prospective controlled experimental study was performed on 12 rams. Animals were included in 2 equal groups at a ratio of 1:1. In the main group, nitric oxide was delivered at a dose of 80 ppm immediately after tracheal intubation and within 90 minutes of cardiopulmonary bypass (main group, n = 6). In the control group, mechanical ventilation and cardiopulmonary bypass were performed according to standard protocols (control group, n = 6). Biopsy specimens of kidney tissue were taken 1 hour after weaning from cardiopulmonary bypass. Energy supply was assessed (according to the tissue concentration of adenosine triphosphate (ATP) and lactate).Results. Delivery of nitric oxide was not accompanied by tissue perfusion aberration during cardiopulmonary bypass (CPB). The level of free hemoglobin in both groups was statistically significantly higher 1 hour after cardiopulmonary bypass compared with the stages of intubation – p &lt; 0.000... and the beginning of CPB – p &lt; 0.000... The ATP value significantly differed between groups and amounted in the control group 3.7 ± 0.62 nmol/g; in the main group 6.8 ± 1.11 nmol/g, р = 0.00011. The lactate concentration did not differ statistically significantly between the groups and amounted to: in the control group 12.9 ± 3.71 nmol/g; in the main group 10.2 ± 2.14 nmol/g, р = 0.1502.Conclusion: Delivery of nitric oxide improved the parameters of energy supply of the renal tissue during cardiopulmonary bypass in the experiment.

Apparent diffusion coefficients of 31P metabolites in the human calf muscle at 7 T

PurposeIn this study, we aimed to measure the apparent diffusion coefficients (ADCs) of major phosphorous metabolites in the human calf muscle at 7 T with a diffusion-weighted (DW)-STEAM sequence.MethodsA DW-STEAM sequence with bipolar gradients was implemented at 7 T, and DW MR spectra were acquired in three orthogonal directions in the human calf muscle of six healthy volunteers (TE/TM/TR = 15 ms/750 ms/5 s) at three b-values (0, 800, and 1200 s/mm2). Frequency and phase alignments were applied prior to spectral averaging. Averaged DW MR spectra were analyzed with LCModel, and ADCs of 31P metabolites were estimated.ResultsFour metabolites (phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi) and glycerol phosphorylcholine (GPC)) were quantified at all b-values with mean CRLBs below 10%. The ADC values of PCr, ATP, Pi, and GPC were (0.24 ± 0.02, 0.15 ± 0.04, 0.43 ± 0.14, 0.40 ± 0.09) × 10–3 mm2/s, respectively.ConclusionThe ADCs of four 31P metabolites were successfully measured in the human calf muscle at 7 T, among which those of ATP, Pi and GPC were reported for the first time in humans. This study paves the way to investigate 31P metabolite diffusion properties in health and disease on the clinical MR scanner.

SG-APSIC1024: The importance of the washing evaluation of flusher disinfector in the medical site: Visual evaluation with the ISO standardized test soil and adenosine triphosphate level

Objectives: We examined the washing evaluation method of the flusher disinfector installed in the medical site by visual evaluation using an ISO test soil and adenosine triphosphate (ATP) measurement. Methods: The test soil shown in ISO15883-5 was applied to the bedpan using 2 methods (N = 10) and was then visually evaluated using a 4-step scale. The ATP value on the surface of the bedpan corresponding to each scale was measured, and the correlation with the visual scale was confirmed. In addition, a visual evaluation was performed using a different flusher disinfector and bedpan (N = 3). Results: In the visual evaluation, when the test soil was applied to the entire surface of the bedpan, it remained in the parts where the water flow was hard to hit. When the test soil was applied to the surface of the bedpan except the lid, no soil remained. The 4-step visual evaluation scale and the logarithm of ATP value showed a positive correlation. In visual evaluations with different flusher disinfector and bedpan combinations, the residual soil patterns tended to be different. Some bedpans showed washing failure related to improper design. Conclusions: Poor cleaning of flusher disinfectors may occur when the amount of water used is insufficient or when the bedpan is significantly contaminated. It is important to carry out flusher disinfector washing evaluation at medical sites to evaluate the function of flusher disinfectors. An appropriate program must be utilized for staff education and appropriate management. Because flusher disinfectors and bedpans differ, flusher disinfector cleaning evaluations should be carried out at all facilities.

Impact of Plastic-Wrap Properties and Cleaning Intervals on the Disinfection of Elevator Buttons.

Fomite transmission is a possible route by which different pathogens spread within facilities. In hospital settings, elevator buttons are widely observed to be covered with various types of plastic wraps; however, limited information is available concerning the impact of different plastic materials on cleaning. Our study aimed to identify which plastic material is suitable for the coverage of elevator buttons and the optimal intervals for their cleaning. We tested six plastic covers, including polyethylene (PE), polymethylpentene (PMP), polyvinyl chloride (PVD), and polyvinylidene chloride (PVDC) plastic wraps; a thermoplastic polyurethane (TPU) keyboard cover; and a polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) laminating film, which are plastic films. The bioburden on the elevator buttons at different time intervals was measured using an adenosine triphosphate (ATP) bioluminescence assay. Our results show that wraps made of PVDC had superior durability compared with those of PMP, PVC, and PVDC, in addition to the lowest detectable ATP levels among the six tested materials. Regarding different button locations, the highest ATP values were found in door-close buttons followed by door-open, and first-floor buttons after one- and three-hour intervals (p = 0.024 and p < 0.001, respectively). After routine disinfection, the ATP levels of buttons rapidly increased after touching and became more prominent after three hours (p < 0.05). Our results indicate that PVDC plastic wraps have adequate durability and the lowest residual bioburden when applied as covers for elevator buttons. Door-close and -open buttons were the most frequently touched sites, requiring more accurate and precise disinfection; therefore, cleaning intervals of no longer than three hours may be warranted.

Monitoring of surface cleaning and disinfection in a Brazilian pediatric unit.

Understanding the correlation between the methods of monitoring surface cleaning and disinfection (SCD) is fundamental for better infection control. This study aims to correlate the SCD monitoring methods in a Brazilian pediatric unit. This is an exploratory, longitudinal, and correlational study. The study was conducted in a pediatric hospitalization unit of a medium-sized hospital from December 2020 to March 2021. Four high-contact surfaces were analyzed before and after the cleaning and disinfection process by means of visual inspection, quantification of adenosine triphosphate (ATP), and colony-forming unit (CFU) count. The study consisted of three stages: stage I involving situational diagnosis of the SCD process; stage II referring to the implementation of the Surface Cleaning and Disinfection Standardization Program (SCDSP); and stage III involving long-term assessment after implementing the program. A total of 192 assessments were performed in each stage, totaling 576 in the three study stages. A significant correlation was found between the ATP quantification methods and microbial count in the bed railing (p = 0.009) and companion's armchair (p = 0.018) surfaces. In both cases, Spearman's correlation coefficients were positive, indicating a positive correlation between ATP and microbial count scores, that is, the higher the ATP values (in RLUs), the greater the microbial counts (in CFUs/cm2). The analysis of the ROC curves suggests that the surfaces presenting ATP below 108 RLUs can be considered approved. The ATP method yielded 78.6% sensitivity; in turn, microbial count presented a sensitivity of 85.7%. It is important to use different methods to monitor the cleaning and disinfection of surfaces, as each one has different sensitivity and specificity.

Simple neutralization test report: Do probiotics contribute to COVID-19 therapy?

BackgroundThere is an urgent need to identify effective therapy to treat coronavirus diseases 2019 (COVID-19). Supplement consumption is becoming popular in this pandemic era. An example of this is probiotic consumption to improve the host's immune system. ObjectiveThis study aimed to prove whether antibodies from people taking probiotics could influence lactate dehydrogenase (LDH), adenosine triphosphate (ATP) values, and cell viability in vitro in peripheral blood mononuclear cells (PBMCs) inoculated with the SARS-CoV-2 spike protein as COVID-19 cells models. MethodsThis was an experimental study with control and intervention groups, totally in 12 groups divided based on antibody levels, probiotic intervention, probiotic non-intervention group, SARS-CoV-2 infection group, and non-SARS-CoV-2 infection group. In vitro assays were carried out on PBMC cell cultures inoculated with S1 SARS-CoV-2 recombinant as a COVID-19 cell model. The COVID-19 cell model was given antibodies divided into three antibody level groups: sRBD levels of <3, 325.76 and 646.18. The cytotoxicity assessment examined increased levels of LDH, cytopathic activity by measuring ATP levels, and cell viability by XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay. Data were analyzed with SPSS 21 for Windows. ResultsThis study showed a significant difference in the LDH value (p < 0.001) between each group. The difference in ATP values between groups was significant (p < 0.001). Meanwhile, the cell viability examination found that there was a tendency of decreased XTT (cell viability in %) when there was an increase of LDH and ATP. ConclusionThe change of LDH values occurred most in the antibody group that did not consume probiotics. The highest cytopathic activity based on the ATP values occurred in the infected cell culture group with antibody levels of 325.76 and consuming probiotics. In addition, LDH and ATP activities provided evidence of a significant influence on cell viability.

Bacteria Wear ICG Clothes for Rapid Detection of Intracranial Infection in Patients After Neurosurgery and Photothermal Antibacterial Therapy Against Streptococcus Mutans.

Bacterial infection is one of the most serious physiological conditions threatening human health. There is an increasing demand for more effective bacterial diagnosis and treatment through non-invasive approaches. Among current antibacterial strategies of non-invasive approaches, photothermal antibacterial therapy (PTAT) has pronounced advantages with properties of minor damage to normal tissue and little chance to trigger antimicrobial resistance. Therefore, we developed a fast and simple strategy that integrated the sensitive detection and photothermal therapy of bacteria by measuring adenosine triphosphate (ATP) bioluminescence following targeted photothermal lysis. First, 3-azido-d-alanine (d-AzAla) is selectively integrated into the cell walls of bacteria, photosensitizer dibenzocyclooctyne, and double sulfonic acid-modified indocyanine green (sulfo-DBCO-ICG) are subsequently designed to react with the modified bacteria through in vivo click chemistry. Next, the sulfo-DBCO-ICG modified bacteria under irradiation of 808 nm near-infrared laser was immediately detected by ATP bioluminescence following targeted photothermal lysis and even the number of bacteria on the infected tissue can be significantly reduced through PTAT. This method has demonstrated the ability to detect the presence of the bacteria for ATP value in 32 clinical samples. As a result, the ATP value over of 100 confirmed the presence of bacteria in clinical samples for 22 patients undergoing craniotomy and ten otitis media patients. Overall, this study paves a brand new avenue to facile diagnosis and a treatment platform for clinical bacterial infections.

The value of adenosine triphosphate in CD4(+)T lymphocytes in predicting repeated respiratory tract infections in silicosis patients

Objective: To explore the value of the concentration of adenosine triphosphate (ATP) in CD4(+)T lymphocytes in predicting repeated respiratory tract infections (RRTI) in silicosis patients. Methods: In April 2020, 614 silicosis patients admitted from March 2016 to March 2018 were included in the study, and they were divided into the RRTI group (n=105) and the non RRTI group (n=509) according to whether the occurrence of RRTI, another 30 healthy cases taken from body check were served as control group, and the concentrations of ATP produced by CD4(+)T lymphocytes was measured by ImmuKnow assay, and were compared between the three groups. And drawed the receiver operating characteristic (ROC) curve, and the Logistic regression analysis was used to explore the risk factors of RRTI. Results: The incidence of RRTI in silicosis patients was 17.10% (105/614) . The concentration of ATP produced by CD4(+)T lymphocytes in the RRTI group [ (260.42±90.36) mg/L] was significantly lower than that in the non RRTI group [ (413.66±138.74) mg/L] (t=-10.849, P<0.01) . The area under the ROC curve was 0.834, the cutoff value was 284 mg/L, the sensitivity was 0.88, and the specificity was 0.83. Logistic regression analysis showed that the concentration of ATP produced by CD4(+)T lymphocytes≤284 mg/L, impaired pulmonary ventilation function, serum albumin<40 g/L and diabetes were the risk factors of RRTI in silicosis patients (OR=2.126, 1.217, 1.164, 1.125, P<0.05) . Conclusion: Low CD4(+)T lymphocyte ATP value was a risk factor of RRTI in silicosis patients, and can predict the risk of RRTI in patients with silicosis.

Two novel protocols for cleaning residual simethicone and fluid in patient‐ready duodenoscopes

Approximately 42-95% of working channels have been reported to show the presence of residual fluid despite endoscope reprocessing. The aim of this study was to design two novel protocols for cleaning residual simethicone and demonstrate its efficiency by evaluating the residual fluid and cleanliness in the working channels of patient-ready duodenoscopes. The designed protocol for cleaning residual simethicone was implemented in manual cleaning and/or high-level disinfection (HLD). The residual fluid inside the working channels was estimated by visual inspection. Adenosine triphosphate (ATP) values were evaluated to determine cleanliness after manual cleaning. Manual cleaning with novel simethicone cleaning protocol demonstrated a significant decrease in fluid droplets (14.6±29.9 vs 0±0, P<0.001) and ATP values (157±196 relative light units [RLUs] vs 52±41 RLUs, P=0.031). HLD with simethicone cleaning protocol, using either enzymatic detergent with effective for cleaning simethicone or cleaning time set in the automatic endoscope reprocessor program for 8min, demonstrated significant decrease in the number of fluid droplets. Follow-up after the implementation of the simethicone cleaning protocol showed a significant decrease in fluid droplets (37.4±41.0 vs 2.1±5.5, P=0.003) and ATP values (271±268 RLUs vs 82±136 RLUs, P=0.021). Simethicone cleaning protocol is advantageous for significantly decreasing fluid droplets and ATP values within endoscope working channels. After manual cleaning with the simethicone cleaning protocol, in particular, no retained fluid droplet was observed in patient-ready duodenoscopes.

Activation of the ATP-P2X pathway by TRPV4 in acute ocular hypertension

To measure the expression of transient receptor potential cation channel subfamily V member 4 (TRPV4) in the rat cornea and determine whether it is related to adenosine triphosphate (ATP) generation in a rat model of acute ocular hypertension (AOH). Immunofluorescence staining of TRPV4, P2X2 receptor, P2X3 receptor, and β3-tubulin in rat corneal longitudinal sections and paved was performed to clearly display histological structures. Rat models of AOH and agonist/antagonist-treated groups were established and corneal ATP was measured using an ATP assay. The independent t-test and simple linear correlation model were adopted for statistical analyses. Immunofluorescence staining of rat cornea sections revealed that epithelial and endothelial membranes showed strong immunoreactivity for TRPV4 and P2X2 receptor and coexpression with β3-tubulin in the rat corneal epithelial layer. Corneal ATP was significantly higher in the AOH rat model than in the control (P<0.05) and apparently lower after pretreatment by applying eyedrops of TRPV4 antagonist RN1734 with 30-40 mm Hg intraocular pressure (IOP; P<0.05). A simple linear regression model showed a positive correlation between rat corneal ATP and IOP values (R 2=0.996, P=0.0134) from the normal IOP (113 mm Hg) to 40 mm Hg. At 10-40min after anterior chamber injection of GSK1016790A (0.01 mL, 50 nmol/L in 0.9% NaCl), corneal ATP was significantly higher than in the control group (P<0.05), which peaked at 10min. The ATP concentration of the normal epithelium was higher than that of the endothelium in the AOH rat model and after anterior chamber injection of GSK1016790A (P<0.05). The ATP concentration in the AOH rat cornea is increased by TRPV4 activation.

Bioluminescence-based hygiene evaluation of public washroom environment: Repeated measurement of posthandwashing facilities on baseline and before and after cleaning schedule

The risk of hand recontamination is often neglected after using hand washing facilities, which can increase the spread of pathogens. The study aimed to evaluate the hygienic condition of posthandwashing facilities in public washrooms at different timeslots, particularly those near food courts and restaurants located in shopping malls. This observational study was conducted in 12 public washrooms that ranged from low-end, middle-end, to high-end category on 3 different timeslots including baseline, T1 (immediate postcleaning) and T2 (1-hour postcleaning, with counting the footfall). Hand-touch surfaces with a high risk of recontamination after handwashing, which included paper tower dispensers, air drying outlets, and exit door handles, were evaluated by the surface adenosine triphosphate (ATP) bioluminescence method (ATP-value). ATP-values <500 relative light units (RLUs) were considered a good hygiene. Cleaning schedules and footfalls of each sampled washroom were obtained by direct observations. The overall mean ATP value of washroom was 785 RLU (N = 108); the ATP values of female and male washrooms at T2 were 203 and 3,718 RLUs, respectively. The highest ATP value was found on the exit door handles of male washrooms (range = 13-26,695 RLUs, mean = 3,229 RLU). Regarding passed/failed hygiene conditions, there were significant differences in the proportion of exit door handles between genders (P = .018) and timeslots (P = .007) as well as that of paper towel button/screw between timeslots (P= .025). Attention should be paid at the exit door handles of male washrooms, where are high risks of cross and re-contamination.

Evaluating adenosine triphosphate bioluminescence for biomonitoring in potable water systems

Abstract The application of adenosine triphosphate (ATP) bioluminescence technology as a rapid microbiological activity monitor within a potable water system has been demonstrated. ATP measurements were taken pre- and post-infrastructure improvements within a watershed and throughout two potable water systems from source to tap. A reduction in ATP, as measured by relative light units, was identified post-infrastructure improvements. Peak ATP values for the watershed were found within the reservoirs. The treated source water remained biologically stable throughout the distribution system, with peaks attributed to nitrification. A mathematical model for predicting microbial ATP using pH, temperature, and alkalinity, was developed for the watershed studied, with an adjusted R2 of 0.84 at a 95% confidence level. Overall, ATP bioluminescence technology was found to be a suitable candidate for rapid microbiological activity testing in drinking water systems; however, technological limitations remain with respect to reproducibility that should be addressed prior to full-scale implementation.

Evaluation of adenosine triphosphate testing for on-farm cleanliness monitoring compared to microbiological testing in an empty pig farrowing unit.

Careful cleaning and disinfection of pigpens is essential to prevent disease spread and avoid the resultant economic losses. Hygiene in pigpens is generally evaluated by visual monitoring supplemented with bacteriological monitoring, which includes counting the total aerobic bacteria (TAB) and/or fecal indicator bacteria (FIB). However, these methods present drawbacks such as time and labor requirements. As adenosine triphosphate (ATP) is ubiquitous in all living organisms including microorganisms, this study aimed to directly compare the results of microbial assessment and ATP quantification, and to suggest possible detailed application methods of the ATP test for hygiene evaluation in pigpens of a farrowing unit. Before and after standard cleaning procedures, samples were collected from the floor corner, floor center, and feeding trough of four pigpens at different time points. No FIB were detected and both the TAB and ATP levels were significantly decreased in the floor center area after cleaning. FIB were continuously detected after cleaning and disinfection of the floor corners, and there was no significant ATP level reduction. The feeding trough did not show any significant difference in these values before and after cleaning, indicating insufficient cleaning of this area. The levels of TAB and ATP after cleaning were significantly correlated and the average ATP value was significantly lower in the absence of FIB than in their presence. In the absence of standard references, a more thorough hygiene management could be achieved evenly by supplementing cleaning or disinfection based on the lowest ATP results obtained at the cleanest test site, which in the present study was the floor center. Overall, these results indicate that the on-farm ATP test can be used to determine the cleanliness status, in addition to visual inspection, as an alternative to laboratory culture-based testing for the presence of microorganisms.

Surface distribution of severe acute respiratory syndrome coronavirus 2 in Leishenshan Hospital in China

The global pandemic of Corona Virus Disease 2019 (COVID-19) necessitated the rapid construction of field hospitals as the main strategies to control the detrimental effects of the outbreak. Little is known about the extent of the environmental contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in an urgently field hospital. A total of 66 surface samples were randomly collected from a general isolation ward and an ICU (intensive care unit) at a rapidly built field hospital (Wuhan Leishenshan Hospital) in Wuhan, China, from 12 March to 17 March 2020. The samples were used for SARS-CoV-2 detection and ATP (adenosine triphosphate) monitoring. Among these samples, 3.03% tested positive for SARS-CoV-2. The nurses' hands and nurse station in the ICU were weakly positive (CT value = 38.79; CT value = 37.56) and the ATP value of these two sites was higher than the mean value of all samples (ATP = 817; ATP = 577). The environmental cleaning and disinfection normalization bundle measures in Leishenshan hospital included air disinfection, object surface cleaning and disinfection, instrument equipment surface disinfection and hand hygiene, etc. These have been tested and were shown to be reliable and useful. Our experience can provide a useful reference in the fight against the ongoing pandemic of COVID-19.

Biofouling control by phosphorus limitation strongly depends on the assimilable organic carbon concentration

Nutrient limitation is a biofouling control strategy in reverse osmosis (RO) membrane systems. In seawater, the assimilable organic carbon content available for bacterial growth ranges from about 50 to 400 μg C·L−1, while the phosphorus concentration ranges from 3 to 11 μg P·L−1. Several studies monitored biofouling development, limiting either carbon or phosphorus. The effect of carbon to phosphorus ratio and the restriction of both nutrients on membrane system performance have not yet been investigated.This study examines the impact of reduced phosphorus concentration (from 25 μg P·L−1 and 3 μg P·L−1, to a low concentration of ≤0.3 μg P·L−1), combined with two different carbon concentrations (250 C L−1 and 30 μg C·L−1), on biofilm development in an RO system. Feed channel pressure drop was measured to determine the effect of the developed biofilm on system performance. The morphology of the accumulated biomass for both carbon concentrations was characterized by optical coherence tomography (OCT) and the biomass amount and composition was quantified by measuring total organic carbon (TOC), adenosine triphosphate (ATP), total cell counts (TCC), and extracellular polymeric substances (EPS) concentration for the developed biofilms under phosphorus restricted (P-restricted) and dosed (P-dosed) conditions.For both carbon concentrations, P-restricted conditions (≤0.3 μg P·L−1) limited bacterial growth (lower values of ATP, TCC). A faster pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 250 μg C·L−1 was dosed. This faster pressure drop increase can be explained by a higher area covered by biofilm in the flow channel and a higher amount of produced EPS. Conversely, a slower pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 30 μg C·L−1 was dosed. Results of this study demonstrate that P-limitation delayed biofilm formation effectively when combined with low assimilable organic carbon concentration and thereby, lengthening the overall membrane system performance.

1166 A NEW DESIGNED DUODENOSCOPE WITH DETACHABLE DISTAL CAP CAN SIGNIFICANTLY REDUCE ORGANIC RESIDUE CONTAMINATION AFTER REPROCESSING EVALUATED BY ADENOSINE TRIPHOSPHATE TEST

Because of its complex structures with an elevator mechanism, cleaning and disinfection of the duodenoscope are more difficult than other endoscopes. Despite high level disinfection (HLD) protocol, several outbreaks of multidrug resistance bacterial contamination (BC) of the duodenoscope with fixed distal cap were reported. A new designed duodenoscope with detachable distal cap (ED 580XT, Fujifilm, Tokyo, Japan) may have advantage over the conventional duodenoscope with fixed distal cap by allowing the brush to access the backside of the elevator. However, comparative data on BC and organic residue of the conventional duodenoscope vs. the duodenoscope with detachable distal cap after HLD is lacking. During December 2018-April 2019, 108 used duodenoscopes with detachable distal cap underwent HLD and were enrolled 1:1 into group A and group B. In group A (n=54), the distal cap of duodenoscope was detached before manual cleaning (figure 1A and 1B). Whereas in group B (n=54), the distal cap was not detached before manual cleaning (figure 1C and 1D) in order to imitate the conventional duodenoscope with fixed distal cap. After single round of HLD, sample was collected from the elevator site (ES) with swab rotation and submitted for culture and then rapid BC and organic residue evaluation were done by analyzing for Relative Light Units (RLU) that read by adenosine triphosphate (ATP) test (Clean-Trace Surface ATP, 3M, MN, USA). Based on our previous data that demonstrated 100% sensitivity and 100% negative predictive value for BC, the ATP threshold at 40 RLU was used in this study. We compared the proportion of potential BC and organic residue evaluated by rapid ATP test and confirmed BC evaluated by bacterial culture in group A vs. group B after HLD. After HLD, using the ATP threshold at 40 RLU as the cut-off value, the proportion of potential BC and organic residue in group A was significantly lower than that of in group B [20/54 (37%) vs. 41/54 (75.9%); p<0.001] (Table 1). Mean ATP value in group A was also significantly lower than that of in group B [45.2 RLU (range 9-209) vs. 151.9 RLU (range 19-653); p<0.001). In group B, one culture sample was found to have non-pathogenic BC (coagulase negative Staphylococcus). Pathogenic BC confirmed by culture was not documented in the both groups. Since a new design, detachable duodenoscope allows brushing the backside of elevator, it can reduce residual organic material confirmed by the ATP test. Although no pathological organism was found after HLD in both groups, BC from skin and membrane flora was still detected in duodenoscope with fixed distal cap.Table 1Comparison of ATP testing and culture results between the duodenoscope with detachable distal cap vs. the duodenoscope with fixed distal cap after HLDView Large Image Figure ViewerDownload Hi-res image Download (PPT)

A newly designed duodenoscope with detachable distal cap significantly reduces organic residue contamination after reprocessing.

A newly designed duodenoscope with detachable distal cap may reduce bacterial contamination by allowing better access to the elevator. We compared bacterial contamination and organic residue evaluated by rapid adenosine triphosphate (ATP) test and culture from duodenoscopes with detachable vs. fixed distal caps after high-level disinfection (HLD). During December 2018-April 2019, 108 used newly designed duodenoscopes were enrolled. In group A (n = 54), the distal cap of the duodenoscope was detached before manual cleaning. In group B (n = 54), the distal cap was not detached. After HLD, samples were collected from the elevator, submitted for culture, and evaluated using the ATP test, using the cutoff value of 40 relative light units (RLUs). After HLD, the proportion of potential bacterial contamination and organic residue in group A was significantly lower than in group B (37.0 % vs. 75.9 %; P < 0.001; relative risk 0.49, 95 % confidence interval 0.33-0.71), and also confirmed by median ATP values (45.2 vs. 141.0 RLU; P < 0.001). In group B, one sample culture was positive for nonpathogenic bacteria. Pathogenic bacteria were not found in any culture from either group. The detachable distal cap was more effective at eliminating bacterial contamination and reducing organic residue than a fixed cap. Nonpathogenic bacteria were detected in the fixed cap group after reprocessing. The ATP test with 40 RLU cutoff is a practical method to ensure the cleanliness of duodenoscope reprocessing without the need to wait for bacterial culture results.