A novel flotation technique for the separation of nonadherent micro-organisms from a substrate.

UNLABELLED: An understanding of adherence ability is crucial in many areas, for example, in research on biofilms, evaluation of probiotics or in biotechnology. In all these analyses, the reproducible washing is very important in the prevention of false results. During washing, the force, direction of the flow, position of the pipette tip, number of washing cycles, type of washing solution and the way of removing the washing solution can be sources of inappropriate stress to attached cells. To overcome these problems, we here propose the use of high mass density solutions as flotation agents. As the density of bacteria is lower than that of the flotation solutions, nonattached or weakly attached bacteria are moved to the surface due to hydrostatic force. Caesium chloride, ammonium nitrate and sodium diatrizoate solutions, which are commonly used as FAs, were compared with a standard method of rinsing. Several concentrations of agents were used to investigate the optimal concentration and influence of hydrostatic pressure on adhered micro-organisms. We show that flotation is a rapid method for distinguishing between adhered and weakly attached or loosed cells with reproducible results. Due to its range of possible mass density concentration, the best FA was shown to be caesium chloride. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that suggests using flotation agents to separate planktonic from adhered bacteria. When a high-density solution is used, buoyancy of bacteria ensures their segregation in the solution. Flotation agents could be used instead of washing procedure, which is inaccurate and hardly reproducible. High-density flotation agents could be used for more precise evaluation of bacterial adherence in many assays, such as research of biofilms or evaluation of probiotics.

The effect of prebiotics on adherence of probiotics.

Prebiotics are generally considered to promote the function or viability of probiotics via their fermentation, but their effect on the adherence of probiotics is still unclear. In this study, we examined the effect of 4 commercially available prebiotics [Orafti GR, Orafti P95, and Orafti Synergy (Beneo GmbH, Mannheim, Germany), and Vivinal (Friesland Foods Domo, Amersfoort, the Netherlands)] and 3 simple saccharides (glucose, galactose, and lactose) on the adherence of 5 probiotic type strains, 2 lactococci starter cultures, and 5 potential dairy probiotic strains from the Culture Collection of Dairy Microorganisms (Tábor, Czech Republic). Adherence was tested in microtiter plates on the following types of substrate: polystyrene alone and polystyrene coated with either porcine mucus or cocultures of the human colon cell lines Caco2 and HT29-MXT (1:9 ratio of HT29-MXT:Caco2). Adherence was evaluated as a change in fluorescence in the well of a microtiter plate. The most commonly observed effect (with a few exceptions) of prebiotics was decreased adherence of the tested strains observed on all types of substrate. The tested saccharides, which are part of the residual compounds of the used prebiotics, had a very similar effect-eliciting a decrease in adherence ability in the majority of the probiotic strains.

Automated acquisition of top-view dairy cow depth image data using an RGB-D sensor camera.

Animal dimensions are essential indicators for monitoring their growth rate, diet efficiency, and health status. A computer vision system is a recently emerging precision livestock farming technology that overcomes the previously unresolved challenges pertaining to labor and cost. Depth sensor cameras can be used to estimate the depth or height of an animal, in addition to two-dimensional information. Collecting top-view depth images is common in evaluating body mass or conformational traits in livestock species. However, in the depth image data acquisition process, manual interventions are involved in controlling a camera from a laptop or where detailed steps for automated data collection are not documented. Furthermore, open-source image data acquisition implementations are rarely available. The objective of this study was to 1) investigate the utility of automated top-view dairy cow depth data collection methods using picture- and video-based methods, 2) evaluate the performance of an infrared cut lens, 3) and make the source code available. Both methods can automatically perform animal detection, trigger recording, capture depth data, and terminate recording for individual animals. The picture-based method takes only a predetermined number of images whereas the video-based method uses a sequence of frames as a video. For the picture-based method, we evaluated 3- and 10-picture approaches. The depth sensor camera was mounted 2.75 m above-the-ground over a walk-through scale between the milking parlor and the free-stall barn. A total of 150 Holstein and 100 Jersey cows were evaluated. A pixel location where the depth was monitored was set up as a point of interest. More than 89% of cows were successfully captured using both picture- and video-based methods. The success rates of the picture- and video-based methods further improved to 92% and 98%, respectively, when combined with an infrared cut lens. Although both the picture-based method with 10 pictures and the video-based method yielded accurate results for collecting depth data on cows, the former was more efficient in terms of data storage. The current study demonstrates automated depth data collection frameworks and a Python implementation available to the community, which can help facilitate the deployment of computer vision systems for dairy cows.

Implementation of SARS-CoV-2 Monoclonal Antibody Infusion Sites at Three Medical Centers in the United States: Strengths and Challenges Assessment to Inform COVID-19 Pandemic and Future Public Health Emergency Use.

Monoclonal antibody therapeutics to treat coronavirus disease (COVID-19) have been authorized by the US Food and Drug Administration under Emergency Use Authorization (EUA). Many barriers exist when deploying a novel therapeutic during an ongoing pandemic, and it is critical to assess the needs of incorporating monoclonal antibody infusions into pandemic response activities. We examined the monoclonal antibody infusion site process during the COVID-19 pandemic and conducted a descriptive analysis using data from 3 sites at medical centers in the United States supported by the National Disaster Medical System. Monoclonal antibody implementation success factors included engagement with local medical providers, therapy batch preparation, placing the infusion center in proximity to emergency services, and creating procedures resilient to EUA changes. Infusion process challenges included confirming patient severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, strained staff, scheduling, and pharmacy coordination. Infusion sites are effective when integrated into pre-existing pandemic response ecosystems and can be implemented with limited staff and physical resources.

Real-world Effect of Monoclonal Antibody Treatment in COVID-19 Patients in a Diverse Population in the United States.

BACKGROUND: Monoclonal antibodies (mAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are a promising treatment for limiting the progression of coronavirus disease 2019 (COVID-19) and decreasing strain on hospitals. Their use, however, remains limited, particularly in disadvantaged populations. METHODS: Electronic health records were reviewed from SARS-CoV-2 patients at a single medical center in the United States that initiated mAb infusions in January 2021 with the support of the US Department of Health and Human Services' National Disaster Medical System. Patients who received mAbs were compared with untreated patients from the time period before mAb availability who met eligibility criteria for mAb treatment. We used logistic regression to measure the effect of mAb treatment on the risk of hospitalization or emergency department (ED) visit within 30 days of laboratory-confirmed COVID-19. RESULTS: Of 598 COVID-19 patients, 270 (45%) received bamlanivimab and 328 (55%) were untreated. Two hundred thirty-one patients (39%) were Hispanic. Among treated patients, 5/270 (1.9%) presented to the ED or required hospitalization within 30 days of a positive SARS-CoV-2 test, compared with 39/328 (12%) untreated patients (P < .001). After adjusting for age, gender, and comorbidities, the risk of ED visit or hospitalization was 82% lower in mAb-treated patients compared with untreated patients (95% CI, 56%-94%). CONCLUSIONS: In this diverse, real-world COVID-19 patient population, mAb treatment significantly decreased the risk of subsequent ED visit or hospitalization. Broader treatment with mAbs, including in disadvantaged patient populations, can decrease the burden on hospitals and should be facilitated in all populations in the United States to ensure health equity.

Opacification of hydrophilic MemoryLens U940A intraocular lenses: analysis of 2 explanted lenses.

PURPOSE: To determine the rate of opacification of hydrophilic MemoryLens U940A intraocular lenses (IOLs) (Mentor Ophthalmics, Inc.) in the given cohort and perform a histopathological and spectrophotometer analysis of 2 explanted opacified IOLs. SETTING: Ophthalmology Department, Faculty Hospital, Nitra, Slovakia. METHOD: This retrospective study comprised 182 patients (205 eyes) who had implantation of a MemoryLens U940A IOL from June 1997 to June 2000. The patients were examined using a slitlamp to detect the presence of IOL opacification. In 4 cases, the lenses were explanted because of significant opacification and patient-reported problems; 2 lenses were provided for further analysis. One unused reference MemoryLens U940A IOL was also evaluated. All IOL were stained with von Kossa to determine the presence of calcium in the opacification. To confirm the components presence of an ultraviolet (UV) absorber, the IOLs were examined with an Avatar 330 Fourier transfer infrared (IR) spectroscope and a UV visible spectrophotometer (Philips). The IR spectrums for the IOL were identified using an IR spectrum atlas. The opacified IOLs, reference IOL, and the IOL packaging were further examined to determine the presence of silicone. RESULTS: Various amounts of opacification were found on the MemoryLens U940A IOL in 30 eyes (30 patients) (14.63%). Two explanted IOLs were positive for von Kossa staining, proving the presence of calcium deposits; the reference lens staining was negative. Spectrophotometry showed that the reference IOL and opacified IOLs were of the same polymer. The presence of the UV absorber on the benzophenone base was seen in the reference lens but not the opacified IOLs. In contrast, an increased concentration of low-molecular-weight components generated during the degradation of the polymer was present in the opacified lenses. The white cover pf the IOL is of polydimethyl siloxane, a silicone rubber. However, no silicone rubber was present in any examined lens, perhaps because the IOLs were in contact with alcohol during the histopathologic examination. CONCLUSIONS: The results indicate opacification of the hydrophilic MemoryLens U940A was caused by premature consumption of the UV absorber in the polymer component of the IOLs optic, with a subsequent degradation of the polymer. Whether silicone from the white cover led to the IOL opacification, as reported with other types of hydrophilic IOLs, could not be confirmed.

An outbreak of Campylobacter enteritis associated with a community water supply on a U.S. military installation.

An outbreak of acute gastroenteritis involving 249 persons, 32% of whom were hospitalized, occurred on a U.S. Army installation in 1990. Campylobacter jejuni was isolated from 81 of 163 (50%) persons cultured. Seventeen isolates of C. jejuni available for serotyping were Lior serotype 5. The outbreak remained restricted to one recruit barracks area and adjacent Junior Reserve Officer Training Corps cadet barracks. Infection of sequential cohorts of recruits over an interval of 3 weeks suggested a continuing or intermittent common source. Contaminated food was not implicated because affected persons ate at separate dining facilities and other facilities with the same food sources had no associated illnesses. There was a strong association between the amount of water consumed by recruits and risk of diarrhea (chi-square test for trend, p<0.001). Samples of drinking water collected in the affected area had no residual chlorine and when cultured yielded greater than 200 colonies of coliform bacteria per 100 mL of water sampled. Although Campylobacter was not isolated from water, living and dead birds were found in an elevated water storage tank providing drinking water to the affected area. This and other similar outbreaks indicate that contamination of water storage tanks can lead to large outbreaks of Campylobacter enteritis.

Phosphorus removal in emergent free surface wetlands.

Constructed and natural wetlands are capable of absorbing new phosphorus loadings, and, in appropriate circumstances, can provide a low-cost alternative to chemical and biological treatment. Phosphorus interacts strongly with wetland soils and biota, which provide both short-term and sustainable long-term storage of this nutrient. Soil sorption may provide initial removal, but this partly reversible storage eventually becomes saturated. Uptake by biota, including bacteria, algae, and duckweed, as well as macrophytes, forms an initial removal mechanism. Cycling through growth, death, and decomposition returns most of the biotic uptake, but an important residual contributes to long-term accretion in newly formed sediments and soils. Despite the apparent complexity of these several removal mechanisms, data analysis shows that relatively simple equations can describe the sustainable processes. Previous global first order removal rates characterize the sustainable removal, but do not incorporate any biotic features. This article reviews the relevant processes and summarizes quantitative data on wetland phosphorus removal.

Nitrogen farming for pollution control.

The use of free water surface treatment wetlands for nitrate reduction has an extensive basis in data from dozens of operating systems. Marshes are effective for denitrification, with first order areal annual rate constants centered on thirty-four meters/year. Performance improves at higher water temperatures, with a modified Arrhenius temperature factor of 1.090. Performance also increases with increasing hydraulic efficiency, created by prevention of short-circuiting, and reflected in values of the tanks-in-series parameter N > 5. Higher efficiencies are associated with submergent and emergent soft tissue vegetation, and lower efficiencies with unvegetated open water and forested wetlands. Hydraulic loadings of 2-7 cm/day can produce 30% nitrate load reductions, over the temperature range 6-20 degrees C. Carbon availability limits denitrification at high nitrate loadings, however, wetlands produce carbon in sufficient quantities to support the loads anticipated in the upper midwest. The conversion of agricultural lands to treatment wetlands focused on nitrate reduction is termed nitrogen (N) farming. (D.H. Hey, Nitrogen farming: harvesting a different crop. Restoration Ecology, 2002, 10 (1), 1-11). A demonstration project is indicated to address local issues and scale-up considerations. Such a project would require thorough monitoring for the purpose of optimizing and refining design models. Significant ancillary benefits of ecological diversity and wildlife habitat are certain to accompany the project, but are of secondary importance until the water quality functions are demonstrated. Regulatory issues include permitting and wetland classification. Economic issues include proper pricing of services and methods of revenue generation. Resolution of these potential difficulties may require modification of existing policies and institutions.