A synergistic anti-bacterial and anti-adhesion activity of tea tree (Melaleuca alternifolia) and lemon eucalyptus tree (Eucalyptus citriodora Hook) essential oils on Legionella pneumophila.

Legionella pneumophila is a Gram-negative bacterial pathogen that colonizes natural and artificial water systems and has the ability to form a biofilm. The biofilm protects L. pneumophila from various environmental factors and makes it more resistant to chlorine-based disinfectants. This study investigated the anti-bacterial properties of tea tree (Melaleuca alternifolia (Maiden and Betche) Cheel) oil and lemon eucalyptus tree (Eucalyptus citriodora Hook) essential oils (EOs) and their synergistic, additive inhibitory and anti-adhesive effects against L. pneumophila biofilm formation on polystyrene. The minimum effective concentration (MEC) for tea tree is 12.8 mg ml-1 and for lemon eucalyptus tree EO 6.4 mg ml-1. In the checkerboard assay, different combinations of these two EO show synergistic and additive anti-microbial activity. The minimum anti-adhesive concentration (MAC) for tea tree is 12.8 mg ml-1 and for lemon eucalyptus tree EO 6.4 mg ml-1. A combination of 3.2 mg ml-1 tea tree EO and 0.8 mg ml-1 lemon eucalyptus tree EO showed the strongest anti-adhesive effect against L. pneumophila on polystyrene. The tested oils and their combination showed intriguing potential to inhibit L. pneumophila biofilm formation.

Toward sustainable household laundry. Washing quality vs. environmental impacts.

We tested the efficacy of standard soil removal and bacterial reduction from textile. A life cycle analysis for different washing cycles was also performed. The results show that washing at 40 °C and 10 g/L was the most effective and resulted in good removal of standard soiling. However, bacteria reduction was highest at 60 °C, 5 g/L and 40 °C, 20 g/L (> 5 log CFU/carrier). With the 40 °C, 10 g/L scenario, we approached the standard requirements for household laundry of ~ 4 log CFU/carrier reduction and good soil removal. Howsoever, life cycle analysis shows that washing at 40 °C and 10 g/L has a higher environmental impact than 60 °C and 5 g/L due to the significant contribution of the detergent. Reducing energy consumption and reformulation of detergents needs to be implemented in the household laundry to achieve sustainable washing without compromising the quality.

Strategies for Strengthening the Resilience of Public Health Systems for Pandemics, Disasters, and Other Emergencies.

OBJECTIVE: The aim of this study was to identify and prioritize strategies for strengthening public health system resilience for pandemics, disasters, and other emergencies using a scorecard approach. METHODS: The United Nations Public Health System Resilience Scorecard (Scorecard) was applied across 5 workshops in Slovenia, Turkey, and the United States of America. The workshops focused on participants reviewing and discussing 23 questions/indicators. A Likert type scale was used for scoring with zero being the lowest and 5 the highest. The workshop scores were analyzed and discussed by participants to prioritize areas of need and develop resilience strategies. Data from all workshops were aggregated, analyzed, and interpreted to develop priorities representative of participating locations. RESULTS: Eight themes emerged representing the need for better integration of public health and disaster management systems. These include: assessing community disease burden; embedding long-term recovery groups in emergency systems; exploring mental health care needs; examining ecosystem risks; evaluating reserve funds; identifying what crisis communication strategies worked well; providing non-medical services; and reviewing resilience of existing facilities, alternate care sites, and institutions. CONCLUSIONS: The Scorecard is an effective tool for establishing baseline resilience and prioritizing actions. The strategies identified reflect areas in most need for investment to improve public health system resilience.

Surface-active natural saponins. Properties, safety, and efficacy.

In the future, cleaning products must fulfil the principles of green chemistry while maintaining efficacy against bacteria. This study aims to evaluate the detergent properties, ecotoxicity, and anti-biofilm potential of natural saponins compared to synthetic surfactants. We tested sodium dodecyl sulphate, quillaja saponin, escin, and sapogenin for emulsifying capacity, critical micelle concentration, ecotoxicity to yeast, and antibacterial and anti-biofilm potential against bacteria. The results show that the emulsifying capacities of quillaja saponin and sodium dodecyl sulphate are similar, while the critical micelle concentration for quillaja saponin is much lower . Furthermore, the antibacterial and antibiofilm potentials are much higher for quillaja saponin than for synthetic sodium dodecyl sulphate . Moreover, we have shown that natural saponins are less toxic to the S. cerevisiae than synthetic saponin is. All these facts indicate that quillaja is a suitable candidate to replace synthetic products as it meets the requirements of efficacy and safety.

Cold plasma for sustainable control of hygienically relevant biofilms. The interaction of plasma distance and exposure time.

This study aimed to analyse the efficacy of a new cold plasma device adapted for treatment with a low power consumption . We tested the reduction of bacterial cells in biofilms of E. coli, S. aureus and P. aeruginosa. . The results show significant differences between bacterial cells, suggesting that Gramme-positive S. aureus is less susceptible to plasma treatment than Gramme-negative E. coli and P. aeruginosa. Increasing the exposure time and decreasing the distance decreases the number of cells in the biofilm. However, the combination of close distance and long exposure time resulted in synergistic effects. We demonstrated a reduction of up to 6.6 log CFU cm2 for E. coli at 1 mm and an exposure time of 60 seconds. All these indicate that the new cold plasma jet device can be an important key to ensuring hygiene and numerous applications in medicine and engineering are possible.

Mobilizing and Delivering Essential Meals to Children and Families Affected by School Closures During COVID-19 and Beyond.

BACKGROUND: The closure of schools in response to COVID-19 compromised access to essential meals for many students. The Emergency Meals-to-You program, a public/private partnership, was set up to address this challenge. More than 38.7 million meals were delivered between April and August 2020. This study explores lessons learned and identifies strategies for strengthening food access and security at schools and beyond. METHODS: Qualitative research methods were used. This included interviews and focus groups with participants involved in setting up and delivering the Emergency Meals-to-You program. Data were thematically analyzed using key phrases, ideas, and concepts, and interpreted. RESULTS: The program leveraged a multisectoral approach. Components relied on each other and included: schools, public/private partnership, eligibility, relationships, experience, centralized communication, food quality and branding, logistics, and transport. Strategies identified to strengthen food access focused on integration with emergency management structures, understanding food needs at the school level, building a fully procurable menu, and allowing distribution to be rapidly scaled. CONCLUSIONS: The lessons identified and strategies recommended provide a framework for working across the emergency management spectrum (school to national level) to strengthen food access and availability for students and their families affected by a pandemic, disaster, or crisis situation.

Predicting the outcomes of interpolyelectrolyte neutralization at surfaces on the basis of complexation experiments and vice versa.

This study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa. For this purpose, the correlation between the processes of complex and multilayer formation involving three pairs of vinylic polyions in solutions of binary 1 : 1 sodium salts (NaX; X = F, Cl, Br, I, NO3, ClO4) was explored by means of dynamic and electrophoretic light scattering, potentiometry, microcalorimetry, spectrophotometry and quartz crystal microbalance. The gradual reactant mixing in solution at lower salt concentrations resulted in a Fuoss-Sadek sequence of events (primary complexes → secondary complexes → 1 : 1 flocculate), whereby the obtained nano-complexes could be successively overcharged. At high salt concentration and with excess polycation present, metastable nano-complexes and precipitates containing surplus of positively charged monomers were formed. The amount of extrinsically compensated charge was in accord with the polycation affinities toward counteranions, established by monitoring the electrolyte-induced aggregation of positively charged nano-complexes. Perfect analogy with respect to counteranion influence on the amount of adsorbed polycation was noticed for corresponding multilayers. Aside from providing a deeper understanding of interpolyelectrolyte neutralization, the gained insights can also be used to steer the polyelectrolyte multilayer composition and properties.

Influence of Hydrogen Peroxide on Disinfection and Soil Removal during Low-Temperature Household Laundry.

In the Water, Energy and Waste Directive, the European Commission provides for the use of household washing programmes with lower temperatures (30-40 °C) and lower water consumption. However, low washing temperatures and the absence of oxidising agents in the liquid detergents, and their reduced content in powder detergents, allow biofilm formation in washing machines and the development of an unpleasant odour, while the washed laundry can become a carrier of pathogenic bacteria, posing a risk to human health. The aim of the study was to determine whether the addition of hydrogen peroxide (HP) to liquid detergents in low-temperature household washing allows disinfection of the laundry without affecting the properties of the washed textiles even after several consecutive washes. Fabrics of different colours and of different raw material compositions were repeatedly washed in a household washing machine using a liquid detergent with the addition of 3% stabilised HP solution in the main wash, prewash or rinse. The results of the antimicrobial activity, soil removal activity, colour change and tensile strength confirmed the excellent disinfection activity of the 3% HP, but only if added in the main wash. Its presence did not discolour nor affect the tensile strength of the laundry, thus maintaining its overall appearance.

Soft nanotechnology: the potential of polyelectrolyte multilayers against E. coli adhesion to surfaces.

Preventing bacterial attachment to surfaces is the most efficient approach to controlling biofilm proliferation. The aim of this study was to compare anti-adhesion potentials of 5 and 50 mmol/L polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4-styrenesulfonate), poly(4-vinyl-N-ethylpyridinium bromide)/ poly(sodium 4-styrenesulfonate), and poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4-styrenesulfonate) against Escherichia coli. Glass surface was covered with five polyelectrolyte layers and exposed to bacterial suspensions. Poly(4-vinyl-N-ethylpyridinium bromide)/poly(sodium 4-styrenesulfonate) was the most effective against bacterial adhesion, having reduced it by 60 %, followed by poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4- styrenesulfonate) (47 %), and poly(allylamine hydrochloride)/poly(sodium 4-styrenesulfonate) (38 %). Polyelectrolyte multilayers with quaternary amine groups have a significant anti-adhesion potential and could find their place in coatings for food, pharmaceutical, and medical industry.

Efficacy of sodium dodecyl sulphate and natural extracts against E. coli biofilm.

The aim of this study was to determine and compare the efficacy of a standard cleaning agent, sodium dodecyl sulphate, and natural extracts from pomegranate peel grape skin and bay laurel leaf against E. coli biofilm. The biofilm was exposed for 10 minutes to three different concentrations of each tested compound. The results show that bay laurel leaf extract is the most efficient with 43% biofilm biomass reduction, followed by pomegranate peel extract (35%); sodium dodecyl sulphate and grape skin extract each have 30% efficacy. Our study demonstrated that natural extracts from selected plants have the same or even better efficacy against E. coli biofilm removal from surfaces than the tested classical cleaning agent do. All this indicates that natural plant extracts, which are acceptable from the health and environment points of view, can be potential substitutes for classical cleaning agents.

Escherichia coli biofilm formation and dispersion under hydrodynamic conditions on metal surfaces.

The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E. coli, and biofilm formation and dispersion. The experiments were provided in a flow chamber simulating a cleaning-in-place system. Biofilm biomass was measured using a crystal violet dye method. The results show that hydrodynamic forces affect not only biofilm formation and dispersion but the multiplication of E. coli in the first place. We found more biofilm biomass on the rough surface than on the smooth one. The results of the biofilm formation test show that laminar flow promotes the biofilm growth over 72 h, meanwhile turbulent flow after 48 h causes decrease in biomass. The results of the biofilm dispersion test, in contrast, show that laminar flow removed less biofilm from both materials that turbulent flow did. Therefore, taking into account these findings in cleaning-in-place technology can substantially reduce E. coli multiplication and biofilm formation.

The influence of shear stress on the adhesion capacity of Legionella pneumophila.

Bacterial adhesion is a complex process influenced by many factors, including hydrodynamic conditions. They affect the transfer of oxygen, nutrients, and bacterial cells in a water supply and cooling systems. The aim of this study was to identify hydrodynamic effects on bacterial adhesion to and detachment from stainless steel surfaces. For this purpose we observed the behaviour of bacterium L. pneumophila in no-flow and laminar and turbulent flow conditions simulated in a fluid flow chamber. The bacterial growth in no-flow and laminar flow conditions was almost identical in the first 24 h, while at 48 and 72 h of incubation, the laminar flow stimulated bacterial growth. In the second part of this study we found that laminar flow accelerated bacterial adhesion in the first 48 h, but after 72 h the amount of bacterial cells exposed to the flow dropped, probably due to detachment. In the third part we found that the turbulent flow detached more bacterial cells than the laminar, which indicates that the strength of shear forces determines the rate of bacterial removal.

Bacterial adhesion capacity on food service contact surfaces.

The aim of this study was to analyse the adhesion of E. coli, P. aeruginosa and S. aureus on food contact materials, such as polyethylene terephthalate, silicone, aluminium, Teflon and glass. Surface roughness, streaming potential and contact angle were measured. Bacterial properties by contact angle and specific charge density were characterised. The bacterial adhesion analysis using staining method and scanning electron microscopy showed the lowest adhesion on smooth aluminium and hydrophobic Teflon for most of the bacteria. However, our study indicates that hydrophobic bacteria with high specific charge density attach to those surfaces more intensively. In food services, safety could be increased by selecting material with low adhesion to prevent cross contamination.

Symptomatic Response of the Elderly with Cardiovascular Disease during a Heat Wave in Slovenia.

OBJECTIVE: The aim of this study is to analyse the symptomatic response of elderly people to heat burden and indoor air quality exposure, and to create an index, the basis on which healthcare workers could react and prevent heat-related illnesses when the first symptoms appear. METHODS: The impact of the indoor thermal environment was studied with regards to Humidex and indoor air quality by CO2 concentrations on elderly people's symptomatic response. It was a natural experiment in which two different groups of elderly people (>65 years) were observed: the first group had a diagnosed cardiovascular disease, and the second group did not have the disease. RESULTS: The results show that the expression and aggravation of symptoms are related to an increase of heat burden and low indoor air quality. The symptoms under analysis do not have the same frequency distribution of intensity and, therefore, cannot be interpreted as a single universal symptom index. Instead, two indices must be created separately for both general and specific symptoms. CONCLUSIONS: Healthcare workers should be educated about the interactive influences of the thermal environment and the air quality on health. Unsuitable conditions could be ascertained by the nursing home occupants' symptomatic response.

Knowledge of health principles among professionals in Slovenian kindergartens.

OBJECTIVES: Preschool children have significant health issues. From the relevant legislation and regulations, it can be seen that kindergarten teachers (KTs) and kindergarten teacher assistants (KTAs) are expected to be familiarwith the basic hygienic measures and steps for preventing injuries and illnesses, to recognize infectious diseases, and to know how to give the first aid. To gain these skills, a continuous life-long learning is necessary, because the characteristics of diseases are changing. Study design: original research. METHODS: 45 kindergartens in Slovenia were randomly selected and a questionnaire with 17 questions on health themes was sent. An analysis was performed via SPSS 17.0, using descriptive methods and nonparametric χ2 tests. RESULTS: There were 774 participants, of whom 56% were KTs and 44% KTAs. The share of KTs and KTAs who consider their knowledge of health principles to be very good or excellent is 67%. Their estimation of first aid knowledge is lower. They are also well aware of the importance of health knowledge in their work; a total of 87% strongly agree with this. The results also show that they are familiar with hygiene principles. The χ2 test showed there are certain statistically characteristic connections between the age of teachers and their assistants, occupation and work experiences. CONCLUSIONS: Because children are a particularly vulnerable group, teachers can encounter injuries and sudden illnesses at their work. Supplementary education is necessary among skilled workers in educational institutions, including kindergartens.

Effects of natural antimicrobials on bacterial cell hydrophobicity, adhesion, and zeta potential.

Interactions between bacterial cells and contact materials play an important role in food safety and technology. As bacterial strains become ever more resistant to antibiotics, the aim of this study was to analyse adhesion of selected foodborne bacterial strains on polystyrene surface and to evaluate the effects of natural antimicrobials on bacterial cell hydrophobicity, adhesion, and zeta potential as strategies of adhesion prevention. The results showed strain-specific adhesion rate on polystyrene. The lowest and the highest adhesion were found for two B. cereus lines. Natural antimicrobials ferulic and rosmarinic acid substantially decreased adhesion, whereas the effect of epigallocatechin gallate was neglectful. Similar results were found for the zeta potential, indicating that natural antimicrobials reduce bacterial adhesion. Targeting bacterial adhesion using natural extracts we can eliminate potential infection at an early stage. Future experimental studies should focus on situations that are as close to industrial conditions as possible.

Microbial adhesion capacity. Influence of shear and temperature stress.

Environmental parameters dictate the conditions for both biofilm formation and deconstruction. The aim of this study is to analyse the impact of hydrodynamic and thermodynamic effects on bacterial detachment. Escherichia coli grown on two stainless steel metal surfaces with different roughness (brushed with roughness of 0.05 µm and electropolished with roughness of 0.29 µm) are exposed to laminar and turbulent (shower) flows of phosphate buffered saline media at temperatures of 8, 20 and 37 °C. Results show that the turbulent flow removes significantly more bacterial cells than laminar flow (p <0.05) on both materials. This indicates that the shear force determines the rate of detached bacteria. It is also observed that detachment of cells is more efficient on brushed than on electropolished contact surfaces because on the latter surface, fewer cells were attached before exposure. Moreover, we demonstrate that the temperature of the washing agent has an impact on bacterial detachment. At the same flow conditions, the exposure to higher temperature results in greater detachment rate.

Bioaccessibility of lead in sand intended for playground sandboxes in Slovenia: a preliminary study.

Slovene press has recently expressed concern for the health of children who ingest playground sand contaminated with lead. However, current assessments may be overestimating the health risk, as they assume that human body absorbs the whole amount of a contaminant. The aim of our study was to see how much lead in sand intended for playground sandboxes in Slovenia really is absorbed and what health risk it may present. To do that, we ran bioaccessibility tests to simulate metabolism and see how digestion affects lead levels. Our results show low bioaccessibility of lead from sand (0.01- 36.84 %). Taking into account lead bioaccessibility, we ran several scenarios of sand ingestion in children and established that in general the risk is negligible, except for pica behaviour with extremely high (20 g) ingestion of sand with highly mobilised lead (2.69 µg g⁻¹). Further research should assess real-life exposure to lead from playground sand in children and perhaps update these preliminary bioaccessibility data.

The protective role of antioxidants in the defence against ROS/RNS-mediated environmental pollution.

Overproduction of reactive oxygen and nitrogen species can result from exposure to environmental pollutants, such as ionising and nonionising radiation, ultraviolet radiation, elevated concentrations of ozone, nitrogen oxides, sulphur dioxide, cigarette smoke, asbestos, particulate matter, pesticides, dioxins and furans, polycyclic aromatic hydrocarbons, and many other compounds present in the environment. It appears that increased oxidative/nitrosative stress is often neglected mechanism by which environmental pollutants affect human health. Oxidation of and oxidative damage to cellular components and biomolecules have been suggested to be involved in the aetiology of several chronic diseases, including cancer, cardiovascular disease, cataracts, age-related macular degeneration, and aging. Several studies have demonstrated that the human body can alleviate oxidative stress using exogenous antioxidants. However, not all dietary antioxidant supplements display protective effects, for example, ß-carotene for lung cancer prevention in smokers or tocopherols for photooxidative stress. In this review, we explore the increases in oxidative stress caused by exposure to environmental pollutants and the protective effects of antioxidants.

Health impact assessment of liquid biofuel production.

Bioethanol and biodiesel as potential substitutes for fossil fuels in the transportation sector have been analyzed for environmental suitability. However, there could be impacts on human health during the production, therefore adverse health effects have to be analyzed. The aim of this study is to analyze to what health risk factors humans are exposed to in the production of biofuels and what the size of the health effects is. A health impact assessment expressed as disability adjusted life years (DALYs) was conducted in SimaPro 7.1 software. The results show a statistically significant lower carcinogenic impact of biofuels (p < 0.05) than fossil fuels. Meanwhile, the impact of organic respirable compounds is smaller for fossil fuels (p < 0.05) than for biofuels. Analysis of inorganic compounds like PM10,2.5, SO2 or NO(x) shows some advantages of sugar beet bioethanol and soybean biodiesel production (p < 0.05), although production of sugarcane bioethanol shows larger impacts of respirable inorganic compounds than for fossil fuels (p < 0.001). Although liquid biofuels are made of renewable energy sources, this does not necessary mean that they do not represent any health hazards.