Search Results (672)

This study investigated the influence of two years of ultrafiltration (UF) on the separation properties of tubular polyvinylidene fluoride membranes used for treating carwash wastewater, particularly with regard to bacterial rejection. Fouling was mitigated by washing the membranes with alkaline cleaning agents (pH > 11.5). Repeated applications of these agents enlarged the membrane pores to approximately 300 nm. This affected bacterial retention, and for feed containing bacteria (determined as colony-forming units, CFU) at a concentration of 3.11 × 10⁶ CFU/mL, over 13,000 CFU/mL were detected in the permeate. Interestingly, fouling improved retention, reducing bacterial counts present in the permeate from 13,689 to 2889 CFU/mL. Fouling also enhanced the retention of surfactants (80%), chemical oxide domain (60%), and turbidity (below 0.5 NTU), yielding results comparable to new membranes. Daily 60-min membrane washing with Wheel Cleaner solution (pH = 11.5) improved the membranes performance; however, it did not remove deposits from large pores, allowing good rejection performance and a permeate flux of 65 LMH to be maintained. It was found that bacteria also developed on the permeate side. Disinfection of the module housing with a NaOH/NaOCl solution reduced the number of bacteria in the permeate from 5356 to 66 CFU/mL. Microbiological tests revealed that some of these bacteria were antibiotic-resistant. Full article

Antimicrobial resistance (AMR) can disseminate through effluents from seafood processing facilities (SPFs), posing environmental and public health risks. This study assessed changes in coliform load and antimicrobial resistance patterns in effluents from two SPFs in Tema, Ghana, before and after upgrades to effluent treatment systems between 2022 and 2024. A total of 19 effluent samples were collected per SPF in 2021–2022, 20 effluent samples each per SPF in 2024, and 8 potable water samples each per SPF in 2024. Median coliform counts declined significantly in both facilities (SPF-1: 920 to 35 MPN/100 mL; SPF-2: 280 to 9.5 MPN/100 mL; p < 0.001), representing a 96% overall reduction. Escherichia coli prevalence decreased markedly in SPF-2, although Pseudomonas aeruginosa emerged after treatment upgrades. Resistance to third-generation cephalosporins and multidrug resistance declined, particularly in SPF-1, but persisted across both facilities. Potable water used for seafood processing showed low but detectable coliform contamination. Despite substantial reductions in coliform bacterial load, the continued presence of resistant gram-negative bacteria highlights the need for sustained AMR surveillance, mandatory effective effluent treatment, and routine disinfection of potable water to protect public health. Full article

The characterization of environmental Pseudomonas spp. from pharmaceutical industries is a relatively underexplored area of research. This study used 40 isolates of Pseudomonas from a pharmaceutical company that had been presumptively identified as Pseudomonas aeruginosa by VITEK^®2. The isolates were characterized using 16S rRNA sequencing, Multilocus Sequence Typing (MLST), Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass (MALDI–TOF MS), Fourier Transform Infrared (FT-IR) spectroscopy, ERIC-PCR, antimicrobial susceptibility profiling, and biofilm formation assessment on stainless steel surfaces. Twenty isolates were confirmed as P. aeruginosa. Sixteen isolates were only identified to the genus level of Pseudomonas, and the remaining four isolates were identified as Enterococcus faecalis (n = 2), Proteus spp. (n = 1), and Staphylococcus saprophyticus subsp. bovis/S. edaphicus/S. saprophyticus subsp. saprophyticus/S. pseudoxylosus/S. xylosus/S. caeli/S. ureilyticus. Typing of the 20 P. aeruginosa strains yielded 18 distinct FT-IR profiles and 19 ERIC-PCR profiles. The MLST analysis identified eight new sequence types (ST4292–ST4299). All strains were classified as multidrug-resistant (MDR), exhibiting resistance to multiple antimicrobial classes. Biofilm formation was observed in 28 (77.8%) Pseudomonas spp. strains on polystyrene surfaces, classified as moderately or strongly adherent, while all P. aeruginosa strains formed biofilms on stainless steel. Of the three disinfectants tested, sodium hypochlorite at 0.01% showed the best performance, reducing or eliminating biofilm formation in 24 (85.7%) strains. The regular evaluation of disinfection effectiveness in pharmaceutical industries is essential, as the presence of biofilm-forming strains can compromise production and contaminate final products. Full article

Titanium compounds are an integral component for paint pigments, food additives (E171), catalysts, precursors for resistant structural materials, medicine, and water, and air purification and disinfection processes. A new and rather promising trend for titanium dioxide production is obtaining it from minerals with magnesium titanium structure. Magnesium titanates obtained by pyrometallurgical processing of quartz–leucoxene concentrate (oil sandstones). It was found that the optimal pyrometallurgical processing conditions were 4 h and a temperature of 1425–1450 °C, with TiO₂ → Mg_XTi_YO_Z conversion exceeding 95%, and that sulfation of the magnesium titanate mixture with 60–70% H₂SO₄ for 150–210 min allows a 95% extraction of titanium compounds into solution. Investigation of the mechanism of titanium compound precipitation from Mg-Ti-containing sulfuric acid solutions revealed that in the pH range from 3 to 6, only titanium compounds were extracted from solution, while coprecipitation of magnesium compounds begins only at pH above 6.5. The product obtained by precipitation is titanium dioxide with an anatase structure, with particle distribution ranging from 0.8 to 5.0 µm and a developed surface area over 250 m²/g with mesopores characteristic of sorption materials. Full article

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) remains a major challenge in healthcare settings due to its persistence on inanimate surfaces and resistance to conventional cleaning methods. Bacteriophages (phages) represent a promising biocontrol option owing to their high specificity and lytic activity. Methods: This study evaluated the use of a personal hand-held vibrating mesh nebulizer (VMN) as a rapid and localized delivery platform for phage aerosols. Using two lytic phages (ϕ2, Podovirus; ϕ11, Myovirus), we assessed phage stability under different storage conditions, viability during VMN operation, and surface decontamination efficacy under varying spray parameters. Results: In saline, both phages showed optimal long-term stability at 4 °C, whereas storage at −20 °C resulted in a progressive reduction in infectivity exceeding 3 logs over the storage period. VMN aerosolization did not compromise viability. A 3 min spray achieved >99.9% surface reduction: ϕ2 was effective at 1 × 10⁷ PFU/mL, whereas ϕ11 required 1 × 10⁸ PFU/mL. Importantly, residual ϕ2 activity persisted for at least 24 h, preventing detectable recolonization under the assay conditions, while ϕ11 protection was limited to 6 h. Conclusions: These findings establish the hand-held sprayer as a practical, low-cost, and flexible approach to deliver viable phage aerosols, providing an effective complement to large-scale disinfection systems and offering a targeted strategy to enhance infection control in healthcare environments. Full article

In hospitals with limited resources, chlorine solutions are commonly used for biocleaning. The effectiveness of these solutions depends on the concentration of active chlorine and how they are prepared and stored. A study conducted in six University Hospitals in Benin from 10 March to 11 July 2025 aimed to evaluate the stability of active chlorine and the bactericidal efficacy of chlorine solutions used for disinfecting hospital environments. A total of 103 samples were analyzed using iodometric titration following the AFNOR (Association Française de Normalisation) standard NF EN ISO 7393-3 (2000) and WHO (World Health Organization) recommendations. Bactericidal activity was tested on multi-resistant hospital strains using the germ carrier method based on the standard NF T72-281. The study revealed that 88.4% of the solutions had inadequate active chlorine concentrations. Overall, the bactericidal activity was low, with only 14.6% effectiveness compared to 85.4% ineffectiveness. Ineffectiveness was particularly pronounced against Gram-negative bacilli, with 79.6% ineffectiveness and 20.4% effectiveness. Similarly, Gram-positive cocci showed a high level of ineffectiveness, reaching 84.5%, corresponding to 15.5% effectiveness. A significant association was observed between compliance with active chlorine concentrations and bactericidal effectiveness, with an OR of 42.5 and a p-value below 0.000001. Factors contributing to inefficiency included storage without light protection, use of transparent containers, storage for more than two days, inadequate active chlorine concentration, and incorrect pH levels. These issues compromise hospital disinfection and contribute to the persistence of multi-resistant bacteria in the hospital environment. Full article

This study investigates the effectiveness of cold atmospheric plasma (CAP) treatment for improving the microbiological and physicochemical quality of wastewater generated in tourism-affected coastal regions. Experiments were performed on influent and effluent samples from the Ravda Wastewater Treatment Plant (WWTP) collected in April, August, and November 2024, representing different seasonal loading conditions. The plasma pre-treatment of influent aimed to minimize toxic micropollutants that inhibit activated sludge activity, reduce pathogenic and opportunistic microorganisms, and enhance oxidative potential before biological processing. The post-treatment of effluent focused on the elimination of residual pathogens, mainly Enterobacteriaceae, and the oxidative degradation of xenobiotics resistant to conventional treatment. Combined fluorescent (CTC/DAPI) and culture-based analyses were used to assess microbial viability and activity. Plasma exposure (1, 3 and 5 min) caused measurable changes in metabolic potential and bacterial abundance across all sampling periods. The results demonstrate that 1 min CAP treatment does not increase pathogen removal, but enhances oxidation capacity of the influent, while 3 min of CAP treatment ensures the disinfection of the effluent. Both can be combined to improve the effluent safety prior to Black Sea discharge. CAP is showing strong potential as a sustainable technology for wastewater management in tourism-intensive coastal zones. Full article

Background/Objectives: Candida biofilms exhibit high resistance to antifungal treatment, motivating investigation of adjunctive physical disinfection methods. To quantitatively assess the effect of Er:YAG laser fluence on growth inhibition and viability of single-species Candida biofilms in vitro using a 7 mm full-beam handpiece. Methods: Biofilms of Candida albicans ATCC 10231, C. glabrata ATCC 90030, C. parapsilosis ATCC 22019, and C. krusei ATCC 6258 were grown on Sabouraud agar. In phase 1, growth inhibition zones (GIZs) were evaluated after non-contact Er:YAG irradiation (2 Hz, 300 µs, 10 mm distance, no air or water spray) at fluences from 0.3 to 3.4 J/cm², with incubation for 24 to 96 h. In phase 2, 96 h mature biofilms were irradiated for 120 s at 0.8, 1.0, 1.5, or 2.0 J/cm², and viability was quantified by colony-forming unit (CFU) imprinting. All experimental conditions were tested in quadruplicate. Results: GIZ diameters increased significantly with fluence for all species (p < 0.05) and remained stable up to 96 h. At the highest fluence, mean GIZs reached approximately 8.0 mm for C. albicans, 7.7 mm for C. parapsilosis, 7.0 mm for C. krusei, and 5.2 mm for C. glaxfbrata. In mature biofilms, CFU counts decreased significantly with increasing fluence (p < 0.05). For C. albicans, CFUs were reduced from 164.0 ± 25.1 at 0.8 J/cm² to 16.5 ± 5.2 at 2.0 J/cm², while C. glabrata decreased from 103.5 ± 5.4 to 20.8 ± 1.7. C. parapsilosis and C. krusei showed maximal reductions at 1.0–1.5 J/cm², followed by partial CFU rebound at 2.0 J/cm². Conclusions: Er:YAG irradiation delivered over a large, uniformly illuminated area induces stable, fluence-dependent inhibition and significant reduction of Candida biofilm viability in vitro. Optimal fluence ranges are species specific, underscoring the need for parameter optimization and further evaluation in more complex biofilm models before clinical extrapolation. Full article

Brachyspira hyodysenteriae is the primary cause of swine dysentery, characterized by bloody to mucoid diarrhea due to mucohaemorhagic colitis in pigs. The disease primarily affects pigs during the growth and finishing stage. The control and prevention of B. hyodysenteriae consists of the administration of antimicrobial drugs, in addition to management and adapted feeding strategies. A worldwide re-emergence of the disease has recently been reported with an increasing number of isolates demonstrating decreased susceptibility to several crucially important antimicrobials in the control of swine dysentery. This compromises the possibilities to eradicate B. hyodysenteriae from infected pig farms. A novel non-antibiotic zinc chelate has been reported to demonstrate positive effects on fecal quality and consistency, general clinical signs, average daily weight gain, and B. hyodysenteriae excretion during and after a 6-day oral treatment. The objective of the present study was to evaluate the zinc chelate (IntraDysovinol^® 499 mg/mL; IntraCare) within an eradication schedule with naturally occurring swine dysentery due to B. hyodysenteriae resistant to pleuromutilins under field conditions in Belgium. We evaluated a 14-day treatment schedule combined with alternative management measures (including partial depopulation of post-weaning facilities and improved external and internal biosecurity measures) and thorough cleaning and disinfection (including 2% NaOH) of the buildings and the sows from day 7 of treatment onwards. This alternative approach for B. hyodysenteriae eradication was evaluated on 18 pig farms over a 5-year period. All enrolled eradication programs were evaluated as successful at least 6–9 months after the finalization of the protocol. In conclusion, the zinc chelate product has an excellent potential for application within an eradication protocol of B. hyodysenteriae that are diagnosed as resistant to pleuromutilins. The combined approach of zinc chelate treatment and alternative management measures is demonstrated to be successful in the eradication of farrow-to-wean, farrow-to-finish, and finishing pig farms under field conditions in Belgium. Full article

Bacterial contaminants in ambulances could have a major impact on morbidities, mortalities, and healthcare resources, especially if these bacteria are antimicrobial-resistant. As far as we know, this is the first study in Al-Qassim region to evaluate the prevalence of bacterial contaminants in swab samples obtained from ambulances from Alqwarah General Hospital, Al-Qassim region, Saudi Arabia as an indicator for evaluation of the implemented infection control measures, and screen the antibiotics profiles of the isolates against the most regularly used antimicrobials. In total, 204 samples were collected from the ambulances following patient transport. To evaluate the effect of vehicle decontamination, 204 swabs were collected from the same sites of the ambulances immediately after cleaning and disinfection. The isolates were identified using standard bacteriological and biochemical methods, as recommended by the Clinical Laboratory Standard Institute (CLSI). The antibiotic susceptibility patterns were assessed using the Kirby–Bauer disc diffusion method. The prevalence of bacterial contamination in the samples collected following patient transport was 46.08%. In total, 83.33%, 75.00%, and 66.66% of the samples collected from DC shock apparatuses, ceilings, and emergency personnel seats, respectively, were contaminated. Furthermore, ceilings, DC shock apparatuses, emergency personnel seats, cervical collars, and monitors were found to harbor 10.8%, 9.8%, 7.8%, 6.8%, and 6.8% of the 102 bacterial isolates, respectively. Gram-positive organisms represented 96.1% of all bacterial isolates. Bacillus spp. was the most common isolate, accounting for 60.8% of all bacterial isolates. Although Pseudomonas aeruginosa and Proteus spp. isolates were sensitive to all the tested antimicrobials, many Gram-positive bacterial isolates were resistant to some antibiotics in variable frequencies. After 48 h of aerobic incubation (with or without 5–10% CO₂) on nutrient, blood, chocolate, and MacConkey agar plates at 37 °C, no bacterial growth was detected in the samples collected immediately following cleaning and disinfection. This is the second Saudi study to evaluate the prevalence of bacterial contaminants in Saudi Arabian ambulances, and it could help health policy makers in improving the implemented infection prevention and control measures in Saudi Arabian ambulances. The samples taken after patient transport revealed bacterial contaminants with varying rates of antimicrobial resistance. Policies ensuring the optimal cleaning and disinfection of ambulances can minimize the potential of bacterial infection for high-risk patients, their relatives, and healthcare providers. Full article

Managing bacterial infections and the spread of microbial resistance is one of the most critical and complex tasks of modern healthcare infrastructures. Antiseptics and disinfectants such as biocides play a significant role in controlling microbial resistance by reducing the microbial load on surfaces, skin, and environments, thereby limiting the opportunity for pathogens to proliferate and develop resistance. Herein, we tested the different interactions of quaternary ammonium compound (QAC)-based biocide compositions in pursuit of a better antimicrobial performance. An extensive microbiological analysis was conducted for 12 selected compositions of various combinations of mono-QACs, bis-QACs, and alcohols on 17 strains of bacteria of the ESKAPEE group and fungi, including 11 clinical highly resistant varieties, highlighting synergistic or additive dynamics. The evaluation showed noticeable improvements in activity, with up to 16-fold MBC and 32-fold MBEC reductions for alcohol-based compositions of lead QAC. Moreover, synergistic interactions were detected and confirmed via an optimized checkerboard assay for pyridinium QAC combinations against planktonic Gram-positive S. aureus with a fractional inhibitory concentration index (FICI) and fractional bactericidal concentration index (FBCI) of 0.39–0.5 and Gram-negative A. baumannii biofilms. The studied biocides demonstrated the long-term preservation of antimicrobial efficiency without resistance development during a 40-day period and do not induce QAC-associated cross-resistance for four commercially available antibiotics with similar mechanisms of action. Full article

Background: Surface contamination in healthcare environments plays a key role in the persistence and transmission of microorganisms. Long-lasting antimicrobial coatings based on copper–polymer complexes offer a promising passive strategy to minimize environmental contamination and healthcare-associated infections. Methods: This study evaluated a copper-alloy polymeric tape through physicochemical, in vitro, and hospital-based assessments. Structural analyses (XRD, Raman, SEM, EDX) were used to characterize the material, while antimicrobial efficacy was determined against Gram-positive and Gram-negative bacteria following ISO 22196:2011. A randomized 19-week clinical study was conducted in the Emergency and Urgent Unit of the University Hospital of Brasília to quantify microbial loads on high-touch surfaces covered with the copper-alloy tape or a non-antimicrobial control. Results: Structural characterization techniques validated the integrity and heterogeneous distribution of copper within the polymeric matrix. All tested bacterial strains exhibited complete growth inhibition on the copper-alloy tape, with final counts consistently below the detection threshold (<1.00 log10 CFU/mL). Human keratinocytes analyzed by SEM showed preserved morphology. In hospital conditions, treated surfaces maintained significantly lower microbial loads than controls over 19 weeks. The number of yeast-positive samples was small compared to the total number of samples collected during the study, but Candida parapsilosis was the most frequently identified species. Conclusions: These findings support its use as a sustainable intervention to reduce environmental contamination and infection risks in healthcare settings. Full article

Failure of the endodontic treatment is often associated with persistent polymicrobial biofilms, particularly those involving Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans), which display synergistic pathogenicity and resistance to standard disinfection methods. This in vitro study compared the antimicrobial activity and oxidative damage induced by indocyanine green (ICG)–mediated laser ablation (LA) with that produced by antimicrobial photodynamic therapy (aPDT) using methylene blue (MB) or curcumin (CUR) in root canals infected with dual-species biofilms. The samples were divided into five experimental groups (n = 20): Group A—Methylene Blue + Red Laser (RL), Group B—Curcumin + Blue LED (BL), Group C—Indocyanine Green + Infrared Diode Laser (DL), Group D—saline solution (Negative Control—NC), Group E—2.5% sodium hypochlorite (Positive Control—PC). One hundred treated bovine incisors (20 per group) were analyzed for microbial viability (colony-forming unit (CFU/mL)), the metabolic functionality of biofilms was assessed through the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) based reduction method, and oxidative stress markers, including Thiobarbituric Acid Reactive Substances (TBARS), protein carbonyl content, total oxidant capacity (TOC), and total protein levels. All experimental treatments significantly reduced microbial load compared to the negative control (p < 0.05), with ICG achieving the greatest reduction. ICG also induced the highest levels of oxidative stress across all parameters (p < 0.05). These findings suggest that LA with ICG is more effective than aPDT with MB or CUR, achieving disinfection outcomes comparable to those of 2.5% sodium hypochlorite, and warrant further investigation in complex clinical models. Full article

The aim of this paper is to investigate the measures adopted by higher education institutions (HEIs) for sustainable water management in university campuses. Rain and storm water harvesting and treatment, rain and storm water reuse, wastewater treatment and reuse and technologies for runoff reduction were found to be frequently undertaken. Sustainable approaches to water supply such as water-efficient appliances, irrigation algorithms and the use of drought-resistant plants have been adopted as well. In support, monitoring of consumed water and of rain and storm waters has been a widespread practice. Important considerations were given to the impact of the identified measures on campuses’ energy consumption and greenhouse gas emissions. Nature-based solutions, employment of renewable energies and sustainable disinfection methods are measures to prioritize. Some wastewater technologies may deserve priority in virtue of their positive contribution to circular economy. Drawbacks such as groundwater and soil contamination due to wastewater reuse and the release of pollutants from fertilized nature-based technologies were identified. Despite their variety, it must be noted that many of these measures have generally involved rather limited portions of campuses, taken more for demonstration or pilot/full-scale research purposes. Additional measures not identified in the current review—for instance the prevention of pollution from micropollutants and waste mismanagement—should be implemented to boost HEIs’ environmental sustainability. The findings of this review pave the way for a more structured implementation of water sustainability measures in university campuses. Full article

Rare-earth oxide (REO) nanoparticles (NPs)—such as cerium (CeO₂), samarium (Sm₂O₃), neodymium (Nd₂O₃), terbium (Tb₄O₇), and praseodymium (Pr₂O₃)—have demonstrated strong antimicrobial activity against multidrug-resistant bacteria. Their effectiveness is attributed to unique physicochemical properties, including oxygen vacancies and redox cycling, which facilitate the generation of reactive oxygen species (ROS) that damage microbial membranes and biomolecules. Additionally, electrostatic interactions with microbial surfaces and sustained ion release contribute to membrane disruption and long-term antimicrobial effects. REOs also inhibit bacterial enzymes, DNA, and protein synthesis, providing broad-spectrum activity against Gram-positive, Gram-negative, and fungal pathogens. However, dose-dependent cytotoxicity to mammalian cells—primarily due to excessive ROS generation—and nanoparticle aggregation in biological media remain challenges. Surface functionalization with polymers, peptides, or metal dopants (e.g., Ag, Zn, and Cu) can mitigate cytotoxicity and enhance selectivity. Scalable and sustainable synthesis remains a challenge due to high synthesis costs and scalability issues in industrial production. Green and biogenic routes using plant or microbial extracts can produce REOs at lower cost and with improved safety. Advanced continuous flow and microwave-assisted synthesis offer improved particle uniformity and production yields. Biomedical applications include antimicrobial coatings, wound dressings, and hybrid nanozyme systems for oxidative disinfection. However, comprehensive and intensive toxicological evaluations, along with regulatory frameworks, are required before clinical deployment. Full article