Search Results (581)

Disinfection by ultrasound and carbon nanotubes (CNTs) provides attractive alternatives to conventional methods for water and wastewater treatment. This study explored the inactivation of Escherichia coli (E. coli) by 5 mg/L pristine short and long multi-walled CNTs (MWCNTs) and 20 kHz ultrasound individually or in combinations in DI water, Suwannee River natural organic matter (SRNOM), and sodium dodecyl sulfate (SDS) solution, respectively. The results indicated that the dispersity of MWCNTs was the single most important factor determining the inactivation rate of E. coli. The dispersity of short MWCNTs in solutions increased in the order of DI water <10 mgC/L SRNOM < 2 mM SDS. Correspondingly, the greatest log inactivation of E. coli was achieved in SDS when short MWCNTs were used alone (0.67 ± 0.12) and combined with ultrasound (1.80 ± 0.02) for 10 min. Short MWCNTs alone had a slightly greater inactivation (0.29 ± 0.07) in SRNOM solution than in DI water (0.18 ± 0.05). However, long MWCNTs had a slightly higher inactivation in DI water (0.24 ± 0.03) than short ones (0.18 ± 0.05), because of better dispersity in DI. The observed synergistic inactivation when ultrasound and short MWCNTs were used together in 2 mM SDS shows that ultrasound energized the MWCNTs more effectively when they were well dispersed, although SDS and MWCNTs can occupy the reaction sites at the cavitational bubble–water interfacial regions and scavenge •OH radicals. The results suggest that sonophysical effects are more important to inactivate E. coli than sonochemical effects. Ultrasound inactivates E. coli and/or energizes MWCNTs through the mechanisms of acoustic streaming, microstreaming, microstreamers, transient cavitation collapse-generated shock waves and microjets (transitional forms), and localized hot temperatures. The results of this study indicate that the cytotoxicity of CNTs includes impinging bacterial cells and/or direct contact with the bacteria. Full article

Bacterial diseases are a major constraint to aquaculture productivity, driving extensive antibiotic use and raising concerns over antimicrobial resistance, environmental contamination, and food safety. Curcumin, a polyphenolic compound from Curcuma longa, exhibits broad-spectrum antimicrobial and immunomodulatory activities but is limited by poor water solubility, instability, and low bioavailability. This review was conducted through a literature search of Scopus, PubMed, Web of Science, and Google Scholar using targeted keywords, including curcumin nanoparticles, antibacterial, aquatic pathogens, nanotechnology, synthesis, and disease control. Titles and abstracts were screened for relevance, followed by full-text evaluation of selected studies. Key findings were critically analyzed and incorporated into the review. Findings from the literature indicate that curcumin nanoparticles, synthesized via milling, anti-solvent precipitation, ionic gelation, emulsification, spray drying, and metal/polymer nanocomposite formation, exhibit enhanced antibacterial activity against aquatic pathogens, including Aeromonas hydrophila, Vibrio parahaemolyticus, Escherichia coli, and Staphylococcus aureus. Optimally engineered curcumin nanoparticles (<100 nm, being mostly spherical, highly negatively charged) can penetrate bacterial membranes, disrupt biofilms, lower minimum inhibitory concentrations, and improve in vivo fish survival. Practical applications include dietary supplementation to boost fish immunity and growth, water disinfection to reduce pathogen loads, immersion therapy for external infections, and antimicrobial coatings for aquaculture equipment and surfaces, resulting in reduced infections and outbreaks, reduced mortality, improved water quality, and decreased antibiotic dependence. In conclusion, curcumin nanoparticles and curcumin-based nanocomposites present a versatile, eco-friendly approach to sustainable aquaculture disease management. However, further field-scale validation, safety assessment, and cost-effective production methods are necessary to enable commercial adoption. Full article

Hospital-acquired infections (HAIs) remain a major clinical and economic burden, with pathogens such as Escherichia coli contributing to high rates of morbidity and mortality. Traditional manual disinfection methods are often insufficient, particularly in high-risk hospital environments. In this study, we investigated innovative strategies to enhance surface decontamination and reduce infection risk. First, we assessed the efficacy of the SMEG BPW1260 bedpan washer-disinfector, a thermal disinfection system for human waste containers. Our results demonstrated a reduction in Clostridium difficile and Escherichia coli contamination by >99.9% (>3 log reduction), as measured by colony-forming units (CFU) before and after treatment. Molecular techniques, including spectrophotometry, cell counting, and quantitative PCR (qPCR) for DNA quantification, confirmed reduction in bacterial contamination. Specifically, Clostridium difficile showed a reduction of approximately 89% in both optical density (OD) and cell count (cells/mL). In the case of Escherichia coli, a reduction of around 82% in OD was observed, with an even more pronounced decrease in cell count, reaching approximately 99.3%. For both bacteria, DNA quantification by qPCR was below detectable limits. Furthermore, we optimized the energy efficiency of the disinfection cycle, achieving a 45% reduction in power consumption compared to standard protocols without compromising antimicrobial efficacy. Secondly, we developed a sustainable cleaning solution based on methyl ester sulfonate surfactants derived from waste cooking oil. The detergent’s antibacterial activity was tested on contaminated surfaces and further enhanced through the incorporation of nanoassemblies composed of silver, electrostatically bound either to biomimetic magnetic nanoparticles or to conventional magnetic nanoparticles. Washing with the detergent alone effectively eliminated detectable contamination, while the addition of nanoparticles inhibited bacterial regrowth. Antimicrobial testing against E. coli revealed that the nanoparticle-enriched formulations reduced the average MIC values by approximately 50%, with MIC₅₀ values around 0.03–0.06 mg/mL and MIC₉₀ values between 0.06 and 0.12 mg/mL, indicating improved inhibitory efficacy. Finally, recognizing the infection risks associated with intra-hospital transport, we tested the SAFE-HUG Wheelchair Cover, a disposable non-woven barrier designed to reduce patient exposure to contaminated wheelchair surfaces. Use of the cover resulted in a 3.3 log reduction in surface contamination, based on viable cell counts. Optical density and bacterial DNA were undetectable in all covered samples at both 1 and 24 h, confirming the strong barrier effect. Together, these approaches—thermal no-touch disinfection, eco-friendly detergent boosted with nanoparticles, and protective transport barriers—respond to the urgent need for effective, sustainable infection control methods in healthcare settings. Our findings demonstrate the potential of these systems to counteract microbial contamination while minimizing environmental impact, offering promising solutions for the future of infection prevention in healthcare settings. Full article

The growing prevalence of bacteria resistant to antibiotics and conventional disinfectants is a cause for concern and underscores the necessity of developing new strategies to prevent the transmission of microorganisms. To this end, nanocrystalline Cu, Au, and Ag nanoparticles were employed to fabricate various coatings using the sputtering technique. Then, the antibacterial activity of the coatings against Gram-negative Escherichia coli and Gram-positive Staphylocococcus epidermidis was investigated. The coating obtained by co-sputtering of Au, Ag, and Cu exhibited the most pronounced antibacterial properties. This coating was applied to disposable BIC ballpoint pens, which were subsequently used by clients in two public institutions. After three months of regular use, the antibacterial properties of the coatings were re-evaluated. It was confirmed that this coating led to a significant reduction (log5 CFU/mL) in the bacterial presence on the treated surface within 0.5 h. These results support further investigation into the underlying mechanism, which is likely based on the synergistic interaction of the employed noble metal nanoparticles. Full article

The development of efficient photocatalytic materials for waterborne pathogen inactivation and self-cleaning surfaces in biomedical applications remains a critical challenge due to the rising prevalence of antimicrobial-resistant bacteria. This study systematically investigates the structural, optical, and photocatalytic disinfection properties of graphitic carbon nitride (g-C₃N₄) synthesized at variable temperatures (450–600 °C) and doped with transition metals (Mn, Co, Cu). Through FTIR and UV/Vis spectroscopy, we demonstrate that synthesis temperatures between 450 and 550 °C yield a well-ordered polymeric network with enhanced π-conjugation and charge separation, while 600 °C induces structural degradation. Metal doping with Mn and Co significantly enhances photocatalytic disinfection, achieving complete E. coli inactivation (6-log reduction) within 6 h via optimized reactive oxygen species (ROS) generation. The best material (g-C₃N₄ synthesized at 500 °C and doped with Mn) was integrated into sodium alginate hydrogel surfaces, demonstrating reusable self-cleaning functionality with sustained bactericidal activity (5.9-log CFU/mL reduction after five cycles). This work provides a roadmap for tailoring metal-doped g-C₃N₄ composites for practical antimicrobial applications, emphasizing the interplay between synthesis parameters, ROS dynamics, and real-world performance. Full article

Salmonella is one of the main causes of food-borne illness worldwide. In most cases, Salmonella contamination can be traced back to food processing plants and/or to cross-contamination during food preparation. To avoid food-borne diseases, food processing plants use sanitizers and biocidal to reduce bacterial contaminants below acceptable levels. Despite these preventive actions, Salmonella can survive and consequently affect human health. This study investigates the adaptive capacity of the main Salmonella enterica serotypes isolated from the poultry production line, focusing on their replication, antimicrobial resistance, and biofilm formation under stressors such as acidic conditions, oxidative environment, and high osmolarity. Using growth curve analysis, crystal violet staining, and microscopy, we assessed replication, biofilm formation, and antimicrobial resistance under acidic, oxidative, and osmotic stress conditions. Disinfectant tolerance was evaluated by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of sodium hypochlorite. The antibiotic resistance was assessed using the Kirby–Bauer method. The results indicate that, in general, acidic and osmotic stress reduce the growth of Salmonella. However, no significant differences were observed specifically for serotypes Infantis, Heidelberg, and Corvallis. The S. Infantis isolates were the strongest biofilm producers and showed the highest prevalence of multidrug resistance (71%). Interestingly, S. Infantis forming biofilms required up to 8-fold higher concentrations of sodium hypochlorite for eradication. Furthermore, osmotic and oxidative stress significantly induced biofilm production in industrial S. Infantis isolates compared to a reference strain. Understanding how Salmonella responds to industrial stressors is vital for designing strategies to control the proliferation of these highly adapted, multi-resistant pathogens. Full article

Objectives: Burkholderia cepacia complex (Bcc), a Gram-negative organism, is a well-recognized cause of hospital outbreaks, often linked to a contaminated shared source, such as multidose medications. In this study, we report an outbreak of Bcc infections in a tertiary care hospital, associated with the intrinsic contamination of a prepared solution used in interventional radiology (IR) procedures. Additionally, we provide a detailed explanation of the interventions implemented to control and interrupt the outbreak. Methods: Records from the infection control committee from 1 January 2023 to 31 October 2024 were screened to identify cases with Bcc growth in cultured blood, urine, or respiratory samples. Clinical and laboratory data were collected in March 2025. Bacterial identification was performed using conventional methods and MALDI-TOF (Bruker Daltonics, Bremen, Germany). Controls were matched to cases by ward, date of initial growth, and duration of hospitalization. Demographic and clinical data of these patients were systematically collected and analyzed. Microbiological cultures were obtained from environmental objects of concern and certain medications. Results: A total of 82 Burkholderia species were identified. We enrolled 77 cases and 77 matched controls. The source of contamination was identified in ready-to-use intravenous medications (remifentanil and magnesium preparations) in the IR department. These preparations were compounded in advance by the team and were used repeatedly. Although the outbreak originated from contaminated IV medications used in IR, secondary transmission likely affected 28 non-IR patients via fomites, shared environments, and possible lapses in isolation precautions. The mortality rate among the cases was 16.9%. Infection with Bcc was associated with prolonged intensive care unit stays (p = 0.018) and an extended overall hospitalization duration (p < 0.001); however, it was not associated with increased mortality. The enforcement of contact precautions and comprehensive environmental decontamination successfully reduced the incidence of the Bcc outbreak. No pathogens were detected in cultures obtained after the disinfection. Conclusions: The hospital transmission of Bcc is likely driven by cross-contamination, invasive medical procedures, and the administration of contaminated medications. Implementing stringent infection control measures such as staff retraining, updated policies on medication use, enhanced environmental decontamination, and strict adherence to isolation precautions has proven effective in curbing the spread of virulent and transmissible Bcc. Full article

Wastewater is a hotspot for the spread of antimicrobial resistance (AR); therefore, bacteriophages offer a promising biocontrol alternative to overcome the limitations of conventional disinfection. This study evaluated the efficacy of bacteriophages and cocktails for the biocontrol of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) (CG258 and ST307) and Escherichia coli producers of extended-spectrum β-lactamases (ESBL-Ec) (ST131) in simulated wastewater. A synthetic wastewater matrix was prepared in which bacterial viability and bacteriophage stability were assessed for 72 h. CR-Kp or ESBL-Ec strain were treated with individual bacteriophages or phage-cocktails (dosed in different ways) and bacterial loads were monitored for 54 h. The Klebsiella phages FKP3 and FKP14 eliminated 99% (−2.9 Log) of CR-Kp-CG258 at 54 h, and FKP10 reduced 99% (−2.15 Log) of the CR-Kp-ST307 strains. The Klebsiella phage-cocktail in a single dose reduced to 99.99% (−4.12 Log) of the CR-Kp-CG258 at 36 h. Coliphage FEC1 reduced to 2.12 Log (99%) of ESBL-Ec-bla_CTX-M-G9, and FEC2 and FEC4 reduced approximately 1 Log (90%) of ESBL-Ec-bla_CTX-M-G9 and bla_CTX-M-G1. The coliphage cocktail increased the reduction up to 2.2 Logarithms. This study provides evidence supporting the use of bacteriophage cocktails for the control of resistant bacteria in wastewater, a sustainable intervention to mitigate the spread of AR and support water reuse safety. Full article

Background/Objectives: As bacteriophage-based strategies to control bacterial pathogens continue to gain momentum, phage therapy is increasingly being explored across various fields. In the poultry industry, efforts to minimize the public health impact of Salmonella have spurred growing interest in phage applications, particularly as prophylactic and disinfecting agents. Although the disinfecting potential of bacteriophages has been recognized, in-depth studies examining their efficacy under varying environmental conditions remain limited. This study focused on evaluating the effectiveness of bacteriophages as disinfecting agents against biofilm-forming Salmonella Infantis under different environments. Methods: A comprehensive screening of biofilm-producing strains was conducted using Congo Red Agar and 96-well plate assays. Two strains with distinct biofilm-forming capacities were selected for further analysis under different environmental conditions: aerobic and microaerobic atmospheres at both 25 °C and 37 °C. The resulting biofilms were then treated with four phage preparations: three individual phages and one phage cocktail. Biofilm reduction was assessed by measuring optical density and CFU/well. Additionally, scanning electron microscopy was used to visualize both untreated and phage-treated biofilms. Results: The results demonstrated that all S. Infantis strains were capable of forming biofilms (21/21). All three phage candidates exhibited biofilm-disrupting activity and were able to lyse biofilm-embedded Salmonella cells. Notably, the lytic efficacy of the phages varied depending on environmental conditions, highlighting the importance of thorough phage characterization prior to application. Conclusions: These findings underscore that the effectiveness of bacteriophages as surface disinfectants can be significantly compromised if inappropriate phages are used, especially in the presence of biofilms. Full article

As a result of the catalytic decomposition of H₂O₂, hydroxyl radicals are produced. Hydroxyl radicals are strong oxidants and effectively inactivate bacteria, ensuring water disinfection without toxic chlorinated organic by-products. The kinetics of bacterial inactivation were studied in a laboratory-scale flow catalytic reactor. A granular cobalt ferrite catalyst was thoroughly characterized using XRD and XRF techniques, SEM with EDS, and Raman spectroscopy. At lower H₂O₂ concentrations, H₂O₂ decomposition follows first-order reaction kinetics. At higher H₂O₂ concentrations, the obtained kinetics lines suggest that the reaction order increases. The kinetics of bacterial inactivation in the developed flow reactor depends largely on the initial number of bacteria. The initial bacterial concentrations in laboratory tests were within the range typical of real river water. A regression model was developed that relates the degree of bacterial inactivation to the initial number of bacteria, the initial H₂O₂ concentration, and the contact time of water with the catalyst. Full article

Microbial contamination of hatching eggs often leads to reduced hatchability and poor chick quality. As trimethylamine (TMA), a metabolite derived from dietary choline, has antimicrobial properties, increasing yolk TMA contents may increase bacterial resistance to eggs; however, the effects of TMA concentrations on chick quality remain unknown. Hence, this study was conducted to determine the effects of yolk TMA concentrations on the hatchability and chick quality of dwarf hens with different FMO3 genotypes. Hens (n = 140) were divided into control and experimental groups; the latter received choline chloride (2800 mg/kg) to elevate their yolk TMA concentrations. The TMA content, Pasgar score, hatchability, and post-hatching performance were evaluated. The results showed that choline supplementation significantly increased TMA concentrations in hens with AT and TT genotypes. Higher yolk TMA concentrations (≥4 µg/g) correlated with improved Pasgar scores and reduced abnormalities in vitality, navel, and yolk sac absorption. Hatchability peaked at 6.49 µg/g TMA, suggesting a threshold effect. Although the growth rate remained unaffected, chick mortality decreased in the high-TMA group. Therefore, moderate TMA concentrations can enhance egg antimicrobial defenses and improve reproductive performance. This strategy provides a biologically grounded alternative to traditional chemical disinfection in hatcheries. Full article

Microbial contamination of food can lead to faster spoilage and infections. Therefore, disinfection processes are required that have a low detrimental effect on the nutritional content. Concerning radiation disinfection, two spectral ranges have recently become important. The Far-UVC spectral range, with a wavelength below 230 nm and visible violet light. In this study, leaf spinach was used to investigate the extent to which these radiations inactivate Escherichia coli, but also to determine if the vitamin C or chlorophyll content was reduced. Frozen spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO and irradiated with either a 222 nm krypton chloride lamp or 405 nm LEDs. The achieved bacterial reduction was determined by plating the irradiated samples on agar plates and subsequent colony counting. The vitamin C concentration was determined by means of redox titration, and the concentrations of chlorophyll a and chlorophyll b were determined using spectrometry. Both irradiations exhibited a strong antimicrobial impact on E. coli. The average log reduction doses were about 19 mJ/cm² (222 nm) and 87 J/cm² (405 nm), respectively. The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm), and the chlorophyll concentrations decreased by about 25%. Both irradiation approaches are able to substantially reduce microorganisms on spinach leaves by two orders of magnitude, but this is associated with a reduction in the nutrient content. Full article

Background: Hospitalized COVID-19 patients are particularly vulnerable to secondary bacterial infections, which can significantly worsen clinical outcomes. The aim of the study was to identify the cause of bacteremia in a group of hospitalized COVID-19 patients and find out the source of the outbreak to prevent further spread. Methods: Pathogen identification in blood cultures and sensitivity testing were carried out using the automated VITEK2 system. A total of 110 samples were tested; these were collected from patients’ colonization sites and from surfaces, materials and fluids used in the setting. Furthermore, multilocus sequence typing (MLST) and next-generation sequencing (NGS) were employed to characterize the isolates. Results: Achromobacter xylosoxidans was detected in the blood of nine hospitalized patients and in cotton used for disinfection; all isolates presented an identical antibiotic resistance pattern, and all carried the bla_OXA-114 gene which is intrinsic to this species. Infection control measures were implemented promptly. With one exception, all patients recovered and were discharged in good health. Conclusions: This outbreak underscores the urgent need for investigation and control of hospital infections, as bacteremia is associated with increased morbidity, mortality, hospitalization time, and cost. It also highlights the importance of close collaboration among healthcare professionals. Full article

Background: Reusable tourniquets are commonly used to aid venipuncture and blood collection. However, inadequate disinfection may lead to bacterial contamination and increase the risk of healthcare-associated infections (HAIs). Tourniquets can function as fomites, facilitating the spread of pathogenic bacteria. This study assessed microbial contamination of reusable tourniquets in the emergency department and operating theatre, focusing on clinically relevant HAI-associated pathogens. Methods: Tourniquets from four hospital departments (emergency: adult observation and resuscitation; surgical theatres: pediatric and adult general surgery) were sampled at three time points (n = 12). DNA was extracted and analyzed via 16S rRNA sequencing using NGS technology to identify microbial contamination and taxonomic composition. Results: Sequencing revealed 131 bacterial species across the 12 tourniquets, including clinically important pathogens. Among the top ten HAI-associated groups, Klebsiella spp. were detected in 5/12 samples, Enterococcus spp. in 9/12, Staphylococcus aureus in 1/12, Pseudomonas aeruginosa in 9/12, and Acinetobacter spp. in 10/12. No Escherichia coli, Clostridium difficile, coagulase-negative staphylococci, Proteus spp., or Enterobacter spp. were found. Emergency department tourniquets showed higher bacterial loads; operating theatres had greater species diversity. Conclusions: Reusable tourniquets harbor significant bacterial contamination. Considering disinfection challenges and the lack of guidelines, single-use tourniquets should be considered to reduce HAI risk. Full article

Introduction: Successful root canal therapy relies on thorough cleaning and disinfection to eliminate microorganisms and residual pulp tissue. Advanced irrigation activation techniques, including Sonic, Ultrasonic, and Diode Laser activation, have improved cleaning efficacy, bacterial reduction, smear layer removal, and irrigant hydrodynamics. On the other hand, these irrigation activation techniques may lead to a temperature rise that may risk the surrounding periodontal tissue. Thus, this study aimed to investigate the temperature rise during different irrigation activation techniques at various time intervals and evaluate the efficacy of these techniques in removing biofilm-mimicking hydrogel BMH of a simulated root canal system in 3D-printed tooth models. Methods: Ten extracted human mandibular premolars, prepared to size 40/0.04 taper, and a hundred 3D-printed resin premolars with simulated main (0.25 mm) and lateral canals (0.15 mm at 3, 7, 11 mm from apex) were used; 50 of them were filled with biofilm-mimicking hydrogel (BMH). Five irrigation activation techniques were evaluated: Diode Laser, Ultrasonic, Sonic, XP-Finisher, and Control (n = 10). Temperature rises were measured on the extracted premolars after 30 and 60 s of activation using a thermographic camera in a controlled environment (23 ± 2 °C). Irrigant penetration, with and without BMH, was assessed in 3D-printed premolars using a 2.5% sodium hypochlorite-contrast medium mixture, visualized with a CMOS radiographic sensor. Penetration was scored (main canal: 3 points; lateral canals: 0–2 points) and analyzed with non-parametric tests. Results: Diode Laser activation technique resulted in the highest temperature rise on the external root surface, followed by the Ultrasonic, with no statistically significant difference observed among the remaining groups. In terms of efficacy, Ultrasonic and Sonic activation achieved significantly greater irrigant penetration in samples without BMH, and greater BMH removal in samples with BMH, compared to Diode Laser, XP-Finisher, and Control groups. Conclusions: In this in vitro study, Diode Laser caused the highest temperature rise, followed by Ultrasonic, with significant increases from 30 to 60 s. Temperature rise did not significantly affect penetration or BMH removal. Ultrasonic and Sonic irrigation techniques achieved the highest depth of penetration (without BMH) and biofilm-mimicking Hydrogel removal (with BMH) compared to Diode Laser, XP-Finisher, and Control. Full article