Urban Wastewater Metagenomics Reveals the Antibiotic Resistance Gene Distribution Across Latvian Municipalities Edgars Liepa, Maija Ustinova, Dita Gudra, Ance Roga, Ineta Kalnina, Brigita Dejus, Sandis Dejus, Martins Strods, Laura Elīna Tomsone, Juris Kibilds, Vadims Bartkevics, Aivars Berzins, Uga Dumpis, Talis Juhna, Davids Fridmanis Microorganisms, 2026 Antimicrobial resistance (AMR) poses a global health threat, with urban wastewater systems serving as key reservoirs for resistance dissemination. This study aimed to investigate the relationships among urban environments, bacterial communities, and AMR patterns, and evaluate the specific municipal-scale drivers of resistance gene distribution. Shotgun metagenomic analysis was conducted on 45 wastewater samples collected from 15 municipalities across Latvia to determine the composition of the resistome and its correlation with local factors. The analysis identified 417 distinct antibiotic resistance genes (ARGs) belonging to 108 families, with geographic location serving as the primary driver of ARG distribution, which explained 65.87% of community variation (p = 0.001). Local industrial factors demonstrated significant effects, with food industry wastewater significantly influencing both bacterial taxonomy and ARG profiles (p < 0.05). While the presence of a regional hospital did not shape the overall municipal resistome, hospital-associated wastewater showed 19 overlapping ARGs, including clinically critical carbapenemases. Municipal wastewater systems function as geographically structured reservoirs of AMR that are shaped by localized industrial and healthcare outputs. These findings support wastewater-based AMR surveillance as a valuable tool for tracking specific resistance sources.
Examining the impact of different scales on COVID-19 monitoring in sewerage catchment areas: Insights from Latvia Brigita Dejus, Dita Gudra, Sandis Dejus, Roberts Ozols, Juris Laicans, Martins Strods, Davids Fridmanis, Maija Ustinova, Ance Roga, Janis Grabis, Vineta Minkevica, Talis Juhna Journal of Hazardous Materials Advances, 2025 • Explores COVID-19 monitoring trends across multiple wastewater levels, including the use of metagenomics. • Identifies consistent COVID-19 patterns across catchment levels, mapping virus spread. • Highlights gut microbiome monitoring as a potential early COVID-19 warning tool. The spread and transmission of coronavirus, SARS-CoV-2, have become a significant global concern. As the SARS-CoV-2 virus can be released into the environment through various human excretions, it provides a possibility for early detection and identification within a population through the use of wastewater-based epidemiology (WBE). With the rapid progress in the application of WBE during the COVID-19 pandemic, researchers have been able to provide evidence of SARS-CoV-2 shedding in wastewater and aid in decision-making for public health measures. However, there is a lack of research on potential trends and correlations between different levels of wastewater sample analysis, from building-level to municipality-level. Therefore, this study aims to fill this gap and also explore the use of metagenomic analysis in addition to the amount of viral RNA concentration in wastewater samples for COVID-19 monitoring at different levels. Results from monitoring indicated consistent patterns of COVID-19 and variants at the building, community, and municipality levels. However, there was a statistical difference in transmission dynamics at the building level during the spring season, possibly due to localized factors. Thus, the comparison of monitoring data from COVID-19 across different sewage catchment areas plays a crucial role in understanding the geographical spread of COVID-19. Metagenome analysis revealed a predominance of gut-associated microbes in wastewater, but no significant seasonal variations were observed. Further research is necessary to fully understand the relationship between changes in the gut microbiome and the distribution of COVID-19.
Effect of UVA/UVC-activated TiO2 coating on sinks' pipeline system to control biofilm at ICU: A case study from Latvia Brigita Dejus, Martins Strods, Basanti Ekka, Liva Kairisa, Kristens Rascevskis, Peteris Sala, Inese Jansone, Davids Fridmanis, Dita Gudra, Talis Juhna, Uga Dumpis Journal of Water Process Engineering, 2025 Preventing infections caused by antimicrobial-resistant (AMR) pathogens is critical in healthcare settings, particularly in ICUs , where patients are highly susceptible to infections. Sink and pipeline systems display the potential to be the cause of point source outbreaks in intensive care units (ICUs). Here, we performed lab- and real-life experiments to investigate using TiO 2 coating on the inner side of a U-shaped wastewater pipe as the reducer of clinically relevant multidrug-resistant (MDR) microorganisms. During the lab-scale experiments, we evaluated the efficacy of the TiO 2 coating in combination with UVA/UVC light against both Gram(+) and Gram(−) bacterial strains commonly found in ICUs . At the same time, in the pilot experiments that were carried out in a real-life ICU setting, we monitored the changes in the diversity of the microbiological community within a sink that was equipped with the combination of TiO 2 coating and UVA/UVC light source . The lab-scale results showed that TiO 2 coating alone did not have an additional effect on bacteria reduction based on incubation time , power level, and usage time, while the pilot scale demonstrated that TiO 2 coating combination with UVA/UVC light effectively reduced the microbial diversity in the pipeline system of the ICU sink. Overall, this study combines experiments in the laboratory and real-life ICU settings to investigate the effectiveness of a TiO 2 coating and UVA/UVC light combination for eliminating MDR microorganisms, thus providing valuable knowledge that will aid the development of future infection control strategies. Additionally, this study emphasizes the importance of continuous maintenance and monitoring in preventing the growth of MDR bacteria .
Precision and Accuracy Limits of Wastewater-Based Epidemiology—Lessons Learned from SARS-CoV-2: A Scoping Review Juris Laicans, Brigita Dejus, Sandis Dejus, Talis Juhna Water Switzerland, 2024 Background: Wastewater-based epidemiology (WBE) has become crucial for early microbial outbreak detection and public health surveillance globally, underscored by the COVID-19 pandemic. However, despite advancements in sampling and analyses, interpreting results and estimating infection rates pose challenges. Enhancements in sewer system engineering, understanding the wastewater environment, and addressing the impact of the environment on the accuracy of results are needed. Objective: This scoping review aims to identify engineering knowledge gaps in WBE to guide future study designs. Design: Research on “wastewater-based epidemiology” involving “engineering”, published between 2015 and 2023, was extracted from the Scopus database. Results: This scoping review examines elements influencing WBE’s precision and reliability, especially in identifying and measuring SARS-CoV-2 RNA. It identifies significant effects of engineering, analytical practices, and the wastewater’s composition on WBE performance. Conclusions: This review calls for further investigation into economical evaluation methods of these factors to enhance WBE data normalization and interpretation, utilizing existing wastewater treatment plant data used for treatment control, which could be a cost-effective approach over more expensive population biomarkers. This approach, aside from SARS-CoV-2, holds potential for application to a broader number and types of diseases, as well as population consumption habits.
Photocatalytic Activity of TiO2 Coatings Obtained at Room Temperature on a Polymethyl Methacrylate Substrate Mairis Iesalnieks, Raivis Eglītis, Tālis Juhna, Krišjānis Šmits, Andris Šutka International Journal of Molecular Sciences, 2022 Titanium dioxide (TiO2) coatings have a wide range of applications. Anatase exhibits hydrophilic, antimicrobial, and photocatalytic properties for the degradation of organic pollutants or water splitting. The main challenge is to obtain durable anatase nanoparticle coatings on plastic substrates by using straightforward approaches. In the present study, we revealed the preparation of a transparent TiO2 coating on polymethylmethacrylate (PMMA), widely used for organic optical fibres as well as other polymer substrates such as polypropylene (PP), polystyrene (PS), and polycarbonate (PC). The films were spin-coated at room temperature without annealing; therefore, our approach can be used for thermo-sensitive substrates. The deposition was successful due to the use of stripped ultra-small (<4 nm) TiO2 particles. Coatings were studied for the photocatalytic degradation of organic pollutants such as MB, methyl orange (MO), and rhodamine B (RB) under UV light. The TiO2 coating on PMMA degraded over 80% of RB in 300 min under a 365 nm, 100 W mercury lamp, showing a degradation rate constant of 6 × 10−3 min−1. The coatings were stable and showed no significant decrease in degradation activity even after five cycles.
Affordable Pretreatment Strategy for Mitigation of Biofouling in Drinking-Water Systems Marta Zemite, Linda Mezule, Kamila Gruskevica, Kristina Kokina, Janis Rubulis, Talis Juhna, Nathalie Gottschalk, Franca Dömer, René Jagau, Katharina Röwe, Wolfgang Augustin, Stephan Scholl, Ana Pereira, Ana C. Barros, Idalina Machado, Luis F. Melo Journal of Environmental Engineering United States, 2022
Rapid Catalytic Water Disinfection from Earth Abundant Ca2Fe2O5 Brownmillerite Mārtiņš Vanags, Linda Mežule, Arnita Spule, Juris Kostjukovs, Krišjānis Šmits, Aile Tamm, Talis Juhna, Svetlana Vihodceva, Tanel Käämbre, Larisa Baumane, Dzintars Začs, Grigory Vasiliev, Maris Turks, Inese Mierina, Peter C. Sherrell, Andris Šutka Advanced Sustainable Systems, 2021
Vertically integrated projects (VIP) programs at international institutions: Multidisciplinary projects with homes in any discipline 2017 ASEE International Forum, 2017
Application of FT-IR for characterization of biomass isolated from surface and drinking water with high concentration of natural organic matter 8th International Conference on Environmental Engineering Icee 2011, 2011
Chemical and microbial composition of loose deposits in drinking water distribution systems 7th International Conference on Environmental Engineering Icee 2008 Conference Proceedings, 2008
Simulation of bacterial regrowth in water networks by modelling of Pseudomonas fluorescens growth in a batch and lab biofilm reactor Proceedings of the Combined International Conference of Computing and Control for the Water Industry Ccwi2007 and Sustainable Urban Water Management Suwm2007, 2007
