Water quality is under threat due to the presence of pathogenic and antibiotic-resistant bacteria. Escherichia coli (E. coli) serves as an indicator of faecal contamination and the potential presence of other harmful pathogens. Understanding E. coli concentrations helps in assessing the overall health risks associated with waterborne diseases and developing effective water management strategies. Therefore, we developed the first large-scale model, GloWPa-Ecoli C1 to simulate E. coli loads and concentrations in rivers and apply this model to China. The model provides the first comprehensive overview of microbial water quality across China's rivers. The model simulates E. coli concentrations in 2020 to range from 10−1.2 to 106.3 CFU/L, with 45.6 %–78.1 % of rivers exhibiting poor microbial water quality. Major hotspots of E. coli pollution are Haihe, Huaihe and Pearl River Basins. Direct discharge of human faecal waste contributes 80.2 % of the total E. coli load, while directly discharged livestock waste accounts for 13.1 %. To mitigate E. coli pollution in rivers in China, we recommend increasing human faecal waste collection rates, expanding wastewater treatment plant (WWTP) coverage, phasing out primary treatment WWTPs and eliminating direct livestock faecal waste discharge, particularly from smallholder farms. The study underscores the urgent need to improve microbial water quality in China's rivers. The findings provide actionable insights to inform policy development aimed at safeguarding water quality and public health. Furthermore, the modelling approach is applicable to other regions and microorganisms, offering a foundation for developing models to address antibiotic-resistant bacteria and other emerging water quality challenges.@en

Background/Objectives: The global spread of carbapenem-resistant Pseudomonas aeruginosa (CRPA) warrants collaborative action. Guidance should come from integrated One Health surveillance; however, a surveillance strategy is currently unavailable due to insufficient knowledge on the sources and transmission routes of CRPA. The aim of the SAMPAN study (“A Smart Surveillance Strategy for Carbapenem-resistant Pseudomonas aeruginosa”) is to develop a globally applicable surveillance strategy. Methods: First, an international cross-sectional study will be conducted to investigate CRPA in clinical and environmental settings in Rotterdam (The Netherlands), Rome (Italy), and Jakarta (Indonesia). Screening cultures and risk factor questionnaires will be taken from healthy individuals and patients upon hospital admission. Clinical CRPA isolates will also be included. Additionally, samples will be taken twice from wet hospital environments and monthly from the hospitals’ (drinking) water system, hospital and municipal wastewater treatment plants, and receiving rivers. Whole-genome sequencing will be performed to characterize CRPA isolates and determine the genetic relatedness among the isolates from different reservoirs. Findings from the cross-sectional study, combined with expert elicitation using a Delphi method, will serve as the input for the surveillance strategy. Conclusions: The SAMPAN study will provide a broader understanding of the sources and transmission routes of CRPA. Therewith, the development of a globally applicable smart surveillance strategy will be made possible, delivering information that is needed to guide actions against the spread of CRPA.

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Water systems can act as an important reservoir for Pseudomonas aeruginosa, which can pose public health risks during human contact. Carbapenem resistance is one of the most concerning resistances in P. aeruginosa making it a high-priority pathogen according to the World Health Organization (WHO), due to its ability to cause difficult-to-treat infections. Culture methods for detecting carbapenem-resistant P. aeruginosa (CRPA) have generally been developed for clinical samples but rarely for water. Therefore, the aim of this study was to develop a standardized and widely applicable method for detecting CRPA in water samples, both in surface water and wastewater. Growth of well-characterized strains of CRPA was determined in four different selective agar media which were each supplemented with imipenem, meropenem, or ceftazidime, including after an enrichment. Wastewater samples presumptively containing CRPA (naturally contaminated samples) and surface water samples spiked with well-characterized CRPA strains were filtered and cultured using selective agar plates supplemented with imipenem and meropenem, with and without a prior enrichment step. M-PA-C agar plates supplemented with imipenem performed best compared to other selective agar plates with respect to growth of well-characterized CRPA strains and suppression of background growth of other bacteria and carbapenem-susceptible P. aeruginosa (CSPA) with positive predictive value of 80–100 %. A prior step using asparagine proline broth with vancomycin is recommended for higher specificity considering direct plating was unsuccessful due to extensive background growth. A combination of nonselective enrichment with selective plating (i.e., addition of imipenem to the plate) is recommended to achieve low limits of detection. The addition of imipenem in the broth instead of in solid agar plates eliminated some of the CRPA strains, producing an increase in the lower limit of detection and a lower PPV (32 % vs 73 %).@en

Antimicrobial resistance (AMR) is among the top 10 public health threats, with nearly 5 million deaths in 2019 linked to AMR-related bacterial infections. (1) A One Health approach is needed to combat AMR.

Healthcare-based surveillance (HBS) of AMR provides incomplete information about the scope of the AMR threat. HBS screens only patients seeking medical attention, lacking community-level representativeness, and suffers from underreporting. (2) Consequently, researchers are turning to wastewater-based surveillance (WBS) to complement HBS. (3) WBS can provide information about AMR circulating within communities and hospitals, offering a comprehensive understanding of AMR prevalence. However, the surveillance targets and data obtained from WBS are distinct from those derived from HBS, creating uncertainty regarding their utility to the public health sector and ability to yield policy relevant information. In May 2024, participants in a workshop during the 7th Environmental Dimension of Antimicrobial Resistance (EDAR7) conference (Montréal, Canada) sought to answer four questions aimed at advancing the policy relevance of AMR data generated by WBS.@en

Each year, an estimated 7·7 million deaths are attributed to bacterial infections, of which 4.95 million are associated with drug-resistant pathogens, and 1·27 million are caused by bacterial pathogens resistant to the antibiotics available. Access to effective antibiotics when indicated prolongs life, reduces disability, reduces health-care expenses, and enables access to other life-saving medical innovations. Antimicrobial resistance undoes these benefits and is a major barrier to attainment of the Sustainable Development Goals, including targets for newborn survival, progress on healthy ageing, and alleviation of poverty. Adverse consequences from antimicrobial resistance are seen across the human life course in both health-care-associated and community-associated infections, as well as in animals and the food chain. The small set of effective antibiotics has narrowed, especially in resource-poor settings, and people who are very young, very old, and severely ill are particularly susceptible to resistant infections. This paper, the first in a Series on the challenge of antimicrobial resistance, considers the global scope of the problem and how it should be measured. Robust and actionable data are needed to drive changes and inform effective interventions to contain resistance. Surveillance must cover all geographical regions, minimise biases towards hospital-derived data, and include non-human niches.

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Aerobic granular sludge (AGS) is gaining popularity as an alternative to activated sludge for wastewater treatment. However, little information is available on AGS regarding the removal of organic micropollutants (OMPs) through sorption. In this study, the sorption behavior of 24 OMPs at environmentally relevant concentrations (1 μg/L) was investigated in six sludge fractions of varying sizes (>4 mm, 2–4 mm, 1–2 mm, 0.6–1 mm, 0.2–0.6 mm, and <0.2 mm) from a full-scale AGS reactor using batch experiments. Sorption was significant (removal efficiency >40 %) for 10 OMPs, including 4 zwitterionic and 6 positively charged pharmaceuticals, indicating the importance of electrostatic interaction for OMP sorption in AGS systems. Larger granules exhibited a higher sorption coefficient and capacity than smaller AGS fractions, probably due to increased extracellular polymeric substance content for larger granules. Equilibrium OMP sorption was only reached after 72 h in granules larger than 2 mm, indicating an effect of longer diffusion distance for OMPs into larger granules. Additionally, compared to activated sludge, AGS demonstrates a similar or even slightly higher sorption capacity for 10 OMPs at 1 μg/L. Overall, this study is the first to investigate the sorption behavior of six AGS size fractions for OMPs at environmentally relevant concentrations (1 μg/L) and propose the possible roles of different-sized sludge in OMP sorption in the full-scale AGS reactor.@en

Surveillance of antibiotic resistance genes (ARGs) has been increasingly conducted in environmental sectors to complement the surveys in human and animal sectors under the "One-Health"framework. However, there are substantial challenges in comparing and synthesizing the results of multiple studies that employ different test methods and approaches in bioinformatic analysis. In this article, we consider the commonly used quantification units (ARG copy per cell, ARG copy per genome, ARG density, ARG copy per 16S rRNA gene, RPKM, coverage, PPM, etc.) for profiling ARGs and suggest a universal unit (ARG copy per cell) for reporting such biological measurements of samples and improving the comparability of different surveillance efforts.

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Source-separated gray water reclamation using nanofiltration as an advanced post-treatment option has received substantial interest in meeting the growing water demand. During reclamation, membrane integrity is crucial to ensure the water’s safety. This study evaluated several chemical and novel microbial indicators as indirect membrane integrity-monitoring methods for hollow fiber nanofiltration membranes in reclamation schemes. Under normal conditions, high retention of divalent ions and organic matter and near-complete removal of Escherichia coli (E. coli) were observed. Limited removal of the antibiotic gene (ARG) tetO was observed due to low feed concentrations and a higher detection limit (LOD). While 16S rRNA and ARG sul1 were not limited by their LODs, lower removals were observed, most likely due to free-floating DNA passing through the membranes. A broken fiber in a pilot-scale module reduced organic matter and microorganism removal substantially, while flux and ion rejection remained similar. Predictions made using the observed results and a previously proposed model allowed for the evaluation of the selected methods in upscaled reclamation systems. Based on these results, it was concluded that microorganisms could be employed as indicators in indirect membrane integrity-monitoring methods in large-scale reclamation schemes, while UV_254nm absorbance (used in organic matter determination) could be a viable solution in pilot-scale systems.

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