Close disease surveillance, environmental awareness are epidemiological keys.
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BACKGROUND: Salmonella enterica encompasses over 2,600 serovars, including several commonly associated with severe infection in humans. Salmonella is a major cause of sepsis in Africa; however, diagnosis requires clinical microbiology facilities. Environmental surveillance has the potential to play a role in Salmonella surveillance. METHODS: We undertook water-based environmental surveillance in Blantyre, Malawi, from 2018-2020, taking samples from rivers (87.9%), a sewage plant (8.85%) and other water sources (3.24%), isolating and storing 1,042 non-typhoidal Salmonella (NTS) isolates in this period. Of these, 341 NTS isolates were whole genome sequenced, genome quality was checked, duplicate genomes from any given sample were removed and core genome phylogeny was reconstructed. AMRFinder, PathogenWatch and SISTR were used to further investigate serovar, sequence type and antimicrobial resistance determinants. RESULTS: After quality checks, and removal of duplicate genomes, 270 NTS genomes remained for further analysis. Multiple Salmonella serovars associated with human infection were detected, of which S. Typhimurium (55/270 isolates) was the most common, including 44 of Sequence Type (ST) 313, a serovar commonly associated with severe invasive disease (iNTS). Six lineage 2 ST313 genomes possessed AMR genes predicting multidrug resistance (MDR), while 29 lineage 3 isolates contained no AMR predictive genes. PCR based detection of staG has been proposed as a diagnostic marker of S. Typhi; however, all eight genomes that contained staG identified as Salmonella enterica serovar Orion, raising concerns about the specificity of this marker as a monoplex for environmental surveillance of S. Typhi. DISCUSSION: The study identified diverse Salmonella serovars in the environment, including those reported to cause invasive disease, emphasizing the complex but potentially valuable contribution of implementing environmental surveillance for Salmonella in high burden areas lacking diagnostic microbiology capacity.
CONTEXT: Environmental surveillance has become an essential component of public health pathogen surveillance programs. Indoor air surveillance is a promising environmental surveillance method but has yet to be scaled citywide and incorporated into state and local public health programs. PROGRAM: The Chicago Department of Public Health established a citywide indoor air surveillance program to enhance monitoring of airborne pathogens and address gaps in existing surveillance. IMPLEMENTATION: The program began with a pilot phase from February to April 2023 at 5 sites, which informed expansion to 17 sites and 20 samplers across emergency departments (5), congregate (3), and community settings (15), across the city. Site staff conducted weekly cartridge exchanges for seven-day sample collection periods using AerosolSense and AirPrep Cub samplers, which were then processed at the Regional Innovative Public Health Laboratory for SARS-CoV-2, influenza, and respiratory syncytial virus. Samples were tested using quantitative polymerase chain reaction, and SARS-CoV-2-positive samples underwent whole genome sequencing to characterize circulating viral lineages. EVALUATION: From February 2023 to August 2025, 1246 samples were processed, with a mean compliance of 85% (SD = 0.149) for weekly cartridge exchanges and minimal operational disruption. The program data supported its use as a surveillance tool for respiratory pathogen detection and SARS-CoV-2 lineage monitoring, with 74% samples positive for at least 1 virus and 68% detecting SARS-CoV-2. DISCUSSION: The program successfully scaled to citywide coverage and was shown to be feasible and acceptable across sites. These results highlight the value of indoor air monitoring as a complementary surveillance tool and offer a framework for other jurisdictions seeking to enhance respiratory pathogen detection through establishing a citywide indoor air surveillance program. Facility-level sampling is aggregated across sites to capture citywide trends complementing clinical and wastewater surveillance, and provides insights into facility-level pathogen burden, not captured by other surveillance methods.
Persistent SARS-CoV-2 transmission, ongoing mpox outbreaks, and the continued spread of endemic diseases such as typhoid fever and cholera underscore the urgent need for global, multiomics surveillance. In this Personal View, we present Project ODIN, a consortium of European and African partners launched in 2023 that aims to meet this challenge by deploying innovative systems for near real-time pathogen detection and actionable public health insights. The project is a collaboration between high-income and low-income countries in northern Europe and sub-Saharan Africa. Focusing on low-income and middle-income countries, ODIN integrates metagenomics with mobile laboratory systems for comprehensive pathogen monitoring across diverse environments. ODIN emphasises standardised sampling, bioinformatics pipelines, and data-sharing protocols to ensure reliable, interoperable results while addressing infrastructure and resource limitations. By bridging gaps in genomic surveillance, these initiatives seek to strengthen outbreak preparedness, improve pathogen detection, monitor antimicrobial resistance, and provide a holistic approach to One Health challenges. Together, these innovations could advance global surveillance capacity-particularly in under-resourced regions-paving the way for effective disease control and evidence-based policy making.
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The Global Specialized Polio Laboratory at CDC supports the Global Poliovirus Laboratory Network with environmental surveillance (ES) to detect the presence of vaccine strain polioviruses, vaccine-derived polioviruses, and wild polioviruses in high-risk countries. Environmental sampling provides valuable supplementary information, particularly in areas with gaps in surveillance of acute flaccid paralysis (AFP) mainly in children less than 15 years. In collaboration with Guatemala's National Health Laboratory (Laboratorio Nacional de Salud Guatemala), monthly sewage collections allowed screening enterovirus (EV) presence without incurring additional costs for sample collection, transport, or concentration. Murine recombinant fibroblast L-cells (L20B) and human rhabdomyosarcoma (RD) cells are used for the isolation of polioviruses following a standard detection algorithm. Though non-polio-Enteroviruses (NPEV) can be isolated, the algorithm is optimized for the detection of polioviruses. To explore if other EV's are present in sewage not found through standard methods, five additional cell lines were piloted in a small-scale experiment, and next-generation sequencing (NGS) was used for the identification of any EV types. Human lung fibroblast cells (HLF) were selected based on their ability to isolate EV-A genus. Sewage concentrates collected between 2020-2021 were isolated in HLF cells and any cytopathic effect positive isolates used for NGS. A large variety of EVs, including echoviruses 1, 3, 6, 7, 11, 13, 18, 19, 25, 29; coxsackievirus A13, B2, and B5, EV-C99, EVB, and polioviruses (Sabin 1 and 3) were identified through genomic typing in NGS. When the EV genotypes were compared by phylogenetic analysis, it showed many EV's were genomically like viruses previously isolated from ES collected in Haiti. Enterovirus occurrence did not follow a seasonality, but more diverse EV types were found in ES collection sites with lower populations. Using the additional cell line in the existing poliovirus ES algorithm may add value by providing data about EV circulation, without additional sample collection or processing. Next-generation sequencing closed gaps in knowledge providing molecular epidemiological information on multiple EV types and full genome sequences of EVs present in wastewater in Guatemala.
The World Health Organization classifies extended-spectrum beta-lactamase (ESBL) and carbapenemase-producing Klebsiella pneumoniae as critical-priority pathogens due to their high incidence, mortality, transmissibility, rapid resistance acquisition, and limited treatment options. Beyond clinical settings, their detection in wastewater treatment plants (WWTPs) provides an opportunity to assess their prevalence, persistence, and circulation within wastewater systems. This study characterized 37 antibiotic-resistant K. pneumoniae-related species strains isolated from two WWTPs in the metropolitan area of Barcelona, analyzing their antimicrobial resistance (AMR) profiles, antimicrobial resistance genes (ARGs), biocide and heavy metal tolerance genes (HMTGs), virulence factor genes (VFGs), biofilm-forming capacity, and conjugation ability. Among them, 70.3% were multidrug-resistant (MDR), and 16.2% were extensively drug-resistant. Whole-genome sequencing revealed diverse ARGs; all strains carried β-lactam resistance genes (14 ESBL and 12 carbapenemase producers), nearly all (96.9%) carried biocide or HMTGs, 64.9% harbored integrases, and all carried VFGs. Core-genome SNP analysis identified closely related strains across sampling periods and treatment stages, suggesting long-term persistence within the wastewater treatment system, despite biological and chemical processes in secondary treatment. Most strains (67.6%) displayed biofilm-forming capacity, and conjugation assays confirmed horizontal gene transfer in five of the seven ESBL-producing strains tested. High-risk clones were predominantly detected in the IFAS secondary treatment stage of the Gavà-Viladecans WWTP. The three strains recovered from the reclaimed water of the Baix Llobregat WWTP were ESBL or carbapenemase producers. Altogether, these results provide genomic and phenotypic evidence of the persistence and circulation of antibiotic-resistant K. pneumoniae-related species within wastewater treatment systems.IMPORTANCEWWTPs are essential for urban sanitation and environmental protection. Understanding how clinically relevant pathogens, such as ESBL and carbapenemase-producing K. pneumoniae-related species strains, behave in these settings may inform public health considerations. Investigating the presence and persistence of high-risk MDR pathogens in WWTPs helps identify circulation of AMR, assess the risk of gene transfer, and evaluate the potential for co-selection with other contaminants. This knowledge supports efforts to improve wastewater treatments, strengthen environmental surveillance, and develop integrated One Health strategies to limit the spread of AMR across human, animal, and environmental sectors.
Sprinkler irrigation systems are critical for modern agriculture but represent largely unrecognized aquatic environments capable of sustaining opportunistic human pathogens. Among them, Legionella pneumophila is of particular concern due to its ability to colonize engineered water systems, persist under fluctuating environmental conditions, and be transmitted through aerosols. In this study, we conducted a comprehensive microbiological and genomic investigation of irrigation ponds and ditches in a rural area of north-east Spain where two zones were sampled. Metagenomic profiling revealed highly diverse microbial communities encompassing more than 20,000 species, including 21 airborne-transmissible bacterial pathogens of clinical relevance. Notably, L. pneumophila was detected in both zones, with a relative abundance of up to 4.6 %. Culture-based isolation confirmed the presence of L. pneumophila serogroup 1, Pontiac group, Benidorm subgroup, sequence type 15. Phylogenetic analysis demonstrated a close relationship between this environmental strain and clinical isolates obtained during a Legionnaires' disease outbreak occurred in 2015, which had remained without a confirmed environmental source. Meteorological data from the exposure period revealed wind conditions favouring long-distance aerosol dispersion from irrigated fields toward residential areas. Our findings provide evidence that irrigation infrastructures can act as environmental reservoirs and dissemination routes of L. pneumophila among other airborne pathogens. These results underscore the need to incorporate agricultural irrigation systems into routine environmental surveillance, outbreak investigations, and public health risk assessments.
Hantaviruses are emerging rodent borne zoonotic pathogens of increasing global public health concern because of their high mortality, expanding ecological distribution, and potential for international dissemination. Although traditionally associated with sporadic rural outbreaks, recent ecological disruption, climate variability, urbanization, and increased global mobility have heightened concerns regarding hantavirus risks in mass gathering settings. This review critically examines the epidemiology, transmission uncertainty, diagnostic and surveillance challenges, and preparedness strategies related to hantavirus infections in the context of mass gatherings, including religious events, refugee settlements, cruise tourism, sporting events, and temporary accommodations. Particular emphasis is placed on the 2026 multinational cruise ship associated outbreak linked to the MV Hondius, which highlighted vulnerabilities related to delayed diagnosis, international passenger dispersal, and uncertainties surrounding possible human to human transmission of Andes virus. Current evidence indicates that hantavirus transmission occurs primarily through inhalation of aerosolized rodent excreta; however, controversies regarding limited interpersonal transmission, environmental persistence, and asymptomatic infections continue to complicate risk assessment and outbreak preparedness. Diagnostic limitations, underreporting, insufficient environmental surveillance, and lack of mass gathering specific preparedness frameworks remain major public health challenges, especially in resource limited settings. Strengthening proactive preparedness through integrated One Health approaches, ecological surveillance, genomic monitoring, AI driven epidemic intelligence, and coordinated international response systems is essential for mitigating future risks. The review emphasizes the urgent need for multidisciplinary research and evidence based policy development to improve global preparedness against emerging hantavirus associated threats in increasingly interconnected mass gathering environments.
OBJECTIVES: To investigate the evolutionary origin, genomic mobility, and potential dissemination of metformin-hydrolysing genes (mfmAB), and to assess whether environmental selection by metformin pollution may drive the emergence of transferable pharmaceutical-degrading traits analogous to antibiotic resistance. METHODS: Large-scale comparative genomics was performed using publicly available bacterial genomes carrying mfmAB homologs. Phylogenomic reconstruction, average nucleotide identity analysis, genomic context comparison, plasmid characterization, and insertion sequence mapping were used to infer evolutionary history and identify mechanisms of horizontal gene transfer. RESULTS: mfmAB homologs were identified in twelve Aminobacter and three Pseudomonas genomes within a conserved ∼8.2 kb gene cluster. Phylogenomic analyses showed that metformin-degrading capacity emerged independently in multiple Aminobacter lineages across distinct continents, consistent with convergent evolution under anthropogenic selective pressure. Genomic comparisons indicated a chromosomal origin of mfmAB, followed by mobilization onto conjugative plasmids through IS1182-mediated transposition. In Pseudomonas, additional IS3/IS6-mediated transposition events integrated mfmAB into diverse plasmid backbones, frequently within composite transposons also encoding guanylurea and biguanide degradation pathways (guuH, bguH). These findings reveal a dynamic modular assembly of metabolic functions facilitating adaptation to pharmaceutical pollutants. CONCLUSIONS: Metformin pollution appears to promote the emergence and mobilization of pharmaceutical-degrading genes through mechanisms paralleling antibiotic resistance evolution. Although no clinical impact has yet been demonstrated, the potential spread of such genes into human-associated microbiomes and their possible co-selection with antibiotic resistance determinants represent an emerging One Health concern. Environmental surveillance of pharmaceutical-degrading genes is warranted to anticipate future threats to drug efficacy.
MOTIVATION: Pangenome graphs are increasingly used in bioinformatics, ranging from environmental surveillance and crop improvement to the construction of population-scale human pangenomes. As these graphs grow in size, methods that scale efficiently become essential. A central task in pangenome analysis is the discovery of variation structures. In directed graphs, the most widely studied such structures, superbubbles, can be identified in linear time. Their canonical generalization to bidirected graphs, ultrabubbles, more accurately models DNA reverse complementarity. However, existing ultrabubble algorithms are quadratic in the worst case. RESULTS: We show that all ultrabubbles in a bidirected graph containing at least one tip or one cutvertex-a common property of pangenome graphs-can be computed in linear time. Our key contribution is a new linear-time orientation algorithm that transforms such a bidirected graph into a directed graph of the same size, in practice. Orientation conflicts are resolved by introducing auxiliary source or sink vertices. We prove that ultrabubbles in the original bidirected graph correspond to weak superbubbles in the resulting directed graph, enabling the use of existing linear-time algorithms. Our approach achieves speedups of up to 25× over the ultrabubble implementation in vg, and of >200× over BubbleGun, enabling scalable pangenome analyses. For example, on the v2.0 pangenome graph constructed by the Human Pangenome Reference Consortium from 232 individuals, after reading the input, our method completes in under 3 min, while vg requires >1 hour, and four times more RAM. AVAILABILITY AND IMPLEMENTATION: Our method is implemented in the BubbleFinder tool github.com/algbio/BubbleFinder, via the new ultrabubbles subcommand.
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Highly pathogenic avian influenza (HPAI) viruses pose an increasing threat to wildlife, livestock and human health, underscoring the need for scalable and early-warning surveillance systems. Environmental RNA (eRNA) monitoring offers a non-invasive, cost-effective alternative to traditional host-based sampling by detecting viral genetic material shed into the environment. Despite its utility, the relative performance of different environmental sampling approaches for avian influenza virus (AIV) detection remains poorly resolved. Here, we conducted a longitudinal study with monthly sampling over approximately one year across two urban waterfowl ponds in Aotearoa New Zealand to evaluate four eRNA sampling strategies - fresh faeces, sediment, active-filtered water and passive-filtered water - for their ability to detect AIV. Using a combination of metagenomic sequencing and RT-qPCR, we show that all sample types can detect AIV, although detections were highly inconsistent across sampling methods, locations and time points. While metagenomic sequencing provided valuable genomic data, including subtype identification and phylogenetic context, RT-qPCR exhibited greater sensitivity, with active-filtered water yielding the highest detection rates, and is currently the more cost-effective approach for large-scale surveillance. Notably, AIV detections were asynchronous among sample types and frequently lacked temporal concordance, suggesting that environmental heterogeneity, RNA persistence, and methodological detection limits strongly influence surveillance outcomes. Despite these inconsistencies, phylogenetic analyses revealed that detected viruses belong to established Australasian lineages, highlighting the ability of environmental surveillance to capture ecologically relevant viral diversity. Our findings demonstrate that while eRNA-based surveillance holds substantial promise as a complementary tool for AIV monitoring, its effectiveness is highly dependent on the environmental sampling strategies and laboratory detection methods used.
Antimicrobial resistance (AMR) is a One Health challenge driven by microbial exchange among humans, animals and the environment. Zoological institutions offer useful settings for environmental AMR surveillance. This single-zoo cross-sectional study examined the occurrence, antimicrobial susceptibility and genomic characteristics of nontyphoidal Salmonella enterica (NTS) and clinically relevant Enterococcus spp. in faecal samples from 101 clinically healthy captive ungulates representing seven conservation-priority species at a major urban zoo in the United Arab Emirates. NTS was detected in 4/101 samples (3.9%), including serovars Schwarzengrund (n = 2), Kentucky (n = 1) and Chester (n = 1). Among the four recovered NTS isolates, all met the study MDR definition within the tested panel, including a Salmonella Kentucky ST198 isolate carrying multiple resistance genes and quinolone-associated mutations. Enterococcus spp. were detected in 77/101 samples (76.2%), dominated by Enterococcus faecium and Enterococcus casseliflavus (each 41.5%). Among 33 E. faecium/Enterococcus faecalis isolates tested phenotypically, resistance was generally low, with erythromycin and ciprofloxacin resistance each observed in 9.1%. One clinically important E. faecium isolate showed glycopeptide resistance and genetic markers associated with reduced daptomycin susceptibility. These single-institution cross-sectional data provide an initial regional baseline for AMR-relevant enteric bacteria in conservation-managed ungulates and identify priorities for broader longitudinal and interface-based surveillance.
One Health concept recognizes the inextricable interactions of diverse ecosystems and their subsequent effect on human, animal and plant health. Antimicrobial resistance (AMR) is a major One Health concern and is predicted to cause catastrophes if appropriate measures are not implemented. To understand the AMR landscape in a south Indian metropolitan city, metagenomic analysis of open drains was performed. The data suggests that in January 2022, macrolide class of antibiotics contributed the highest resistance of 40.1% in the city, followed by aminoglycoside- 24.4%, tetracycline- 11.3% and lincosamide- 6.7%. The 'mutations in the 23S rRNA gene conferring resistance to macrolide antibiotics' were the major contributor of resistance with a prevalence of 39.7%, followed by '16s rRNA with mutation conferring resistance to aminoglycoside antibiotics'- 22.2%, '16S rRNA with mutation conferring resistance to tetracycline derivatives'- 9.2%, and '23S rRNA with mutation conferring resistance to lincosamide antibiotics'- 6.7%. The most prevalent antimicrobial resistance gene (ARG) 'mutations in the 23S rRNA gene conferring resistance to macrolide antibiotics' was present in multiple pathogens including Escherichia coli, Campylobacter jejuni, Acinetobacter baumannii, Streptococcus pneumoniae, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Klebsiella pneumoniae and Helicobacter pylori. Most of the geographical locations in the city showed a similar landscape for AMR. Considering human mobility and anthropogenic activities, such an AMR landscape could be common across other regions too. The data indicates that pathogens are evolving and acquiring antibiotic resistance genes to evade antibiotics of multiple major drug classes in diverse hosts. The outcomes of the study are relevant not only in understanding the resistance landscape at a broader level but are also important for identifying the resistant drug classes, the mechanisms of gaining resistance and for developing new drugs that target specific pathways. This kind of surveillance protocol can be extended to regions in other developing countries to assess and combat the problem of antimicrobial resistance.
Climate change is reshaping the global antibiotic resistance gene (ARG) landscape through geomorphological processes that remain largely overlooked in the One Health framework. This critical review synthesises evidence on how soil erosion and landscape elevation gradients redistribute, select for, and disseminate ARGs across terrestrial and aquatic ecosystems. Erosion physically removes and transports ARG-bearing microbes, depletes nutrients, and co-selects for resistance via heavy metal exposure and horizontal gene transfer, creating source-sink dynamics that connect eroding hillslopes to downstream water bodies and food systems. Elevation gradients impose abiotic stressors-declining temperature, elevated UV radiation, and shifting pH-that drive microbial community reassembly through environmental selection and dispersal limitation, with emerging evidence linking bacterial competition at high altitude to enhanced multidrug efflux and resistome complexity. The review identifies critical knowledge gaps, including unquantified ARG mass fluxes across erosion-deposition gradients, unresolved dispersal-versus-selection mechanisms along elevation transects, and the absence of integrated One Health surveillance linking environmental ARG reservoirs to clinical outcomes. A synthesis of global case studies illustrates how these processes converge across diverse landscapes. The review concludes with a mechanistic research agenda-including reciprocal transplant experiments, landscape connectivity modelling, and cross-sectoral surveillance-needed to translate these emerging drivers into actionable climate-AMR mitigation policy.