Environmental Reservoirs Research Articles

Genetically modified indigenous Pseudomonas aeruginosa drove bacterial community to change positively toward microbial enhanced oil recovery applications.

Microbial enhanced oil recovery (MEOR) is cost-effective and eco-friendly for oil exploitation. Genetically modified biosurfactants-producing high-yield strains are promising for ex-situ MEOR. However, can they survive and produce biosurfactants in petroleum reservoirs for in-situ MEOR? What is their effect on the native bacterial community? A genetically modified indigenous biosurfactants-producing strain Pseudomonas aeruginosa PrhlAB was bioaugmented in simulated reservoir environments. Pseudomonas aeruginosa PrhlAB could stably colonize in simulated reservoirs. Biosurfactants (200mg l-1) were produced in simulated reservoirs after bio-augmenting strain PrhlAB. The surface tension of fluid was reduced to 32.1 mN m-1. Crude oil was emulsified with an emulsification index of 60.1%. Bio-augmenting strain PrhlAB stimulated the MEOR-related microbial activities. Hydrocarbon-degrading bacteria and biosurfactants-producing bacteria were activated, while the hydrogen sulfide-producing bacteria were inhibited. Bio-augmenting P. aeruginosa PrhlAB reduced the diversity of bacterial community, and gradually simplified the species composition. Bacteria with oil displacement potential became dominant genera, such as Shewanella, Pseudomonas, and Arcobacter. Culture-based and sequence-based analyses reveal that genetically modified biosurfactants-producing strain P. aeruginosa PrhlAB are promising for in-situ MEOR as well.

Potential application of wet-phase modified expandable graphite particles as a novel in-depth profile control agent in carbonate reservoirs

Novel wet-phase modified expandable graphite (WMEG) particles were developed for in-depth profile control in carbonate reservoirs. The harsh environment of carbonate reservoirs (≥ 130 °C, ≥ 22 × 104 mg/L) brings significant challenges for existing profile control agents. WMEG particles were developed to address this problem. WMEG particles were synthesized via intercalation with ultrasound irradiation and chemical oxidation. The critical expansion temperature of WMEG particles is 130 °C, and these particles can effectively expand 3–8 times under high temperature and high salinity water. The core flow experiments show that WMEG particles exhibit a good plugging capacity, profile control capacity, and a better-enhanced oil recovery (EOR) capacity in deep carbonate reservoirs. WMEG particles can be expanded in the formation and form larger particles that bridge the upper and lower end faces of the fracture. Then the high-permeability zones are effectively plugged, and the heterogeneity is improved, resulting in an obvious increase in oil recovery. This research provides a novel insight into future applications of profile control agents for in-depth profile control treatment in carbonate reservoirs.

Capturing MRSA Diversity by Integrating Genomic and Epidemiological Data of Patients and their Spaces

Background: Methicillin-resistant S. aureus (MRSA) is known to cause frequent and severe infections in community living centers, potentially resulting in significant mortality for elderly patients. More research is needed to understand how to utilize genomic and epidemiological data to understand characteristics that may lead to increased transmission. We hypothesized that combining genomic and epidemiological information to sample patients and their environments during long-term stays, we will be able to capture a diverse set of MRSA strains. Method: This work included genome sequencing of patient and environmental samples from 11 patients within the VA Ann Arbor Healthcare System from May 4, 2021- November 16, 2022. All 11 patients tested positive for MRSA during their stay (mean days = 31). Patient and environmental samples were taken throughout their stays, screened for MRSA, and whole-genome sequenced. Single nucleotide variants (SNVs) were identified by mapping reads and calling variants against strain-specific reference genomes. We used ape v5.6-2 in R v4.2.2 to analyze and infer evolution, acquisition, and transmission events based on pairwise SNV distances. Genomic clusters were determined using stats v3.6.2, with a SNV distance threshold of 20. Result: Samples that were collected from patient bodily sites were able to reveal 20 distinct genomic clusters of MRSA (patient hands: n = 10, nares: n = 7, groin: n = 3). Environmental samples from patient environments also revealed distinct genomic MRSA clusters (tv remote: n = 9, toilet seat and bed rail: n = 6, table top, bed control, and call button: n = 5, bed curtain: n = 4, pulse ox = 2, cell phone, tray, pulse ox, mat, body hoist wrap, and bed: n = 1). Conclusion: The identification of various genomic clusters from patients and their environmental reservoirs suggests intrahost variation that can only be captured by using a more holistic approach of integrating epidemiology and genomic sequencing. Developing studies that incorporate genomic data, various environmental sources, and multiple isolates over time within community living centers can increase our understanding of strains that are more likely to transmit, survive on living and non-living surfaces and therefore lead to improved recommendation for infection prevention interventions and drivers of endemicity.Disclosure: Lona Mody: NIH, VA, CDC, Kahn Foundation; Honoraria: UpToDate; Contracted Research: Nano-Vibronix

Centimetre scale functional dispersal limitation of freshwater copiotrophs.

The freshwater microbiome harbours numerous copiotrophic bacteria that rapidly respond to elevated substrate concentrations. We hypothesized that their high centimetre-scale beta diversity in lake water translates into pronounced metabolic variability, and that a large fraction of microbial 'metabolic potential' originates from point sources such as fragile organic aggregates. Three experiments were conducted in pre-alpine Lake Zurich over the course of a harmful cyanobacterial bloom: Spatially explicit 9 ml 'syringe' samples were collected in situ at centimetre distances along with equally sized 'mixed' samples drawn from pre-homogenized lake water and incubated in BIOLOG EcoPlate substrate arrays. Fewer compounds promoted bacterial growth in the syringe than in the mixed samples, in particular during the pre- and late bloom periods. Community analysis of enrichments on three frequently utilized substrates revealed both pronounced heterogeneity and functional redundancy. Bacterial consortia had higher richness in mixed than in syringe samples and differed in composition. Members of the Enterobacter cloacae complex dominated the EcoPlate assemblages during the mid-bloom period irrespective of treatment or substrate. We conclude that small-scale functional dispersal limitation among free-living copiotrophs in lake water reduces local biotransformation potential, and that lacustrine blooms of harmful cyanobacteria can be environmental reservoirs for metabolically versatile potential pathogens.

Resetting the environmental reservoir; evaluating the impact of a new hospital building on Clostridioides difficile infection

Background: Prior research has implicated contaminated surfaces in the transmission of Clostridioides difficile within the hospital. To reduce the risk of transmission, enhanced environmental hygiene is performed in rooms of patients with known C.difficile infection (CDI). We wished to evaluate the residual impact of environmental surfaces on hospital-onset CDI (HO-CDI) by comparing HO-CDI rates before and after the opening of a new 504-bed hospital building, HUP Pavilion (PAV). We hypothesized that we would observe a reduction in HO-CDI after opening of PAV due to a reduced burden of C.difficile spores in the environment. Methods: We included NHSN reported HO-CDI rates for 28 months prior and 24 months after opening of PAV. Upon opening, patients were divided between the old building (HUP) and PAV. We included all patient units before and after opening. We created hierarchical models of HO-CDI rates using Stan Hamiltonian Monte Carlo (HMC) version 2.30.1, via the “cmdstanr” and “brms” packages with a GAM smooth function by month and intervention period with default, weakly-informative priors. Results: At baseline, there was an average of approximately 20,100 patient days per month, subsequently divided between HUP and PAV (mean 10,100 and 12,100 patient days per month). After opening of PAV, we observed a reduced HO-CDI rate (mean 0.21 vs 0.31 per 1000 patient days, P=0.01). When comparing the two specific buildings after opening of PAV, there was a greater reduction noticed in the old building (HUP) as compared to the new building (PAV) (0.12 vs 0.29 per 1000 patient days) (Figure 1). The predicted contrast in HO-CDI rate (Figure 2), shows no immediate change in HO-CDI after opening, however a sustained reduction estimated at 0.1 HO-CDI events per 1000 patient days for the duration of follow-up. Conclusions: We observed a reduction in HO-CDI rates after the opening of a new hospital building. The difference in HO-CDI rates between hospital buildings after the move is likely due to the concentration of high-risk patient cohorts within this building. Our findings suggests that there remains an opportunity to reduce HO-CDI through environmental hygiene. However, it is possible that other factors beyond surface environment contributed to an observed reduction in HO-CDI, including other concurrent infection control interventions that focused on smaller populations within the hospital. In future work we will investigate the durability of this observed effect with additional analyses including patient-level risk for HO-CDI.

Containment of a KPC-CRE Outbreak Associated with Premise Plumbing in a Long-Term Care Facility— Minnesota, 2022-2023

Background: On March 23, 2022, the Minnesota Department of Health (MDH) was notified of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella oxytoca isolated from a resident’s urine in long-term care facility A (LTCF-A). Carbapenem-resistant Enterobacterales (CRE) are reportable statewide with required isolate submission to MDH Public Health Laboratory (MDH-PHL), where carbapenemase production and mechanism identification is confirmed. Methods: MDH partnered with LTCF-A on a containment response, including infection prevention and control (IPC) measures, KPC-CRE education, and colonization screening. Rectal swabs were screened for carbapenemase genes by real-time PCR (Cepheid Xpert Carba-R), with positive specimens undergoing culture, isolation, and whole genome sequencing (WGS). MDH-PHL conducted WGS including multilocus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis to describe genetic relationships among isolates. When screening indicated a potential environmental source, due to species diversity and ongoing resident transmission, an environmental screening plan was developed including collection of premise plumbing samples from room faucets, aerators, sinks, toilets, and shared shower drains. Results: KPC-CRE was detected in 23 residents (urine, n=2; rectal swab, n=21) during March 2022–November 2023. 21 isolates comprising 10 Enterobacterales species were cultured from KPC-positive screening specimens. SNP analysis performed on bacteria of the same species demonstrated 5 distinct clusters of relatedness comprising 2-3 residents per cluster (Cluster 1: Klebsiella oxytoca, n=3; Cluster 2: Klebsiella oxytoca, n=3; Cluster 3: Escherichia coli, n=2; Cluster 4: Klebsiella pneumoniae, n=2; Cluster 5: Raoultella planticola, n=2). 7 KPC-positive resident specimens did not yield a culturable organism. KPC-CRE was detected throughout the premise plumbing including 8 of 9 shared shower room drains and 6 of 75 resident room sink drains. WGS and SNP analysis suggest relatedness among resident and environmental KPC-CRE isolates. Gaps in IPC measures including hand hygiene, use of personal protective equipment (PPE), environmental cleaning and disinfection, and sink hygiene practices were observed during onsite assessments. Use of an EPA-registered biofilm disinfectant in facility drains and repeated environmental sampling has demonstrated a decrease in KPC-harboring bacteria within the premise plumbing, but not complete elimination. Conclusion: Containing the spread of KPC-CRE within LTCF-A has been challenging due to environmental reservoirs of KPC-CRE along with insufficient implementation of IPC practices. Continued colonization screening has been necessary to detect newly colonized residents and reinforce efforts to increase IPC compliance. Strict implementation and adherence to IPC measures, including those that minimize the spread of KPC-CRE from facility premise plumbing, are needed to fully halt KPC-CRE transmission within LTCF-A.

Utilizing whole genome sequencing to characterize Listeria spp. persistence and transmission patterns in a farmstead dairy processing facility and its associated farm environment

Farmstead dairy processing facilities may be particularly susceptible to Listeria spp. contamination due to the close physical proximity of their processing environments (PE) to associated dairy farm environments (FE). In this case study, we supported the implementation of interventions focused on improving (i) cleaning and sanitation efficacy, (ii) hygienic zoning, and (iii) sanitary equipment/facility design and maintenance in a farmstead dairy processing facility, and evaluated their impact on Listeria spp. detection in the farmstead's PE over 1 year. Detection of Listeria spp. in the farmstead's PE was numerically reduced from 50% to 7.5% after 1 year of intervention implementation, suggesting that these interventions were effective at improving Listeria spp. control. In addition, environmental samples were also collected from the farmstead's FE to evaluate the risk of the FE as a potential source of Listeria spp. in the PE. Overall, detection of Listeria spp. was higher in samples collected from the FE (75%, 27/36) compared with samples collected from the PE (24%, 29/120). Whole genome sequencing (WGS) performed on select isolates collected from the PE and FE supported the identification of 6 clusters (range of 3 to 15 isolates per cluster) that showed ≤ 50 high quality single nucleotide polymorphism (hqSNP) differences. Of these 6 clusters, 3 (i.e., clusters 2, 4, and 5) contained isolates that were collected from both the PE and FE, suggesting that transmission between these 2 environments was likely. Moreover, all cluster 2 isolates represented a clonal complex (CC) of L. monocytogenes commonly associated with dairy farm environmental reservoirs (i.e., CC666), which may support that the farmstead's FE represented an upstream source of the cluster 2 isolates that were found in the PE. Overall, our data underscore that, while the FE can represent a potential upstream source of Listeria spp. contamination in a farmstead dairy processing facility, implementation of targeted interventions can help effectively minimize Listeria spp. contamination in the PE.

Microbial Carriage of Shuttle Door Handles and Campus Bank’s Automated Teller Machines

Microorganisms are ubiquitous organisms that can cause microbial contamination in both indoor and outdoor settings, with frequently touched surfaces acting as environmental reservoirs that increase the ability of pathogens to be transferred from host to host. This study was aimed at isolating, identifying and characterizing bacteria and fungi present on frequently used Automated Teller Machines (ATMs) and campus shuttle bus handles at Adekunle Ajasin University, Akungba-Akoko, Ondo State. Swab samples were obtained from the keypads of ATMs and door handles of campus shuttle buses. Enumeration of total microbial counts was carried out using the pour plating technique. The bacterial isolates were identified using Bergey's Manual of Determinative Bacteriology based on the results obtained from microscopic examination, cultural and morphological examination and biochemical tests. Meanwhile, the fungal isolates were identified using the Atlas and Compendium of Soil Fungi, based on the results obtained from cultural and morphological examination, as well as microscopic examination. The antibiotic and antifungal susceptibility pattern of the isolated microorganisms was also determined. Results showed that the ATM keypads and shuttle door handles contained Staphylococcus aureus (8.82%), Bacillus spp. (32.35%), Proteus mirabilis (8.82%), Escherichia coli (5.88), Salmonella spp. (5.88%), Enterobacter cloacae (5.88%), Klebsiella pneumoniae (2.94%), Citrobacter freundii (2.94%), Vibrio cholerae (2.94%), Serratia marcescens (2.94%), Aspergillus spp. (5.88%), Cladosporium sp. (2.94%), Geomyces sp. (2.94%), Oidiodendron griseum robak (2.94%), Penicillium paneum (2.94%) and Fusarium culmorum (2.94%). The zone of inhibition for the bacteria and fungi isolates ranged from 4mm to 36 mm, with ciprofloxacin being the most effective antibiotic. This study shows that campus shuttles and ATMs, aside from their primary functions, could also serve as a means of transmitting both pathogenic and non-pathogenic microorganisms, which pose public health risks. Personal hygiene and sanitation, such as hand washing and the use of hand sanitizer to clean hands, could serve as a means of reducing the incidence of microbial transmission.

Study on Antibiotic Resistance Profiles Exhibited by Vibrio Species Isolated from Landfill Soils in Zaria Metropolis, Northern Nigeria

Study’s Novelty/Excerpt This study investigates the occurrence and antibiotic resistance profiles of Vibrio species isolated from landfill soils in Zaria Metropolis, with a focus on environmental reservoirs of antibiotic resistance. The research uniquely identifies a high prevalence of Vibrio cholerae non-O1 among the isolates and reveals significant multidrug resistance (MDR), particularly against Ampicillin, while also showing complete susceptibility to Gentamicin and Chloramphenicol. These findings highlight the potential for landfills to serve as environmental reservoirs of antibiotic resistance, underscoring the need for further research to understand the implications for public health and environmental management. Full Abstract Antibiotic resistance in bacteria presents a major risk to public health and the environment. Infections caused by Vibrio species continue to be a serious public health concern. This study investigated the occurrence and antibiotic resistance profiles of Vibrio species isolates from landfill soils in Zaria Metropolis. A total of one hundred and twenty (120) soil samples were collected from designated landfills in four locations in Sabon-Gari, Samaru, Tudun-Wada, and Zaria City. Vibrio species were isolated using Thiosulphate citrate bile salt sucrose (TCBS) agar. Bacteriological analysis of the soil samples revealed 9(7.50%) Vibrio species isolates with Vibrio cholerae non-O1 exhibiting the highest prevalence of 4 (3.33%) among all isolates. Using the Kirby-Bauer method, the isolates were tested for susceptibility against ten commonly used antibiotics belonging to three different classes. The highest resistance was to Ampicillin (88. 89%), while all the isolates (100%) showed susceptibility to Gentamicin and Chloramphenicol. Five isolates (55.56%) were Multidrug Resistance (MDR). The highest Multidrug Resistance (MDR, 60%) was observed in Vibrio cholerae non-O1. The isolate resistant to the highest number of antibiotics was obtained from the Tudun-Wada sample location. Three isolates (33.33%) showed resistance to 4 antibiotics, while 2 isolates, 1(11.11%) each were resistant to 5 and 6 antibiotics. The isolates were Multiple Antibiotic Resistance (MAR) to 4-6 antibiotics, and four different phenotypic resistance profiles were observed among them. The origin and varying levels of resistance to multiple antibiotics indicated could be traced to the faecal constituent of the waste in landfills produced by people or animals that have been treated indiscriminately with various antibiotics or items containing residual antimicrobial agents disposed of in dump soils, highlighting the potential environmental reservoirs of antibiotic resistance and call for further research to understand the implications for public health and environmental management.

High Biofilm-Forming Multidrug-Resistant Salmonella Infantis Strains from the Poultry Production Chain.

The ability of Salmonella species to adhere to surfaces and form biofilms, leading to persistent environmental reservoirs, might represent a direct link between environmental contamination and food processing contamination. The purpose of this study was to investigate the biofilm-forming ability of 80 multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL) producing Salmonella enterica serovar Infantis strains isolated from the broiler food chain production through whole genome sequencing (WGS), PCR, and morphotype association assays. Biofilm formation was quantified by testing the strains at two different temperatures, using 96-well polystyrene plates. The rough and dry colony (rdar) morphotype was assessed visually on Congo red agar (CRA) plates. Based on our results, all tested S. Infantis strains produced biofilm at 22 °C with an rdar morphotype, while at 37 °C, all the isolates tested negative, except one positive. Most isolates (58.75%) exhibited strong biofilm production, while 36.25% showed moderate production. Only 5 out of 80 (6.25%) were weak biofilm producers. WGS analysis showed the presence of the fim cluster (fimADF) and the csg cluster (csgBAC and csgDEFG), also described in S. Typhimurium, which are responsible for fimbriae production. PCR demonstrated the presence of csgD, csgB, and fimA in all 80 S. Infantis strains. To our knowledge, this is the first study comparing the effects of two different temperatures on the biofilm formation capacity of ESBL producing S. Infantis from the broiler production chain. This study highlights that the initial biofilm components, such as curli and cellulose, are specifically expressed at lower temperatures. It is important to emphasize that within the broiler farm, the environmental temperature ranges between 18-22 °C, which is the optimum temperature for in vitro biofilm formation by Salmonella spp. This temperature range facilitates the expression of biofilm-associated genes, contributing to the persistence of S. Infantis in the environment. This complicates biosecurity measures and makes disinfection protocols on the farm and in the production chain more difficult, posing serious public health concerns.

Molecular Characterization and Phylogenetic analyses of Rotaviruses Circulating in Municipal Sewage and Sewage-Polluted River Waters in Durban Area, South Africa.

Globally, rotavirus continues to be the leading etiology of severe pediatric gastroenteritis, and transmission of the disease via environmental reservoirs has become an emerging concern in developing countries. From August to October 2021, a total of 69 samples comprising 48 of raw and treated sewage, and 21 surface waters, were collected from four Durban wastewater treatment plants (DWWTP), and effluent receiving rivers, respectively. Rotaviruses recovered and identified from the samples were subjected to sequencing, genotyping, and phylogenetic analysis. Of the 65 (94.2%) rotavirus-positive samples, 33.3% were from raw sewage, 16% from activated sludge, 15.9% from final effluents, and 29.0% were from the receiving river samples. A total of 49 G and 41 P genotypes were detected in sewage while 15 G and 22 P genotypes were detected in river samples. G1 genotype predominated in sewage (24.5%) followed by G3 (22.4%), G2 (14.3%), G4 (12.2%), G12 (10.2%), G9 (8.2%), and G8 (6.1%). Similarly, G1 predominated in river water samples (33.3%) and was followed by G2, G4 (20.0% each), G3, and G12 (13.3% each). Rotavirus VP4 genotypes P[4], P[6], and P[8] accounted for 36.6%, 29.3%, and 9.8%, respectively, in sewage. Correspondingly, 45.5%, 31.8%, and 13.6% were detected in river samples. The G and P genotypes not identified by the methods used were 2.1% versus 24.3% and 0.1% versus 9.1% for sewage and river water samples, respectively. Sequence comparison studies indicated a high level of nucleotide identity in the G1, G2, G3, G4, G8 VP7, and P[4], P[6], and P[8] VP4 gene sequences between strains from the environment and those from patients in the region. This is the first environmental-based study on the G and P genotypes diversity of rotavirus in municipal wastewater and their receiving rivers in this geographical region. The high similarity between environmental and clinical rotavirus strains suggests both local circulation of the virus and potential exposure risks. In addition, it highlights the usefulness of sewage surveillance as an additional tool for an epidemiological investigation, especially in populations that include individuals with subclinical or asymptomatic infections that are precluded in case-based studies.

Unravelling the mechanisms of antibiotic and heavy metal resistance co-selection in environmental bacteria.

The co-selective pressure of heavy metals is a contributor to the dissemination and persistence of antibiotic resistance genes in environmental reservoirs. The overlapping range of antibiotic and metal contamination and similarities in their resistance mechanisms point to an intertwined evolutionary history. Metal resistance genes are known to be genetically linked to antibiotic resistance genes, with plasmids, transposons, and integrons involved in the assembly and horizontal transfer of the resistance elements. Models of co-selection between metals and antibiotics have been proposed, however, the molecular aspects of these phenomena are in many cases not defined or quantified and the importance of specific metals, environments, bacterial taxa, mobile genetic elements, and other abiotic or biotic conditions are not clear. Co-resistance is often suggested as a dominant mechanism, but interpretations are beset with correlational bias. Proof of principle examples of cross-resistance and co-regulation has been described but more in-depth characterizations are needed, using methodologies that confirm the functional expression of resistance genes and that connect genes with specific bacterial hosts. Here, we comprehensively evaluate the recent evidence for different models of co-selection from pure culture and metagenomic studies in environmental contexts and we highlight outstanding questions.

Tackling Carbapenem Resistance and the Imperative for One Health Strategies-Insights from the Portuguese Perspective.

Carbapenemases, a class of enzymes specialized in the hydrolysis of carbapenems, represent a significant threat to global public health. These enzymes are classified into different Ambler's classes based on their active sites, categorized into classes A, D, and B. Among the most prevalent types are IMI/NMC-A, KPC, VIM, IMP, and OXA-48, commonly associated with pathogenic species such as Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The emergence and dissemination of carbapenemase-producing bacteria have raised substantial concerns due to their ability to infect humans and animals (both companion and food-producing) and their presence in environmental reservoirs. Adopting a holistic One Health approach, concerted efforts have been directed toward devising comprehensive strategies to mitigate the impact of antimicrobial resistance dissemination. This entails collaborative interventions, highlighting proactive measures by global organizations like the World Health Organization, the Center for Disease Control and Prevention, and the Food and Agriculture Organization. By synthesizing the evolving landscape of carbapenemase epidemiology in Portugal and tracing the trajectory from initial isolated cases to contemporary reports, this review highlights key factors driving antibiotic resistance, such as antimicrobial use and healthcare practices, and underscores the imperative for sustained vigilance, interdisciplinary collaboration, and innovative interventions to curb the escalating threat posed by antibiotic-resistant pathogens. Finally, it discusses potential alternatives and innovations aimed at tackling carbapenemase-mediated antibiotic resistance, including new therapies, enhanced surveillance, and public awareness campaigns.

Targeted inactivation of multidrug-resistant Alcaligenes faecalis in pig farm WWTPs by mixed bacteriophages to diminish the risk of pathogenicity and antibiotic resistance dissemination

Wastewater treatment plants (WWTPs) at pig farms are significant environmental reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In particular, contamination by multidrug-resistant Alcaligenes faecalis (MDR-AF) poses an increasingly severe threat to human health. However, no safe and effective method is currently available to hinder its dissemination in the environment. In this study, two hitherto unreported bacteriophages were screened. In addition, qPCR experiments demonstrated that applying these bacteriophage preparations to wastewater significantly eradicates MDR-AF and reduces ARGs by 0.7–2.5 orders of magnitude (P < 0.05), thereby substantially diminishing the risk of antibiotic resistance transmission. Furthermore, various characterizations, bacteriophage genomic analysis, and microbial community analysis indicated that these bacteriophage preparations possess safety, specificity, and high resilience, rendering them an efficient and eco-friendly biological control measure.

The impact of porous structure on oil–water two-phase flow under CO2 environment in continental shale reservoirs

CO2 applications for enhanced oil recovery and storage in continental shale reservoirs are promising, and there is a need to evaluate the impact of porous structure on oil–water two-phase flow under CO2 environment. In this study, first, digital cores of quartz-rich, carbonate-rich, and clay-rich shales are established using Focused Ion Beam Scanning Electron Microscopy scanning data processed through generative adversarial networks. Subsequently, the pore networks generated by digital cores are quantitatively analyzed using the generalized extreme value distribution. Finally, pore network modeling is carried out to elucidate the effect of porous structural differences on oil–water flow considering CO2 dissolution and capillary forces. The results show that quartz-rich shale, characterized by nanopore intergranular dominance and the highest pore network connectivity, demonstrates the highest relative permeability of the oil phase. Carbonate-rich shale exhibits intermediate relative permeability of oil phase, while clay-rich shale exhibits the worst. The dissolution of CO2 reduces oil–water interfacial tension and oil viscosity, enhances oil mobilization within nanopores, and notably increases the relative permeability of the oil phase. The permeability of the oil phase is governed by pore structure, displaying positive correlations with core heterogeneity, pore radius, coordination number, and throat length, and negative correlations with throat radius.

Small irrigation reservoir for sustainable fish production and livelihoods

The present study is undertaken on Barnoo reservoir to find out how the environment of a small irrigation reservoir would be sustainable in terms of fish production as well as socio-economic wellbeing or upliftment of people (fishers) associated with it.. KEYWORDS :Barnoo reservoir, sustainable fish production, socio-economic status, fishers

Advances in well design and integrity: Areview of technological innovations and adaptive strategies for global oil recovery

Advances in well design and integrity are critical for enhancing global oil recovery rates. This review reviews technological innovations and adaptive strategies that drive efficiency and sustainability in oil production. The review discusses key themes such as reservoir characterization, wellbore stability, drilling fluids, and completion techniques. It highlights how these factors impact well integrity and production rates. The review emphasizes the importance of integrating innovative technologies and adaptive strategies to overcome challenges in complex reservoir environments. Key findings include the importance of reservoir characterization in designing wells that optimize recovery rates. It also highlights the role of wellbore stability in ensuring long-term integrity and reducing risks associated with drilling operations. The review discusses the advancements in drilling fluids, including the use of nanotechnology and biodegradable materials, to improve wellbore stability and minimize environmental impact. Additionally, the abstract explores advances in completion techniques, such as intelligent completions and sand control systems, to enhance production efficiency and reservoir management. It also discusses the integration of digital technologies, such as data analytics and artificial intelligence, to optimize well performance and reduce operational costs. The review concludes by highlighting the need for continued research and development to address the evolving challenges in global oil recovery. It emphasizes the importance of collaboration between industry stakeholders, research institutions, and regulatory bodies to drive innovation and ensure sustainable practices in oil production. Overall, the abstract provides a comprehensive overview of the technological innovations and adaptive strategies that are shaping the future of well design and integrity in the global oil industry. his review covers the evolution of well design practices, the application of new materials and technologies, and the strategic adaptations required to maintain operational safety and efficiency in diverse environmental conditions.

Estimation of shale adsorption gas content based on machine learning algorithms

Shale gas is a clean and low-carbon natural gas resource. It mainly exists in both adsorbed and free states in pores and fractures. To accurately estimate the in-situ adsorption gas content (AGC), which is helpful in resource evaluation and development planning, methane isothermal adsorption data and geological parameters have been collected, such as total organic carbon (TOC) content, thermal maturity (Ro), siliceous mineral content (VQF), total clay content (VTC), water content (VWC), and temperature (T). Using machine learning (ML) methods, the in-situ AGC estimation models were constructed and optimized. Various geological factors affecting methane adsorption were evaluated, and an application was conducted in the Wufeng-Formation shale. The results reveal that the four ML models have higher accuracy in predicting Langmuir volume (VL) and Langmuir pressure (PL) than empirical formulas and linear regression models. Among the four ML models, the Random Forest Regression (RFR) and eXtreme Gradient Boosting Regression (XGBR) models perform the best, with R2 higher than 0.85. TOC and T are the main factors affecting methane adsorption, followed by Ro and VQF, while the importance of VTC and VWC is relatively low. According to different combinations of geological parameters, there are three schemes for ML model construction. Among them, scheme 1 based on all six geological parameters has the highest accuracy and is most beneficial to predicting AGC. Gradually reducing VWC, VTC, and VQF results in a slight decrease in accuracy, with R2 decreasing by at most about 6%, scheme 2 is suitable for rougher estimation of AGC. Further removal of T and Ro results in a significant decrease in accuracy, with R2 decreasing by up to 50% and MRE exceeding 30%, rendering scheme 3 unavailable for AGC prediction. The AGC of Wufeng-Longmaxi shale is successfully predicted based on XGBR model, with AGC mainly in 1.0 m3/ton-4.0 m3/ton. Overall, the ML models based on multiple geological parameters can simulate the real reservoir environment and achieve rapid and accurate estimation of in-situ AGC.

Investigation of the Stability Mechanism of Stimulus-Responsive Wormlike Micelle-CO2 Foams in the Oil Phase.

Foam flooding is an important tool for reservoir development. This study aims to further investigate the interaction between stimulus-responsive wormlike micelle (WLM)-CO2 foams and crude oil. We performed micromorphology experiments as our major studies and used molecular dynamics simulations as an auxiliary tool for interfacial analysis. We utilized foam generation, liquid separation, and defoaming as the entry points of experimental research and energy as the quantitative assessment index to investigate the dynamic process of the action of different oil contents and oil phase types in a DOAPA@NaSal-H+ foam system. We also examined the role of NaSal in the generation and development of the foam system. Results indicated that the law of crude oil's effect on foam could be summarized as "low contents are beneficial and high contents are harmful." In addition, although the DOAPA@NaSal-H+ foam system has high compatibility for saturated and aromatic hydrocarbons, it is highly suitable for application in reservoir environments with relatively high asphaltene and resin contents. Through combined experimental and simulation approaches, we clarified the law governing the stability of the DOAPA@NaSal-H+ foam system in different oil-containing environments, identified the key role of NaSal, and provided a reference for the targeted application of the DOAPA@NaSal-H+ foam system in different oil reservoirs.

Interfacial tension and wettability alteration during hydrogen and carbon dioxide storage in depleted gas reservoirs

The storage of CO2 and hydrogen within depleted gas and oil reservoirs holds immense potential for mitigating greenhouse gas emissions and advancing renewable energy initiatives. However, achieving effective storage necessitates a thorough comprehension of the dynamic interplay between interfacial tension and wettability alteration under varying conditions. This comprehensive review investigates the multifaceted influence of several critical parameters on the alterations of IFT and wettability during the injection and storage of CO2 and hydrogen. Through a meticulous analysis of pressure, temperature, treatment duration, pH levels, the presence of nanoparticles, organic acids, anionic surfactants, and rock characteristics, this review elucidates the intricate mechanisms governing the changes in IFT and wettability within reservoir environments. By synthesizing recent experimental and theoretical advancements, this review aims to provide a holistic understanding of the processes underlying IFT and wettability alteration, thereby facilitating the optimization of storage efficiency and the long-term viability of depleted reservoirs as carbon capture and storage or hydrogen storage solutions. The insights gleaned from this analysis offer invaluable guidance for researchers, engineers, and policymakers engaged in harnessing the potential of depleted reservoirs for sustainable energy solutions and environmental conservation. This synthesis of knowledge serves as a foundational resource for future research endeavors aimed at enhancing the efficacy and reliability of CO2 and hydrogen storage in depleted reservoirs.