Search Results (1,012)

Background: Intensive poultry production systems can act as reservoirs for antibiotic-resistant and multidrug-resistant (MDR) Escherichia coli, posing a public health risk through food and environmental transmission. Methods: This study investigated the genomic characteristics of antibiotic-resistant E. coli isolated from an intensive poultry production system in the uMgungundlovu District, KwaZulu-Natal, South Africa. Chicken litter, wastewater, and floor swab samples were collected over three consecutive production cycles. Putative E. coli isolates were detected using the Colilert-18 system, cultured on eosin methylene blue agar, and genomically confirmed by quantitative PCR (q-PCR) targeting the uidA gene. Whole genome sequencing was performed using the Illumina MiSeq platform, followed by bioinformatic analyses to assess resistance genes, mobile genetic elements, and phylogenetic relationships. Results: Of 150 presumptive E. coli, 70 were genomically confirmed as E. coli and resistant to at least one antibiotic, with 74% exhibiting multidrug resistance. Resistance was highest to tetracycline (100%), ampicillin (94%), and trimethoprim–sulfamethoxazole (76%), while ciprofloxacin resistance was rare (3%). Genomic analysis identified multiple antibiotic resistance genes conferring resistance to fluoroquinolones, β-lactams, aminoglycosides, amphenicols, fosfomycin, and sulfonamides, as well as the disinfectant resistance gene qacI. These genes were frequently associated with mobile genetic elements, including plasmids, integrons, transposons, and insertion sequences. Predominant sequence types included ST155, ST48, ST1286, and ST602, with phylogenetic relatedness to poultry-associated isolates from Cameroon, Ghana, Nigeria, and Tanzania, as well as environmental E. coli strains previously identified in South Africa and Ghana. Conclusions: The detection of diverse, mobile MDR E. coli lineages in poultry environments clearly signals a substantial risk for resistance gene dissemination into the food chain and surrounding ecosystems. Immediate attention and intervention are warranted to mitigate public health threats. Full article

The use of biosolids in agriculture enhances soil fertility and organic matter, yet concerns remain over the accumulation of contaminants of emerging concern in soils and food crops. Despite increased land application, long-term field-based evidence on the environmental fate and plant uptake of these compounds is limited. This study hypothesized that prolonged biosolid application improves soil carbon and nitrogen without promoting triclosan (TCS) or sulfamethoxazole (SMX) persistence or uptake under rainfed and rainfed + irrigation maize systems. Over a decade and half, a field trial was conducted with biosolids applied at rates of 0, 4, 8, and 16 t ha⁻¹ yr⁻¹. Soil samples were analyzed for organic carbon, total nitrogen, pH, electrical conductivity, TCS, and SMX. Maize stem, leaves, and grain were similarly analyzed for TCS and SMX. Results showed that biosolids significantly improved soil organic carbon and nitrogen (p ≤ 0.0001), but also increased soil acidification and salinity. SMX was not detected in either soil or plant tissues at any rate. Although TCS was absent in soils six months post-application, it was detected in maize shoots and grains at 8 and 16 t ha⁻¹ yr⁻¹, highest in stems (6.66–8.92 ng g⁻¹) and lowest in grains (3.25–4.28 ng g⁻¹). Estimated dietary intake was well below health risk thresholds. These findings support biosolid application ≤ 16 t ha⁻¹ yr⁻¹ as a safe and effective treatment for improving soil fertility in maize systems. Future research should explore transformation products, microplastics, and cumulative exposure under varied agroecosystems. Full article

Iatrogenic maxillary sinusitis accounts for a significant proportion of unilateral sinus infections. This report describes a 36-year-old HIV-positive patient with Serratia marcescens chronic left maxillary sinusitis and ethmoiditis caused by migration of a dental implant into the maxillary sinus. The implant was successfully removed endoscopically via functional endoscopic sinus surgery. Histopathological examination revealed polypoid mucosa with chronic inflammation, while microbiological culture grew Serratia marcescens, an uncommon and opportunistic pathogen. Targeted antibiotic therapy with trimethoprim/sulfamethoxazole was administered for 20 days. Six-month follow-up revealed complete remission without recurrence of sinusitis. Full article

Background: Cutaneous wounds are common in outpatient care, but national patterns of who manages them and how antimicrobials are used remain unclear. Objectives: To characterize outpatient specialty involvement and antimicrobial use for acute and chronic cutaneous wound visits in the United States. Methods: We conducted a retrospective cross-sectional analysis of 2011–2019 National Ambulatory Medical Care Survey (NAMCS) data. Cutaneous wound visits were identified using prespecified ICD-9-CM and ICD-10-CM codes and classified as acute (open or traumatic wounds and burns) or chronic (pressure injuries and lower-limb ulcers). Survey weights were applied to estimate national visit volumes, specialty shares, and antimicrobial utilization patterns. Results: We identified 45.1 million cutaneous wound visits, representing 0.8% of all outpatient visits, of which about two thirds were acute and one third chronic. Primary care physicians accounted for the largest share of wound visits, while dermatologists managed 3.9% of overall wound visits, 2.4% of acute visits, and 7.4% of chronic visits. Among 156.6 million medications recorded at wound visits, antimicrobials represented 13.1% overall, 14.9% in acute visits, and 10.2% in chronic visits. Cephalexin accounted for 32.1% of antimicrobial medications overall and 39.2% in acute visits, whereas chronic wound visits had a more heterogeneous antimicrobial profile that included topical mupirocin, cephalexin, trimethoprim–sulfamethoxazole, and topical nystatin. Conclusions: Outpatient cutaneous wound care in the United States is delivered predominantly by primary care clinicians and relies heavily on a small set of systemic and topical antimicrobials, highlighting opportunities to strengthen antimicrobial stewardship and expand dermatology’s role in chronic wound management. Full article

Electrochemical advanced oxidation processes based on peroxymonosulfate (PMS-EAOPs) have shown great promise for eliminating organic pollutants from water. However, earlier research primarily concentrated on pollutant degradation at the cathode, with little attention given to the anode’s role in PMS-EAOPs. In this work, we developed a PMS-EAOP system using nitrogen-doped carbon nanotubes (N-CNTs) as the electrocatalyst and examined the degradation of pollutants (acetamiprid (ATP) and sulfamethoxazole (SMX)) at both the cathode and anode. Our findings indicate that SMX was rapidly degraded at both electrodes, while ATP was effectively broken down only at the cathode, demonstrating the selective nature of PMS-EAOP. At a voltage of −2 V and 2.5 mM PMS, the pseudo-first-order rate constant (k_obs) for ATP at the cathode reached 0.122 min⁻¹, with over 92% removal within 30 min. In contrast, the anode exhibited high selectivity, removing ~75% of SMX (k_obs = 0.041 min⁻¹) while less than 20% of ATP was degraded. Analysis of reactive oxygen species showed that hydroxyl and sulfate radicals were produced and contributed to pollutant degradation at the cathode. In contrast, selective oxidation occurred at the anode, likely driven by direct electrolysis-induced nonradical oxidation responsible for the selective degradation. Phosphates and bicarbonates significantly inhibited the degradation of pollutants in the PMS-EAOP process (31.7–76.4%). In contrast, chloride ions exhibited an electrode-dependent effect, with the anode being less susceptible to interference from common water anions. Overall, this study highlights that while PMS-EAOP can selectively remove contaminants, the influence of water matrix components must be taken into account when treating real wastewater. Full article

This study investigated the clinical and genomic characteristics of Enterobacter cloacae complex (ECC) and Klebsiella aerogenes bloodstream infections (BSIs) in pediatric patients. A total of 115 BSI episodes (ECC: 86, K. aerogenes: 29) from 110 children hospitalized between 2011 and 2024 were retrospectively analyzed. Whole-genome sequencing was performed on available isolates to determine species, sequence types, and antimicrobial resistance (AMR) genes. Clinical characteristics, antibiotic usage, and outcomes were compared between groups. Patients with K. aerogenes BSI were younger and more likely to be preterm or diagnosed with urosepsis, while ECC infections were more frequently associated with hematologic malignancies. According to a multivariable analysis of the entire cohort (n = 115), K. aerogenes infection (OR [6.26], 95% CI [1.36–28.78]) and gentamicin resistance (OR [10.06], 95% CI [1.88–53.87]) were independently associated with 30-day mortality. Enterobacter hormaechei was the most common ECC species (68.4%) and exhibited the highest prevalence of AMR genes, particularly those conferring resistance to aminoglycosides, β-lactams, and trimethoprim–sulfamethoxazole. In contrast, K. aerogenes harbored few resistance genes. Multi-locus sequence typing analysis revealed high genetic diversity in both ECC and K. aerogenes, without evidence of dominant clonal expansion. Despite similarities in clinical presentation, ECC and K. aerogenes exhibit distinct age distributions, resistance profiles, and genetic diversity in pediatric BSIs. These findings underscore the importance of species-level identification and continued genomic surveillance to inform empirical antibiotic strategies and prevent the spread of resistant strains. Full article

The widespread occurrence of pharmaceutical contaminants in aquatic environments poses significant risks to ecosystems and public health, necessitating the development of efficient and sustainable treatment technologies. Herein, a visible-light (VL)–active zinc single-atom catalyst supported on biochar (SAZn@BC) was synthesized via pyrolysis and applied for the degradation of ibuprofen (IBP), sulfamethoxazole (SMX), trimethoprim (TMP), and carbamazepine (CBZ) in water. Structural characterization confirmed the presence of g-C₃N₄ domains, abundant oxygen-containing functional groups, and atomically dispersed Zn sites with a Zn–N₄ coordination environment. Under VL irradiation, SAZn@BC achieved degradation efficiencies of 43.9%, 64.4%, and 61.9% for IBP, SMX, and TMP, respectively, within 30 min, while CBZ exhibited limited removal. Mechanistic investigations combining quenching experiments, electrochemical analyses, and X-ray photoelectron spectroscopy revealed that superoxide and hydroperoxyl radicals were the dominant reactive oxygen species, with hydroxyl radicals and singlet oxygen contributing to a lesser extent. In addition, a nonradical pathway involving direct interfacial electron transfer between oxygen functional groups on the biochar support and pharmaceutical molecules played a critical role, mediated by single-atom Zn sites and enhanced under VL irradiation. These findings demonstrate that SAZn@BC enables synergistic radical and nonradical pathways for pharmaceutical degradation and represents a promising strategy for water treatment applications. Full article

In this study, inverse gas chromatography (IGC) was applied to characterize the key surface physicochemical properties of carbon–mineral composites and to clarify how these properties relate to removal efficiencies of selected antibiotics, with particular emphasis on surface energetic and acid–base characteristics rather than bulk structural parameters. The dispersive component of surface free energy and the acid–base characteristics (K_a/K_b ratio) were determined, alongside measurements of carbon content, while specific surface areas were compared with data reported previously. We found that there is no clear correlation between bulk structural characteristics and the removal efficiency of ciprofloxacin, doxycycline, sulfamethoxazole, and tetracycline. In contrast, the removal of all investigated antibiotics was found to be correlated with the dispersive component of surface free energy and the K_a/K_b ratio. The results suggest that surface energetic parameters and acid–base properties are more closely associated with antibiotic adsorption behavior than basic structural characteristics alone. These findings demonstrate that IGC provides valuable insight into adsorption processes and highlight the importance of surface physicochemical properties for interpreting and predicting the adsorption properties of carbon–mineral composites. Full article

Chemical contaminants are increasingly detected in freshwater environments, yet the physiological and molecular responses of many non-model freshwater invertebrates to acute chemical stress remain poorly understood. In this study, we investigated the physiological and transcriptomic responses of the freshwater hydrozoan Craspedacusta sowerbii to two widespread aquatic pollutants: the antibiotic sulfamethoxazole (20 μM) and the heavy metal salt CdSO₄ (10 μM). Morphological and behavioral observations showed that sulfamethoxazole exposure led to reduced motility and body shrinkage, whereas cadmium exposure caused rapid loss of movement and complete mortality within 24 h. RNA sequencing revealed distinct transcriptional response patterns to the two stressors. Sulfamethoxazole exposure primarily induced the up-regulation of genes associated with oxidative stress, apoptosis, immune responses, and signaling pathways, suggesting an active but limited stress-adaptation response. In contrast, cadmium exposure resulted in extensive down-regulation of genes involved in metabolic pathways, cell cycle regulation, fatty acid metabolism, and anti-aging processes, suggesting severe disruption of core metabolic processes. Comparative pathway analyses identified both shared stress-related responses and pollutant-specific transcriptional signatures, with cadmium exerting markedly stronger inhibitory effects at both physiological and molecular levels. These results reveal clear thresholds of stress tolerance and response failure in C. sowerbii under chemical pollution, and highlight its ecological sensitivity to water quality deterioration. Together, these findings provide mechanistic insight into acute pollutant-induced stress responses in a freshwater Cnidarian and offer a useful reference for understanding how freshwater invertebrates respond to short-term chemical disturbances. Full article

Antibiotics represent a unique and diverse group of drugs, which are known to exert deleterious effects on non-target species and contribute to the phenomenon of antimicrobial resistance. With central inclusion on the EU Surface Water Watch List, and reported known affects in multiple model organisms, the importance of the sufficient monitoring of antibiotics in the aquatic environment has been highlighted. Most studies report the impact of individual antibiotics following exposure for a single generation in animals. In this study, we assessed the impact of four antibiotics with different modes of action (amoxicillin, trimethoprim, erythromycin, and sulfamethoxazole) and their mixture on the sentinel species Daphnia magna over three generations, via biochemical markers and a targeted metabolomic analysis of central metabolic pathways. No mortality was observed at 50 mg/L of each selected antibiotic and their composite mixture. Thus, a working concentration of 1 mg/L was chosen to progress this study. Results indicated that enzyme activity was particularly sensitive to exposure to amoxicillin and the mixture, whereas trimethoprim and the mixture induced the most metabolic changes in glycolysis and the TCA cycle. Additionally, the quaternary mixture had a stronger impact on the first generation of daphnids, altering the activity of β-galactosidase, glutathione S-transferase, and acid and alkaline phosphatase, suggesting that Daphnia can adapt to stress caused by antibiotics. Full article

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in Sarawak, Malaysian Borneo, where it is represented by a unique gentamicin-susceptible population. Despite trimethoprim-sulfamethoxazole (co-trimoxazole) being the cornerstone of eradication therapy, emerging reports of elevated minimum inhibitory concentrations (MICs) among Sarawak isolates have raised concerns over its clinical efficacy. We performed a retrospective and comprehensive antibiotic susceptibility assessment of clinical B. pseudomallei isolates from hospitals across Sarawak. Susceptibility to trimethoprim-sulfamethoxazole was determined using disk diffusion and the E-test, interpreted by both CLSI and EUCAST guidelines. Resistance to the individual components, trimethoprim and sulfamethoxazole, was characterized by broth microdilution. The results demonstrated a high prevalence of trimethoprim-sulfamethoxazole susceptibility, with 96.3% of isolates susceptible by CLSI criteria and 97.6% by EUCAST criteria. Interestingly, broth microdilution revealed that resistance to trimethoprim and sulfamethoxazole individually did not confer resistance to the synergistic combination. Our analysis validated CLSI guidelines as the most reliable standard for antimicrobial resistance surveillance in this region. This study provides evidence that trimethoprim-sulfamethoxazole remains effective for melioidosis treatment in Sarawak, offering crucial reassurance to clinicians. The paradoxical finding of susceptibility to the drug combination despite resistance to its individual components underscores the critical importance of the synergistic activity of trimethoprim-sulfamethoxazole and highlights the need for further investigation into the molecular basis of resistance in this distinct B. pseudomallei population. Full article

Background: Stenotrophomonas maltophilia is an increasingly important multidrug-resistant opportunistic pathogen frequently isolated from clinical, environmental, and plant-associated niches. Despite its medical relevance, the global population structure, species-complex boundaries, and genomic determinants of antimicrobial resistance (AMR) and ecological adaptation remain poorly resolved, partly due to inconsistent annotations and fragmented genomic datasets. Methods: Approximately 2400 genome assemblies annotated as Stenotrophomonas maltophilia were available in the NCBI Assembly database at the time of query. After pre-download filtering to exclude metagenome-assembled genomes and atypical lineages, 1750 isolate genomes were retrieved and subjected to stringent quality control (completeness ≥ 90%, contamination ≤ 5%, ≤500 contigs, N50 ≥ 10 kb, and ≤1% ambiguous bases), yielding a final curated dataset of 1518 high-quality genomes used for downstream analyses. Genomes were assessed using CheckM, annotated with Prokka, and compared using average nucleotide identity (ANI), pan-genome analysis, core-genome phylogenomics, and functional annotation. AMR genes, mobile genetic elements (MGEs), and metadata (source, host, and geographic origin) were integrated to assess lineage-specific genomic features and ecological distributions. Results: ANI-based clustering resolved the S. maltophilia complex into multiple distinct genomospecies and revealed extensive misidentification of publicly deposited genomes. The pan-genome was highly open, reflecting strong genomic plasticity driven by accessory gene acquisition. Core-genome phylogeny resolved well-supported clades associated with clinical, environmental, and plant-related niches. Resistome profiling showed widespread intrinsic MDR determinants, with certain lineages enriched for efflux pumps, β-lactamases, and trimethoprim–sulfamethoxazole resistance markers. MGE analysis identified lineage-specific integrative conjugative elements, prophages, and transposases that correlated with source and geographic distribution. Conclusions: This large-scale analysis provides the most comprehensive genomic overview of the S. maltophilia complex to date. Our findings clarify species boundaries, highlight substantial taxonomic misannotation in public databases, and reveal lineage-specific AMR and mobilome patterns linked to ecological and clinical origins. The curated dataset and evolutionary insights generated here establish a foundation for global genomic surveillance, epidemiological tracking, and future studies on the evolution of antimicrobial resistance in S. maltophilia. Full article

Piscine lactococcosis is an emerging bacterial disease that threatens freshwater and marine aquaculture in the Mediterranean region. This study characterized isolates of Lactococcus garvieae and Lactococcus petauri from farmed fish through molecular identification, genomic typing and antimicrobial susceptibility testing. A total of 39 bacterial strains were analyzed using species-specific real-time PCR assays, multilocus sequence typing and broth microdilution to determine minimum inhibitory concentrations. Results suggest a temporal shift in freshwater systems, where L. garvieae predominated in earlier isolates (mainly ST13, CC4), while L. petauri (ST14, CC14) appears as the dominant species in recent years. In marine fish, only L. garvieae was detected, mainly ST95 (CC95), a lineage previously reported in Europe. Molecular variability was found in both species with lineages capable of infecting livestock and humans. Amoxicillin displayed promising results; florfenicol showed moderate activity, while flumequine exhibited no inhibitory effect. Oxytetracycline and trimethoprim–sulfamethoxazole showed variable results requiring prudent use. These region-specific susceptibility profiles provide updated baseline data to guide empirical antimicrobial therapy while awaiting laboratory confirmation, highlighting the evolution of lactococcosis in aquaculture and emphasizing the need for molecular surveillance, antimicrobial stewardship, and vaccine updates within a One Health framework to mitigate impacts on Mediterranean aquaculture and public health. Full article

Sulfamethoxazole (SMX), a widely used antibiotic, poses potential threats to ecosystems and human health due to its persistence and residues in aquatic environments. This study developed a novel intelligent water treatment system, namely Intelligent Pulsed Electrochemical Activation of NaClO₂ (IPEA_NaClO2), which integrates a FeCuC-Ti₄O₇ composite electrode with machine learning (ML) to achieve efficient SMX removal and energy consumption optimization. Six key operational parameters—initial SMX concentration, NaClO₂ dosage, reaction temperature, reaction time, pulsed potential, and pulsed frequency—were systematically investigated to evaluate their effects on removal efficiency and electrical specific energy consumption (E-SEC). Under optimized conditions (SMX 10 mg L⁻¹, NaClO₂ 60~90 mM, pulsed frequency 10 Hz, temperature 313 K) for 60 min, the IPEA_NaClO2 system achieved an SMX removal efficiency of 89.9% with a low E-SEC of 0.66 kWh m⁻³. Among the ML models compared (back-propagation neural network, BPNN; gradient boosting decision tree, GBDT; random forest, RF), BPNN exhibited the best predictive performance for both SMX removal efficiency and E-SEC, with a coefficient of determination (R²) approaching 1 on the test set. Practical application tests demonstrated that the system maintained excellent stability across different water matrices, achieved a bacterial inactivation rate of 98.99%, and significantly reduced SMX residues in a simulated agricultural irrigation system. This study provides a novel strategy for the intelligent control and efficient removal of refractory organic pollutants in complex water bodies. Full article

Background/Objectives: The expansion of intensive swine production in Córdoba, Argentina, underscores the need to assess the risks associated with antimicrobial (AM) use, whose extensive application has driven antimicrobial resistance, a major global threat within the One Health framework. This study aimed to characterize AM use practices and evaluate the epidemiological resistance profiles (non-wild-type phenotypes, NWT) of commensal Escherichia coli of fecal origin from swine farms, using epidemiological cut-off values (ECOFFs) as a surveillance criterion. Methods: An observational cross-sectional study was conducted in 19 farrow-to-finish farms in Córdoba during 2023. Information on AM use (prophylaxis, metaphylaxis, treatment) across production categories was collected. A total of 437 E. coli isolates were obtained from fecal samples, and minimum inhibitory concentrations (MICs) were determined for 10 AMs of critical importance for human and animal health. NWT phenotypes were classified according to EUCAST ECOFFs, and multidrug resistance (MDR) was assessed. Results: AM use was frequent and predominantly prophylactic (89.5% of farms), mainly through mass medication (66.3%), with macrolides and amoxicillin being the most commonly administered AMs. NWT proportions were extremely high (90–92%) for ampicillin, tetracyclines, and chloramphenicol and substantial for ciprofloxacin (50.6%), sulfamethoxazole (68.2%), and trimethoprim (44.9%). Extended-spectrum β-lactamase (ESBL)-producing phenotypes were detected. Alarmingly, 92% of isolates were classified as MDR E. coli, with homogeneous distribution across production categories. Conclusions: Findings reveal intensive and largely empirical AM use that has consolidated a stable intestinal resistome in the swine population. High MDR levels, even in categories with limited direct AM exposure or involving banned compounds, suggest that co-selection and horizontal gene transfer are key drivers of resistance. This scenario highlights the urgent need to strengthen integrated surveillance and promote prudent AM use strategies under the One Health approach to preserve therapeutic efficacy. Full article