Search Results (2,838)

Background/Objectives: Integrons are genetic platforms that allow bacteria to acquire antimicrobial resistance (AMR) genes, making them a focal point for many AMR studies and surveillance programs. This study investigated how the prevalence of integrons (intI and attI genes) in third-generation cephalosporin-resistant E. coli (3GCR-Ec) varied across three different sources (i.e., healthy children, domestic animals and urinary tract infections). The study aimed to determine how different classes of AMR genes vary among 3GCR-Ec with integrons present versus those where integrons are absent. Methods: We analyzed 3GCR-Ec isolates collected from semirural parishes of Eastern Quito, Ecuador, that included: (1) 3GCR-Ec from healthy children (n = 946), (2) 3GCR-Ec from domestic animal species (n = 673), and 3GCR-Ec from patients with urinary tract infections (UTIs) (n = 138). Genomic analyses were performed for all 1757 sequences to determine how the presence and absence of integrons was associated with AMR gene carriage. Results: Among the total sequences of 3GCR-Ec evaluated across all datasets, nearly one-third (31%) were integron-negative. 3GCR-Ec from UTI patients, however, had a higher percentage containing integrons (79%). Across all sets of 3GCR-EC, integron-positive isolates carried an average of 10.3 (±3.0 SD) AMR genes versus 4.8 (±2.5 SD) AMR genes in integron-negative isolates. This study found that between 21% to 33% of 3GCR-Ec across the three different sources lacked integrons but maintained the ability to carry diverse classes of AMR genes, including beta-lactams, aminoglycosides, tetracyclines, and multidrug resistance mechanisms (e.g., general-purpose efflux pumps). Conclusions: While integrons were associated with greater AMR genes on average, the study highlights that solely relying on integrons for tracking drug-resistant bacteria misses a substantive portion of AMR that is present in integron-negative strains. Full article

The emergence of multidrug-resistant Pseudomonas strains poses a serious threat to public health. Essential oil components, such as thymol (TH), exhibit potent antibacterial activity. However, the effects of continuous sublethal TH exposure and resulting changes to antibiotic susceptibility remain poorly understood. Here, we investigated a multi-resistant Pseudomonas psychrophila strain after TH adaptation using an integrated transcriptomic and metabolomic approach. Treatment with TH caused a significant decrease in MIC values for aminoglycosides (streptomycin, gentamicin, kanamycin) and tetracycline and increased susceptibility to five other antibiotics. Multi-omics analyses revealed coordinated changes in fatty acid metabolism (FabI downregulation and accumulation of unsaturated fatty acids), lipid A biosynthesis (LpxC downregulation), peptidoglycan synthesis (Mur genes downregulated, accompanied by increased spermine levels), and stress response pathways (such as GABA, GadA, maltose, and MalK). These results suggest that metabolic alterations and envelope remodeling potentially affect cell wall integrity and growth, which could, in turn, contribute to increased antibiotic susceptibility and re-sensitization. Overall, our findings highlight the potential of TH-mediated sensitization as a complementary strategy to restore antibiotic efficacy. Full article

Background/Objectives: Helicobacter pylori (HP) antibiotic eradication treatment in Germany is, at present, empirical according to the national guidelines. The aim of our prospective multicentre study was to implement routine susceptibility testing in daily clinical practice to facilitate resistance-oriented first-line antibiotic therapy and to collect local resistance data. Methods: From 1 January 2024 to 30 April 2025, in two German hospitals (in Bielefeld and Datteln), the patients who underwent gastroscopy and those who had biopsies for histopathology also underwent biopsies for the Helicobacter urease test (HUT). Positive HUT samples were sent for susceptibility testing: they were checked for phenotypic/cultural resistance to amoxicillin, clarithromycin, metronidazole, levofloxacin, rifampicin and tetracycline and genotypic/molecular resistance to clarithromycin and fluoroquinolones. Results: In total, in 1503 cases, both HUT and histology were performed, in which 256 (17.0%) histologies were HP-positive. We sent 311/1503 (20.7%) positive HUTs for susceptibility testing. In 120 (38.6%) of them, it was possible to culture HP, and for 118 cases, phenotypic resistance testing was performed. In 200/311 cases, PCR was also executed, with 111/200 cases being subjected to subsequent molecular resistance testing. Resistance patterns varied regionally, with metronidazole resistance observed in 3–33%, clarithromycin resistance in 16–20% and levofloxacin resistance in 13–16% cases. Conclusions: it is technically and logically feasible to perform HP antibiotic susceptibility testing via the same biopsy used for the HUT. The proposed procedures might be applied both in hospital and outpatient settings in endoscopic offices. Routine susceptibility testing is useful not only for the individual patient but also for monitoring the development of regional resistance patterns as a basis for better-targeted empiric therapy. Additionally, this approach might help to reduce the resistance dynamics at large in terms of antimicrobial stewardship. Full article

Staphylococcus aureus is a high-priority pathogen causing skin and soft tissue infections (SSTIs). The frequent resistance to anti-staphylococcal agents exhibited by this underscores the need for accurate diagnostics to guide effective therapy. Therefore, this study aimed to compare phenotypic and genotypic resistance in S. aureus isolates from nasal carriers and SSTIs and to elucidate gene-silencing mechanisms. In total, 355 S. aureus isolates (256 isolated from carriers and 79 from SSTIs) were studied for their phenotypic and genotypic resistance to β-lactams, macrolides, tetracyclines, aminoglycosides, and mupirocin. The silenced mupA gene (low prevalence: 0.6%; 2/335), linked to mupirocin resistance, was sequenced, and expression was assessed via reverse transcription qualitative PCR (RT-qPCR) in all mupA-positive isolates. SSTI isolates showed significantly higher resistance to erythromycin, gentamicin, and mupirocin, along with a higher prevalence of multidrug-resistant strains and ermC and tetM genes. Sequencing revealed multiple mutations in silent mupA, including a critical frameshift (c.372 delA) in a poly(A) tract that brings about premature truncation. RT-qPCR indicated upregulation of silent mupA variants and high variability in functional strains, suggesting that frameshift alone prevents resistance. These findings highlight silent resistance genes as key targets for advancing S. aureus surveillance and for combating emerging threats. Full article

Luminescent organic–inorganic Cu(I) halide hybrid molecular crystals exhibit remarkable structural diversity and photophysical properties, but their application in aqueous environments is often limited by insufficient stability. Herein, we report portable and reusable photoluminescent sensors based on Cu(I)–I triethylenediamine derivatives [Cu₄I₆(pr-ted)₂] and [Cu₃I₅(bz-ted)₂] (pr-ted = 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium; bz-ted = 1-benzyl-1,4-diazabicyclo[2.2.2]octan-1-ium). Their submicrometric particles exhibit intense UV-excited emissions and high photoluminescence quantum yields but limited water stability. To address this limitation, ultrasound sonication was employed to control particle size and produce stable suspensions that can be incorporated into polymeric matrices via 3D printing with photocurable resins or polylactic acid (PLA) films by drop-casting, yielding mechanically robust composites that retain their structural and optical properties. The devices used act as selective turn-off luminescent sensors for Fe³⁺ in aqueous media, with nanomolar detection limits (1.33–1.58 nM) below regulatory thresholds for drinking water. Moreover, [Cu₃I₅(bz-ted)₂] enables tetracycline detection in river water with a limit of detection of 0.038 nM. Mechanistic studies indicate that reversible photoinduced electron transfer is the primary quenching pathway, while composites maintain sensing performance over multiple reuse cycles. Full article

The gut microbiota is a central regulator of metabolic function, and its disruption by a high-fat diet (HFD) is strongly linked to obesity and metabolic impairment. This study evaluated the potential of heat-killed Lactiplantibacillus plantarum beLP1 (beLP1^®) in alleviating HFD-induced metabolic and microbial imbalances in mice. Male C57BL/6N mice were fed an HFD for 10 weeks, with or without daily oral supplementation of beLP1 (≥3 × 10¹⁰ cells). Compared with untreated HFD mice, beLP1 supplementation reduced serum triglycerides by 35% and lowered liver enzymes AST and ALT by 17% and 36%, respectively. Blood glucose levels remained similar to the HFD group throughout the study period. Shotgun metagenomic analysis revealed that beLP1 restored gut microbial diversity, increased beneficial taxa such as Akkermansia and Faecalibaculum high. and reduced pro-inflammatory species including Streptococcus sp., Mucispirillum schaedleri and Clostridium cocleatum. These microbial changes were associated with partial normalization of the Firmicutes/Bacteroidota ratio and improvements in antibiotic resistance gene (ARG) profiles. Specifically, in silico analysis of the short-chain fatty acid (SCFA) synthesis pathways indicated that the potential for acetate and propionate production was maximized in the beLP1 group, resulting in the highest relative abundance among all groups. This functional enhancement directly correlated with the enrichment of key SCFA-producing taxa, particularly Akkermansia muciniphila, confirming that increased bacterial abundance suggests an enhanced functional potential for SCFA production. Furthermore, beLP1^® induced a selective modulation of gut ARGs, significantly reducing specific subtypes such as tetracycline and multidrug efflux genes, despite a slight increase in vancomycin resistance markers. Overall, our findings suggest that beLP1^® attenuated the rate of body weight gain during the initial weeks of HFD exposure and significantly improved markers of hepatic stress and lipid metabolism. Full article

Background/Objectives: The Saker Falcon (Falco cherrug) is an endangered raptor species of ecological and conservation relevance. Despite its status, data regarding its microbiota and the prevalence of antimicrobial resistance (AMR) remain scarce, especially in Eastern Europe. This single-facility study aims to investigate the phenotypic and genotypic AMR profiles of Gram-negative bacteria isolated from captive Saker Falcons in Western Romania. Methods: Freshly voided fecal droppings were collected non-invasively from 40 clinically healthy Saker Falcons. Bacterial identification was performed using selective media and the VITEK^® 2 system. Antimicrobial susceptibility testing (AST) was conducted on a representative subset of 12 isolates. Selected resistance-associated genes were screened by conventional PCR. Results: Escherichia coli was the most prevalent 60% (n = 24/40), followed by Hafnia alvei 10% (n = 4/40) and Pseudomonas spp. 10% (n = 4/40). AST revealed phenotypic resistance among Enterobacteriaceae primarily to ampicillin 20% (n = 2/10), tetracycline 20% (n = 2/10), fluoroquinolones and sulfonamides 10% (n = 1/10), while susceptibility to imipenem 90% (n = 9/10) and gentamicin 90% (n = 9/10) remained high. The targeted resistance-associated genes were detected in selected phenotypically resistant isolates. PCR screening detected blaZ and ampC in 62.5% (n = 5/8) of tested isolates, blaOXA-61 in 37.5% (n = 3/8), blaOXA-51 in 25% (n = 2/8), tetK in 37.5% (n = 3/8), and gyrA in 12.5% (n = 1/8). The isolate used as the negative control, pansusceptible in AST, was confirmed negative for all targeted genes. Conclusions: This single-facility study provides baseline data on AMR traits in Gram-negative bacteria associated with Saker Falcons in Western Romania. Given the limited scale and isolate-based design of the study, the findings should be interpreted cautiously, but they support further investigation of wildlife-associated AMR within a One Health context. Full article

In this study, we prepare N–doped biochar loaded with β-CD, using cotton stalks as a carbon source, and evaluate its removal efficiency for tetracycline (TC) and methylene blue (MB) from aqueous solutions. This composite uniquely integrates molten salt activation, nitrogen doping, and β-CD grafting, resulting in an exceptionally high specific surface area of 1943 m²/g and abundant active sites. The findings reveal that β-CD-NKBC-1.5 (5 g of N–doped biochar loaded with 1.5 g of β-CD) demonstrates remarkable capabilities for both TC and MB removal across an extensive pH spectrum, reaching peak adsorption levels of 1269.8 and 969.4 mg/g at 308.15 K, respectively—outperforming most previously reported biochar-based adsorbents. The adsorption process is well described by the pseudo-second-order and Langmuir models, indicating that monolayer chemisorption is the dominant mechanism. β-CD-NKBC-1.5 exhibits preferential adsorption for TC and MB and maintains high adsorption efficiency even with coexisting ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, and SO₄²⁻) at concentrations up to 500 mg/L. The adsorption mechanism involves Lewis acid–base interactions, hydrogen bonding, π–π stacking, and pore filling. Full article

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is an emerging cause of invasive disease, yet contemporary genomic data from Canada remain scarce. We investigated 56 cases of invasive SDSE infection identified between 2018 and 2022 in two major tertiary care teaching hospitals in Toronto, Ontario, and characterized 49 corresponding isolates by whole-genome sequencing. Nearly three-quarters of infections were caused by the globally expanding ST20 emm type stG62647 lineage. Patients infected with this lineage were significantly older than those infected with non-ST20 lineages across both bloodstream and non-blood infections. Core-genome phylogenetic analysis revealed a highly clonal ST20 cluster, although two isolates had divergent emm types suggesting recombination at the emm locus. Non-ST20 lineages were numerically smaller and genetically more heterogeneous, including distinct sublineages within ST3 and ST34. All isolates were susceptible to β-lactams and vancomycin. Resistance to tetracycline, erythromycin, and clindamycin was detected in a subset of isolates and was associated with genes tetM, tetO, ermA, ermB, and msrD. Several antimicrobial resistance determinants were located on mobile genetic elements, including integrative and conjugative elements. Our findings provide a contemporary genomic view of invasive SDSE in Toronto, highlighting the dominance of the ST20 stG62647 lineage in agreement with recent global observations. Full article

Background/Objectives: Multidrug-resistant (MDR) Escherichia coli has increasingly been recognized as a pathogen capable of causing severe systemic infections in various animal species. However, reports describing respiratory and septicemic infections caused by MDR E. coli in guinea pigs remain scarce. The objective of this report was to describe the clinical, pathological, and microbiological findings associated with a fatal infection in a domestic guinea pig. Case Study: A 10-month-old female guinea pig (Cavia porcellus), kept as a companion animal in a household environment, presented with acute respiratory distress, lethargy, and anorexia, progressing rapidly to death within approximately 36 h of onset. Post-mortem examination revealed severe pulmonary congestion, diffuse inflammatory lesions in the trachea, and generalized vascular congestion in multiple organs. Bacteriological cultures obtained from lung and bone marrow samples yielded pure growth of Escherichia coli. Identification was confirmed using MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing demonstrated resistance to several antibiotic classes, including β-lactams, fluoroquinolones, tetracyclines, sulfonamides, and phenicols, while susceptibility was retained only to aminoglycosides. Molecular analysis revealed the presence of virulence genes involved in adhesion and iron acquisition, supporting the pathogenic potential of the isolate. Conclusions: This report highlights the ability of MDR E. coli to cause severe respiratory and systemic infections in guinea pigs. The findings underline the importance of early diagnosis, appropriate antimicrobial stewardship, and improved husbandry conditions in preventing such infections. From a One Health perspective, the circulation of resistant strains in companion animals may represent a potential risk for both environmental and human health. Full article

Antibiotic resistance genes (ARGs) are prevalent in livestock environments due to antimicrobial use, yet their airborne dispersal into human-occupied indoor spaces remains poorly characterized. We investigated whether airborne ARGs disperse from livestock stables into farmers’ homes and surrounding outdoor environments. Electrostatic dust collectors were deployed in paired pig and cow stables and their associated homes in Jutland, Denmark, to collect settled airborne dust. Pooled samples were analyzed using shotgun metagenomic sequencing. ARG dispersal patterns were assessed using FEAST source tracking and ecological similarity metrics, including shared ARG ratios and Jaccard indices. Pig production systems exhibited higher antibiotic use and stronger resistome continuity with farmers’ homes than cow systems, reflected by greater FEAST contributions (P = 0.029) and Jaccard similarity (P = 0.029). Beta-diversity analysis supported higher compositional similarity between pig stables and homes (PERMANOVA R² = 0.23, p = 0.052), whereas cow environments showed greater divergence (R² = 0.41, P = 0.035). Across environments, tetracycline, macrolide–lincosamide–streptogramin B, and aminoglycoside resistance genes dominated, consistent with livestock-specific antibiotic use patterns. Supplementary indoor–outdoor comparisons across cow, pig, and chicken stables (from an independent 2024 sampling campaign not directly comparable to the 2008 EDC-based survey) revealed contrasting dispersal dynamics, with higher bacterial species spillover from cow stables but stronger ARG overlap from pig stables. Collectively, these findings are consistent with airborne ARG connectivity across occupational and environmental interfaces and support consideration of air as a potential pathway in One Health AMR surveillance. Full article

Non-typhoidal Salmonella (NTS) is an important poultry-associated pathogen with major One Health and economic impacts, but data on its epidemiology and antimicrobial resistance in Nigeria remain limited. This study investigated the prevalence, serovar distribution, clonal relatedness, and antimicrobial resistance of NTS along the poultry production chain in Enugu State, southeastern Nigeria. A total of 2400 samples were collected, comprising feces (cecal content)/cloacal swabs from chickens (n = 1100), eggs (n = 400), chicken meat (n = 600), and stool samples from poultry workers (n = 300). Isolation and identification were performed using standard bacteriological methods, with confirmation by serotyping and polymerase chain reaction (PCR) targeting the invA gene. Genetic relatedness was assessed using enterobacterial repetitive intergenic consensus (ERIC)-PCR, and antimicrobial susceptibility was determined by the disk diffusion method. Overall, 47 (2.0%) Salmonella enterica isolates were recovered from 2400 samples, with the highest prevalence observed in eggs (3.5%), followed by human stool (3.3%), chicken meat (1.8%), and chicken feces (1.1%). Only 35 (11.8%) of the 297 sampled farms were positive for Salmonella, and recovery rates differed significantly (p = 0.0065) among sample sources. Five serotypes were identified, dominated by S. Typhimurium (57.4%), followed by S. Enteritidis (14.9%), S. Anatum (12.8%), S. Stanley (8.5%), and S. Agona (6.3%). ERIC-PCR revealed multiple clonal clusters, many containing isolates from mixed sources, indicating circulation of related strains between poultry and humans. All isolates were resistant to ampicillin, with high resistance to tetracycline (76.6%), sulphamethoxazole–trimethoprim (51.1%), and fluoroquinolones. Overall, 80.9% of isolates were multidrug-resistant, with a mean Multiple Antibiotic Resistance Index of 0.29, highest among isolates from chicken feces. Although the prevalence of NTS was low, the presence of genetically related multidrug-resistant strains across the production chain underscores the role of poultry as a reservoir for zoonotic transmission and highlights the need for coordinated One Health surveillance and antimicrobial stewardship strategies in Nigeria. Full article

Background/Objectives: Enterococcus spp. are important indicators of AMR and potential opportunistic pathogens. Urban green spaces, frequented by dogs and humans, may serve as reservoirs for resistant bacteria. This study assessed the occurrence, AMR profiles, and virulence traits of Enterococcus spp. in dog feces from urban green spaces in Porto (Portugal). Methods: In December 2023 and May 2024, 240 dog fecal samples were collected from 12 urban green spaces across Porto. Enterococcus spp. were isolated using selective culture, identified to species level, and tested for antimicrobial susceptibility following CLSI guidelines. PCR screening was performed for resistance genes (vanA, vanB, erm(A/B/C), vatD/E, tet(M/O/L/K)) and virulence genes (gelE, ace). Environmental and socioeconomic features, including vegetation density (NDVI), presence of water features, and neighborhood deprivation (EDI), were recorded to explore associations with bacterial occurrence and traits. Results: Thirty-two isolates were recovered, mainly E. faecium (n = 9) and E. faecalis (n = 7). High resistance rates were observed to tetracycline (56.3%) and quinupristin/dalfopristin (37.5%), with lower rates for vancomycin, teicoplanin, and ciprofloxacin (3.1%), and imipenem (6.3%). Tet(M) was the most prevalent resistance gene (40.6%), and gelE and ace were frequently detected, often co-occurring with resistance determinants. Distribution of resistance and virulence genes varied across green spaces, with widely used parks showing more isolates. Vegetation density and water features were not directly associated with bacterial recovery. Conclusions: Dog feces in urban green spaces contribute to localized AMR hotspots, acting as potential reservoirs of resistant and potentially pathogenic Enterococcus spp. These findings highlight the importance of One Health strategies for urban sanitation and AMR surveillance. Full article

Agroindustrial residues represent an abundant and underutilized source of carbon-rich materials for environmental remediation. In this study, annatto processing waste (Bixa orellana), a largely unexplored lignocellulosic by-product generated during pigment extraction, was converted into hydrochar via hydrothermal carbonization at 200 °C for 3 h. The resulting hydrochar (HC-AW) exhibited a predominantly amorphous carbon structure with retained oxygen-containing surface functionalities, and a solid yield of 44%, indicating efficient biomass conversion under subcritical conditions. Adsorption performance toward tetracycline was evaluated through pH-dependent experiments, kinetic modeling, equilibrium isotherms, and thermodynamic analysis. Maximum adsorption occurred under near-neutral conditions (pH ≈ 7), consistent with the interplay between tetracycline speciation and the hydrochar surface charge (pH_PZC ≈ 6.3), highlighting its potential applicability under realistic water treatment conditions without pH adjustment. Kinetic data were well described by the pseudo-second-order model, while equilibrium results were best fitted by the Langmuir model, with a maximum adsorption capacity of 14.94 mg g⁻¹ at 30 °C. Thermodynamic analysis indicated a spontaneous and slightly endothermic adsorption process. Overall, the results highlight the potential of annatto-derived hydrochar as a low-cost adsorbent and provide insight into the relationship between surface properties and adsorption behavior governing antibiotic removal from aqueous systems. Full article

Background: Ceftobiprole is an advanced-generation cephalosporin approved in Europe in 2013 for various indications, and in the United States (US) in 2024 for community-acquired bacterial pneumonia (CABP), acute bacterial skin and skin structure infections, and Staphylococcus aureus bacteremia, including right-sided endocarditis. Methods: The in vitro activity of ceftobiprole and comparators was evaluated against 2793 Streptococcus pneumoniae causing lower respiratory tract infections in 32 US sites (2016–2020), including against subsets from various geographic regions, resistance phenotypes and prevalent serotypes. Results: Ceftobiprole inhibited 99.5% of all S. pneumoniae at the MIC of ≤0.5 mg/L (MIC_50/90, 0.015/0.25 mg/L). Susceptibilities of 98.2% to 100% were observed for ceftobiprole against isolates originating from each surveyed year or each US Census Division. Ceftobiprole retained activity against isolates resistant to macrolides (98.8%), tetracycline (98.2%), oral penicillin (95.4%), against multidrug-resistant isolates (97.0%), and various serotypes (93.8–100%). Ceftriaxone (97.4%) and amoxicillin–clavulanate (95.1%) also showed elevated susceptibilities overall, but inconsistent results and lower than those observed for ceftobiprole were noted against isolates with elevated penicillin MIC or specific serotypes (i.e., 19A). Conclusions: These in vitro results, coupled with documented clinical efficacy, indicate that ceftobiprole is a valuable option to treat CABP caused by S. pneumoniae in the US. Full article