Widespread antibiotic use in aquaculture has increased selective pressure on resident bacterial communities, accelerating the emergence of resistance in key pathogens and raising concerns for animal health, environmental microbiomes, and food-chain safety. Reducing dependence on therapeutic antimicrobials requires alternative strategies that remain effective under the processing and biosafety constraints of intensive production systems, where recurrent bacterial diseases continue to cause substantial economic losses. Live probiotics, currently the most extensively studied microbiome-based intervention, have practical limitations, including reduced viability during feed pelleting and extrusion, transient gut colonization, strain-specific host responses, biosafety concerns related to horizontal transfer of antimicrobial-resistance genes, and variable regulatory requirements across regions. Postbiotics, defined as preparations of non-viable microbial biomass, with or without metabolites, that confer a demonstrated health benefit in the target host, and paraprobiotics, which emphasize inactivated whole-cell preparations that preserve surface-associated microbial molecular patterns, may help address several of these constraints. These approaches offer improved compositional definition, greater feed-processing stability, and a potentially more favorable biosafety profile. Because they are non-viable, their anti-pathogen effects do not depend on growth or competitive colonization but may instead involve preformed antimicrobial compounds retained in some preparations, interference with pathogen attachment, modulation of the intestinal environment, reinforcement of barrier function, and stimulation of host immune responses. This review synthesizes current evidence on postbiotics and paraprobiotics in aquaculture, with emphasis on structural classification, pattern-recognition receptor signaling, intestinal barrier function, innate immune priming, encapsulation technologies, and translational readiness. Taken together, available evidence supports postbiotics and paraprobiotics as promising, but not yet fully characterized, alternatives to live probiotics within antibiotic-reduction strategies for aquaculture. Progress toward commercial application will depend on resolving key questions related to dose–response relationships, processing stability in formulated feeds, and species-specific efficacy.
The rise in carbapenem resistance is well documented, but a less conspicuous trend has received far less attention: the gradual upward shift in minimum inhibitory concentration (MIC) values among isolates that remain phenotypically “susceptible.” We propose the term carbapenem floor for this phenomenon: an intermediate zone in which standard dosing regimens become progressively less reliable at achieving target exposure, yet which remains invisible to breakpoint-based surveillance; we present this as a hypothesis-generating framework consistent with existing pharmacokinetic and epidemiological evidence rather than as an empirically established trend, since no systematic longitudinal quantification of carbapenem MIC drift has yet been undertaken. Because carbapenems exhibit time-dependent killing and their pharmacokinetic/pharmacodynamic (PK/PD) target has MIC as its denominator, even a shift within the susceptible range can substantially reduce target attainment; augmented renal clearance in critically ill patients deepens this erosion. This review integrates resistance surveillance evidence with PK/PD principles to evaluate prolonged infusion, loading doses, therapeutic drug monitoring (TDM), and empirical protocols derived from population pharmacokinetic models and local MIC distributions, examining for each the evidence and the practical constraints. We also consider the reverse relationship: failure to attain PK/PD targets appears to select for elevated MICs, suggesting that dosing practice may contribute to resistance selection and potentially influence resistance epidemiology, not only respond to it. Extending antibiogram reporting to include MIC distributions, and translating those data into dosing protocols through antimicrobial stewardship, is a feasible priority where TDM infrastructure is limited.
The treatment of infective endocarditis (IE) in patients who inject drugs (PWID) is complex and challenging. These patients face stigma in the healthcare system, as well as higher mortality, longer length of hospital stay, higher rates of recurrent infections, and lower likelihood of antibiotic completion. Standard treatment for IE involves several weeks of antibiotics. For PWID, these prolonged courses often mean intravenous antibiotics administered in the inpatient setting for at least 4 to 6 weeks, which increases both healthcare costs and the risk of patient-directed discharge against medical advice. Effective treatment of IE in PWID involves a combination of addiction management and appropriate antibiotic therapy. To promote rational use of healthcare resources and optimize antibiotic stewardship, novel approaches to antibiotic therapy must be utilized. This review discusses evidence supporting treatment strategies outside of the inpatient hospital setting, including outpatient parenteral antibiotic therapy (OPAT), long-acting lipoglycopeptides, and oral antibiotic therapy for the treatment of endocarditis. Optimal treatment of IE in PWID involves support from a multidisciplinary healthcare team, management of substance use disorder, and effective antibiotic therapy.
Background/Objectives: Skin and soft tissue infections (SSTIs) remain a major clinical challenge due to the increasing prevalence of antimicrobial resistance and biofilm-associated pathogens. Conventional antibiotics are often limited by reduced efficacy, recurrent infections, and disruption of the resident skin microbiota. Consequently, bacteriocins have emerged as promising alternative or adjunctive antimicrobial agents for the treatment of skin and wound infections. Methods: A literature review was conducted using the PubMed, Scopus, and Web of Science databases. Experimental in vitro, ex vivo, and in vivo studies investigating bacteriocins in skin and wound infection models were analyzed, with a focus on antimicrobial activity, antibiofilm efficacy, activity against antimicrobial-resistant pathogens, and formulation strategies designed to improve therapeutic performance. Results: Available evidence demonstrates that numerous bacteriocins exhibit potent antimicrobial activity against clinically relevant skin-associated pathogens, particularly Staphylococcus aureus, including methicillin-resistant strains (MRSA). Several bacteriocins also showed significant antibiofilm properties and synergistic interactions with conventional antibiotics, resulting in enhanced bacterial eradication and reduced risk of resistance development. Experimental infection models further support their therapeutic potential in wound-associated infections. Additionally, advanced delivery platforms, including hydrogels, wound dressings, nanofibers, and lipid-based nanoparticles, improved peptide stability, sustained release, and local antimicrobial efficacy. Conclusions: Bacteriocins are promising candidates for the prevention and treatment of skin and wound infections due to their antimicrobial and antibiofilm activity, low propensity for resistance development, and suitability for topical administration. However, further studies addressing formulation optimization, safety, pharmacokinetics, and clinical validation are required before bacteriocin-based therapies can enter routine clinical practice.
The rise of multidrug-resistant (MDR) pathogens in the pediatric population represents a significant global health challenge, compounded by a historically stagnant antibiotic pipeline for children. While several novel antibiotics have been approved for adults in recent decades, pediatric labeling is often deferred due to the complexities of developmental pharmacology and due to a certain precautionary prudence in introducing new drugs onto the market for this population. This review explores the landscape of the most recent antibiotics, including advanced cephalosporins (ceftaroline, cefiderocol, and ceftobiprole), novel beta-lactam/beta-lactamase inhibitor combinations (e.g., ceftazidime/avibactam, meropenem/vaborbactam), and long-acting lipoglycopeptides. We analyze their approval trials, pediatric-specific PK/PD profiles, and the balance between on-label use and evidence-based off-label prescriptions. Furthermore, we emphasize the role of antimicrobial stewardship through the “3 D’s” rule and the evolution of Therapeutic Drug Monitoring (TDM) from reactive safety controls to proactive, model-informed precision dosing (MIPD). Finally, we advocate for a multidisciplinary synergy between pediatricians and pharmacologists as the cornerstone for optimizing outcomes and preserving the efficacy of the future antibiotic pipeline.
Background/Objectives: The prescription of aerosolized antimicrobial agents for lower respiratory tract infections varies significantly among clinicians. This study investigated the practices and perceptions of clinicians regarding aerosolized antimicrobial therapy. Methods: A cross-sectional study was conducted among infectious diseases (ID) and critical care clinicians (physicians and clinical pharmacists) in eight acute care hospitals in Qatar using a validated and pretested self-administered online questionnaire. Data was collected between September and October 2025, and analyzed using the Statistical Package for the Social Sciences (SPSS). Results: The majority of the respondents were physicians (70.5%), and about one-third (31.8%) had more than 15 years of work experience. A vast majority (97.7%) had previously prescribed or recommended aerosolized antimicrobial agents. Some respondents (34.1%) reported using aerosolized antimicrobial agents at least once every three months. The indications for aerosolized antimicrobial prescribing were for the treatment of bacterial infections (86.4%) and prophylaxis against bacterial infections (38.6%). Aerosolized antimicrobials were used for the treatment of ventilator-associated pneumonia (68.2%), cystic fibrosis (61.4%) and ventilator-associated tracheobronchitis (34.1%). Gentamicin (88.6%) and colistin (72.7%) were the most frequently used aerosolized antimicrobial agents. The majority (88.6%) of the respondents combined aerosolized antimicrobial agents with systemic antimicrobial agents, 65.9% of whom combined different antimicrobials for aerosolized and systemic routes. Pseudomonas aeruginosa (97.7%) and Acinetobacter baumannii (56.8%) were the most common microorganisms treated with aerosolized antimicrobial agents. Most respondents (61.4%) did not provide pre-treatment prior to aerosolized antimicrobial therapy. However, 38.6% used bronchodilators for pre-treatment. Bronchospasm (79.5%) and hypoxemia (20.5%) were the adverse effects reported by the respondents. Some respondents (40.9%) strongly agreed/agreed that aerosolized antimicrobial therapy improves clinical and microbial cure rates. While 81.8% strongly agreed/agreed that aerosolized antimicrobial therapy reduces systemic toxicity. Practices and perceptions varied significantly between ID and critical care specialties, and between physicians and pharmacists. Conclusions: Clinicians need training on aerosolized antimicrobial therapy for lower respiratory tract infections. Immunosuppression, renal function and infections due to multidrug-resistant organisms were reported by clinicians as factors that influenced their decision to use aerosolized antimicrobial therapy. A protocol for the administration of aerosolized antimicrobial therapy is recommended.
Background: Porphyromonas gingivalis is a Gram-negative, anaerobic keystone pathogen strongly implicated in the pathogenesis of periodontitis. Its pathogenicity is mediated through virulence factors, such as lipopolysaccharides (PG-LPS), which have been reported to display conflicting results regarding structural composition and immunogenicity. Objectives: This scoping review investigates how PG-LPS modulates host immunity and contributes to advanced periodontitis, with emphasis on its structural composition, divergent immunogenic properties, and the possible regulatory factors underlying these observations. Furthermore, PG-LPS interactions with periodontal tissues and associations with outer membrane vesicles (OMV) are examined. Materials and Methods: A structured literature search was conducted in PubMed following the PRISMA-ScR guidelines and PCC frameworks. Results: Structural heterogeneity, especially within the lipid A moiety of PG-LPS, accounts for previously inconsistent findings regarding its immunogenicity. Minor alterations in lipid A composition through enzymatic dephosphorylation or deacylation profoundly affect Toll-like receptor (TLR) engagement, antimicrobial resistance, and cytokine induction, and contribute to the biogenesis of OMVs. Environmental factors such as hemin availability and temperature influence enzymatic activity, resulting in lipid A isoforms that act as TLR4 agonists, antagonists, or remain immunologically inert. This structural plasticity mediates dynamic immune modulation that fosters polymicrobial dysbiosis and perpetuates non-resolving inflammation, leading to progressive tissue destruction, while concurrently contributing to the systemic inflammatory burden. Conclusions: Lipid A heterogeneity represents a central adaptive strategy potentially linking environmental cues and the bioenergetic status of P. gingivalis to immunomodulative properties. Verification of in vivo lipid A structural shifts in clinical isolates could inform novel therapeutic approaches targeting P. gingivalis-mediated inflammation.
Background/Objectives: Infectious keratitis and eye injuries, despite being well-recognized ophthalmological diseases, continue to pose diagnostic and therapeutic challenges in clinical practice; therefore, this study was conducted to assess the salient features of care provided by Spanish ophthalmologists working in emergency and ocular surface consultations to patients presenting with keratitis and ocular trauma. Methods: Nationwide cross-sectional survey with the participation of 100 ophthalmologists, including 50 ophthalmologists in emergency care and 50 ocular surface specialists. The study questionnaire assessed diagnostic approaches, treatment strategies, and factors influencing therapeutic decision making. Results: The mean age of participants (51% women) was 37.9 years, with 10.2 years of professional activity. External eye examination, slit lamp examination, fluorescein staining, computed tomography (CT) in penetrating injuries, and microbiological cultures in corneal ulcers were rated as important diagnostic methods. Topical antibiotics were especially recommended for keratitis in general (mean 80.6%) and for contact lens-related keratitis (85.6%). The use of antiseptics was limited. Topical corticosteroids were most commonly selected for viral keratitis with stromal and endothelial involvement (between 24.3% and 50.4%); chlorhexidine (52.0%) and propamidine (26.8%) for Acanthamoeba keratitis; re-epithelizing compounds (20.4%) and artificial tears (29.1%) for actinic keratitis; and topical antifungals for fungal keratitis (77%). Conclusions: This study highlights a limited availability of some specific diagnostic methods and an extensive use of topical antibiotics in the management of keratitis and ocular surface injuries, with relatively limited use of antiseptics. Areas of improvement in therapeutic approach would be awareness of a potential overuse of topical antibiotics with the consequences of increase in antimicrobial resistance.
Antimicrobial peptides (AMPs) are increasingly regarded as next-generation antimicrobial agents because of their broad-spectrum activity, rapid killing, antibiofilm potential, immunomodulatory properties, and mechanisms of action that differ from those of many conventional antibiotics. Despite these advantages, their clinical translation remains limited by proteolytic instability, hemolysis or cytotoxicity, poor pharmacokinetics, salt and serum sensitivity, production costs, and delivery challenges. The AMP field is therefore shifting from natural peptide discovery toward integrated engineering pipelines that combine rational peptide modification, biomaterial-based delivery, high-throughput screening, and artificial intelligence (AI), particularly machine learning (ML) and deep learning approaches. Chemical and structural modifications, including D-amino acid substitution, N-glycine substitution, cyclization, lipidation, PEGylation, terminal amidation, hydrocarbon stapling, hybridization, sequence truncation, metal coordination, and biomaterial immobilization, are being used to improve stability, potency, selectivity, antibiofilm activity, and tissue localization. In parallel, AI-guided approaches, including ML, deep learning, and generative modeling, enable large-scale exploration of diverse peptide sources, including microbiomes and extinct proteomes, to entirely new sequences, while supporting optimization of potency, selectivity, stability, toxicity, and synthesizability. This focused review summarizes recent advances in AMP engineering, biomaterial-assisted delivery, and AI-guided discovery for biofilm-associated infections in the context of antimicrobial resistance.
Background/Objectives: Serratia marcescens is an opportunistic pathogen that causes severe hospital-acquired infections, notable for its biofilm formation abilities and development of extensive antibiotic resistance. Here, we aim to evaluate the efficacy of bacteriophages, antibiotics, and antimicrobial peptides (BAP), alone and in combination, against fourteen multidrug-resistant (MDR) S. marcescens isolates sourced from hospitals and other environmental settings. Methods: S. marcescens was grown planktonically or in surface-associated biofilms, and biofilm biomass was measured via changes in absorbance and colony-forming units or live/death staining. Results: Combining bacteriophage with a low-dose cocktail of penicillin–streptomycin, kanamycin, and ciprofloxacin enhanced antimicrobial activity compared with antibiotics alone. Across the isolate panel, responses to BAP treatment varied according to determined antibiotic resistance profiles. The highly resistant AR-0517 isolate was selected for detailed mature biofilm analysis, where the BAP treatment reduced biofilm biomass by 97.8% and recoverable bacteria by 99.99%. Microscopy and viability assays further confirmed extensive biofilm disruption and bacterial killing. Conclusions: These findings demonstrate that simultaneous targeting of multiple bacterial pathways can enhance antimicrobial activity against MDR S. marcescens in vitro and support further evaluation of BAP as a potential strategy for biofilm-associated infections.
Background/Objectives: Antimicrobial resistance (AMR) and virulence represent co-evolving dimensions of microbial pathogenic potential whose ecological organization in building-scale wastewater systems remains poorly understood. Methods: Using shotgun metagenomic sequencing, we characterized the temporal dynamics and ecological associations of antimicrobial resistance genes (ARGs) and virulence factors (VFs) in 12 wastewater grab samples (2 per semester) collected from a university residence hall designated for COVID-19 quarantine between 2021 and 2023. Results: The wastewater microbiome was anchored by a stable core of gut-associated anaerobic bacteria, with community composition exhibiting significant Spring-versus-Fall structuring and a year × semester interaction that explained 60% of the community variation. A marked shift toward opportunistic taxa, particularly Acinetobacter, during Fall 2023 represented the most pronounced temporal perturbation. Total ARG abundance remained stable across semesters, while resistome composition shifted significantly, indicating that temporal dynamics were driven by compositional turnover rather than changes in overall resistance burden. VF functional categories were broadly conserved across sampling periods, consistent with their structural embedding within the persistent fecal core microbiome. Correlation and network analyses revealed modular ecological coupling between resistance and virulence functional categories, with metal/co-resistance and fosfomycin classes showing the strongest associations with virulence functions. At the community level, a Benjamini–Hochberg–corrected co-occurrence network resolved into taxa-anchored resistance modules and separate virulence-function clusters, with Acinetobacter and fluoroquinolone resistance as the principal connectors. Conclusions: These findings indicate that building-scale wastewater metagenomics can capture ecologically structured functional gene dynamics, highlighting its potential as a surveillance tool for monitoring AMR and virulence in built environments.
Background: Adults who undergo blood-culture sampling in the emergency department (ED) may be discharged before results are finalized and later found bacteremic. Factors identifying which patients require readmission are not well defined. We sought predictors of return and hospitalization available at the index ED visit. Methods: In this retrospective study at a 1000-bed university-affiliated hospital (September 2021–March 2026), we included adults discharged from the ED with a positive blood culture identified post-discharge. The primary outcome was ED return with hospitalization within 30 days. Multivariable logistic regression was restricted to variables available at the index ED visit. Results: Of 197 eligible patients, 16 were excluded, leaving 181 analyzed: 78 (43.1%) were managed as outpatients, 36 (19.9%) returned and were re-discharged, and 67 (37.0%) returned and were hospitalized. Median age was 73 (IQR 61–83) years and 105 (58.0%) were male. Index-visit vital signs and laboratory values did not differ across trajectories. The only independent predictor of return and hospitalization was a non-UTI working discharge diagnosis (aOR 2.53, 95% CI 1.3–5.0). Creatinine ≥ 2 mg/dL (aOR 2.65, 95% CI 0.9–7.5) and previous hospitalization within 6 months (aOR 1.82, 95% CI 0.8–4.1) were significant per univariate analysis but attenuated after adjustment, and age was not predictive. Enterobacterales predominated (n = 111, 61.3%). All nine endovascular-infection cases were hospitalized. Overall mortality was 1.1% (2/181). Conclusions: Post-discharge bacteremia carried low mortality but frequent ED return and hospitalization. A non-UTI working diagnosis independently identified a higher-risk minority; renal impairment and recent hospitalization were supportive but non-independent markers.
Uropathogenic Escherichia coli (UPEC) remains the principal driver of urinary tract infections (UTIs), utilizing sophisticated immunoevasive strategies that consistently outmaneuver host defenses and conventional clinical management. This review synthesizes current evidence highlighting the development of recurrent UTIs (rUTIs). Particular emphasis is given to the transition of UPEC into intracellular bacterial communities (IBCs) and quiescent intracellular reservoirs (QIRs)—survival phenomena primarily characterized across specialized mammalian and cellular models. By highlighting the translational evidence gaps surrounding these intracellular sanctuaries, and the challenge of directly extrapolating these model-derived dynamics to human recurrent UTIs (rUTIs), alongside the role of extra-urinary niches, we provide a comprehensive view of the mechanisms driving recurrence. A critical assessment of the UPEC virulence arsenal, involving molecular mechanisms that regulate fimbrial phase variation resulting in evading host immune surveillance, to specialized adhesins, like FimH, which tightly bind uroplakin receptors, triggering host actin rearrangements via rho-GTPase signaling and facilitating bacterial internalization, is also addressed. Additionally, we integrate the roles of cytotoxic necrotizing factor-1 (CNF1) and hemolysin A (HlyA) in promoting cytosolic escape, host cell survival, and long-term persistence. Finally, this review presents a multidisciplinary framework evaluating next-generation non-antibiotic strategies, including bacteriophage therapy, vaccines, phytotherapy, probiotics, and estrogen therapy. By critically assessing their efficacy and clinical maturity across a spectrum of preclinical models and human trials, we evaluate the potential to navigate translational limitations to effectively disrupt the infection cycle.
Background/Objectives: The increasing prevalence of antimicrobial resistance has reduced the effectiveness of conventional antibiotics, highlighting the need for alternative or adjunct antimicrobial agents. This study aimed to investigate the antibacterial, synergistic, and antibiofilm activities of Liquidambar orientalis Mill. essential oil against clinically relevant bacterial pathogens, using 24 bacterial strains representing 12 bacterial species. Methods: The volatile constituents of L. orientalis essential oil obtained by hydrodistillation of storax balsam were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). Antibacterial activity was evaluated using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), disk diffusion, and agar well diffusion assays against a panel of Gram-positive and Gram-negative bacterial pathogens. Synergistic interactions with erythromycin, amoxicillin, gentamicin, and enrofloxacin were assessed using fractional inhibitory concentration index (FICI) analysis. Antibiofilm activity was also evaluated against representative biofilm-forming strains. Results: A total of 90 volatile constituents were identified by GC-MS, of which styrene was the most abundant (68.6%), followed by (E)-ethyl cinnamate (6.8%), α-pinene (5.9%), and β-pinene (2.9%). The essential oil exhibited broad-spectrum antibacterial activity, with an overall inhibition rate of 60.4%. Activity was higher against Gram-positive (77.77%) than Gram-negative (73.33%) bacteria. MIC and MBC values ranged from 15.62 to 250 µg/mL and 31.25 to 250 µg/mL, respectively. FICI analysis revealed strain- and antibiotic-dependent interactions, ranging from synergistic to antagonistic effects. Variable antibiofilm activity was observed, with the strongest inhibition against Brucella melitensis and the weakest against Pseudomonas aeruginosa. No significant differences in MIC or MBC values were observed between bacterial groups (p > 0.05). Conclusions: L. orientalis essential oil demonstrated in vitro antibacterial activity against several clinically relevant pathogens, with particularly notable activity against B. melitensis. The essential oil also showed synergistic interactions with selected antibiotics and variable antibiofilm effects. These findings suggest that L. orientalis essential oil may have potential as an antibacterial agent or adjunct to antibiotic therapy; however, further in vivo and clinical studies are required to confirm its therapeutic applicability.
Background/Objectives: Wastewater-based epidemiology (WBE) has emerged as a valuable One Health approach for monitoring antimicrobial resistance (AMR) at the population level. Although quantitative PCR (qPCR) and shotgun (SG) metagenomics are widely used for wastewater surveillance, studies integrating these complementary approaches remain limited. This study aimed to investigate the occurrence, seasonal dynamics, and diversity of antimicrobial resistance genes (ARGs) in municipal wastewater from Central Italy by combining targeted qPCR and SG metagenomic sequencing. Methods: Influent wastewater samples were collected monthly from eight municipal wastewater treatment plants in Central Italy between April 2025 and March 2026. Clinically relevant antimicrobial resistance genes were quantified by quantitative real-time PCR, while SG metagenomic sequencing was used to characterize resistome composition, resistance gene families, and ARG sequence diversity using bioinformatic pipelines. Results: All investigated ARGs were detected in every sample. Significant seasonal variation was observed for all investigated markers, including qnrS, blaKPC, blaCTX-M and intI1. Metagenomic analysis revealed broadly similar resistome profiles across sampling sites and time points, dominated by resistance genes to macrolide–lincosamide–streptogramin, aminoglycosides, β-lactams, and fluoroquinolones. High sequence diversity was observed within the dominant ARG families, highlighting the complementary value of SG metagenomics for comprehensive resistome characterization. Conclusions: The integration of targeted qPCR and SG metagenomics provided a comprehensive characterization of antimicrobial resistance in municipal wastewater. While qPCR enabled sensitive quantification of clinically relevant ARGs and revealed seasonal trends, metagenomics expanded resistome characterization by identifying dominant resistance classes, gene families, and sequence variants. These findings support the implementation of integrated molecular approaches for routine wastewater-based AMR surveillance within a One Health framework.
Background/Objectives: Colistin is a last-resort agent against multidrug-resistant Gram-negative infections and is administered predominantly to complex, comorbid inpatients in whom mortality is high. We aimed to identify independent baseline predictors of in-hospital mortality in colistin-treated patients and to characterize temporal changes in mortality over 15 years. Methods: We conducted a retrospective cohort study of 1225 consecutive patients receiving systemic colistin between November 2009 and November 2024 at Parhon Hospital, a tertiary urology–nephrology center in Iași, Romania; independent predictors of death were identified using multivariable logistic regression restricted to variables fixed at the time of colistin initiation, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI). Results: Patients were predominantly male (60.2%), with a mean age of 65.1 ± 14.4 years; 85.6% were admitted to urology or nephrology. In-hospital mortality was 27.6%. Mortality was independently associated with acute kidney injury (aOR 3.72, 95% CI 2.76–5.01), sepsis (aOR 2.79, 95% CI 2.11–3.70), emergency admission (aOR 1.91, 95% CI 1.40–2.61), Charlson comorbidity index (aOR 1.13 per point, 95% CI 1.05–1.22), and older age (aOR 1.03 per year, 95% CI 1.02–1.04); sex was not associated. Crude mortality increased across the study period (odds ratio 1.16 per year, 95% CI 1.13–1.20) and remained elevated after adjustment for case-mix (adjusted odds ratio 1.13 per year, 95% CI 1.09–1.17). Conclusions: Acute kidney injury, sepsis, emergency admission, comorbidity burden, and age were independently associated with in-hospital death. Mortality rose progressively over 15 years, only partly explained by an increasingly severe case-mix, supporting early risk stratification of colistin recipients.
Background/Objectives: The application of organic soil amendments constitutes an important source of antibiotic residues in agricultural soils. However, studies have mainly focused on a few parent tetracyclines, whereas information on their transformation products (TPs) in organic amendments remains scarce. Therefore, this study assessed the occurrence and environmental risk of six tetracyclines and seven TPs in organic amendments. Methods: Processed livestock manures applied in the European Union (horse, poultry, and bovine manure), as well as fresh and treated sewage sludge, were analyzed using matrix solid-phase dispersion (MSPD) combined with online SPE-LC-MS/MS. Environmental risk was assessed using risk quotients (RQs) based on predicted environmental concentrations in soil (PECsoil) calculated from the maximum measured concentrations and predicted no-effect concentrations in soil (PNECsoil) obtained either directly from terrestrial ecotoxicity data or derived from aquatic ecotoxicity data using the equilibrium partitioning method and soil-water distribution coefficients. Results: Tetracyclines and their TPs were widely detected in both sample types, although concentrations varied according to matrix type and treatment. Overall, sludge showed higher detection frequencies and concentrations than manure. Doxycycline and tetracycline were the predominant parent compounds, reaching concentrations up to 2838 ng g−1 dry weight (dw) in manure and 2892 ng g−1 dw in sludge. Epimerized TPs were frequently detected and sometimes exceeded the concentrations of their parent compounds, especially epitetracycline and epioxytetracycline. Among the sludge types and treatment conditions investigated, anaerobically digested sludge showed the highest tetracycline concentrations, whereas the composted sludge sample presented the lowest concentrations. Individual RQs indicated insignificant to low ecotoxicological risk, whereas cumulative RQ (ΣRQ) values, used as conservative estimates of co-exposure to all evaluated tetracyclines and their TPs, fell within the medium-risk category for bovine manure and anaerobically digested sludge, with the composted sludge sample showing the lowest ΣRQ. Conclusions: These findings highlight the importance of including TPs in environmental monitoring and the differences in tetracycline occurrence and environmental risk to soil among the processed manure types and sludge treatment conditions investigated.
Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a major nosocomial pathogen; bacteriophage therapy is a promising alternative, but its principal challenge is the rapid emergence of phage resistance. Cocktails counter this yet they are usually assembled by simply pooling phages active against the bacterium, not designed against the resistant mutants that arise. Methods: Next evolutionary phage typing (NEPT) addresses this by inducing resistance to a primary phage and then selecting secondary phages that lyse the resulting resistant mutant. Because choosing effective secondary phages still relies on qualitative visual reading of plaques (size and clarity), this study aimed to identify a rapid quantitative criterion. Results: Using the clinical strain CRAB 43895 and primary phage ϕ8, we obtained 65 NEPT-derived secondary phages that lyse the ϕ8-resistant mutant (ϕ8R) and combined four quantitative indicators—relative bacterial growth, lytic capability, coverage rate, and plaque morphology—with binary logistic regression to predict effective inhibition by the ϕ8 + secondary-phage cocktail (96-h OD600 < 0.1). Of the four, only lytic capability (the titer after 3 h of co-culture) independently predicted effective inhibition (ROC AUC = 0.76; at ≥107 plaque-forming units (PFU)/mL, sensitivity 0.83, specificity 0.69). Conclusions: Lytic capability thus provides a rapid (~8–12 h), quantitative criterion for selecting effective secondary phages within the NEPT framework, improving on conventional qualitative typing.
Background/Objectives: This prospective cross-sectional study quantified veterinary antimicrobial residues in soils from 27 commercial beef feedlots across multiple regions of Argentina and production scales. Methods: Using a validated Ultra-Fast Liquid Chromatography–tandem mass spectrometry (UFLC-MS/MS) method, we measured 15 target antimicrobials in pooled corral soil samples. Results: Monensin was detected in all feedlots and showed the highest detection frequency and widest concentration range; peak concentrations exceeded 15,000 ppb in some sites. Oxytetracycline presented pronounced, site-specific peaks (approaching 14,000 ppb), consistent with its strong adsorption to soil organic matter and limited biodegradation. These results indicate localised hotspots of antimicrobial loading in feedlot environments. These elevated concentrations signify substantial antimicrobial loading in confined animal environments and potential hotspots for environmental selection pressure. Compounds absent from farm treatment records were detected in 40.7% of feedlots, correlating with antimicrobial residues not matching available AMU records, including oxytetracycline, tulathromycin, cefquinome, enrofloxacin, and ciprofloxacin among others. Multiple non-exclusive explanations are plausible (historical persistence, manure redistribution, incomplete records, off-label use, or cross-contamination). The detection of critically important antimicrobials (e.g., fluoroquinolones and advanced cephalosporins) in soils raises One Health concerns about environmental selection pressure and the potential dissemination of resistance determinants. Conclusions: These findings underscore gaps in stewardship and the need for integrated environmental monitoring and improved antimicrobial usage traceability. These data provide a baseline for ecological risk assessment and resistome studies and can inform evidence-based policy and stewardship interventions in Argentine feedlot systems.
Background/Objectives: Bacillus spp. are often isolated from airborne microbiota. Five Bacillus strains (AD12–16) isolated from dust during a sandstorm in Kuwait were characterized for their potential to produce antimicrobial compounds, biosurfactants and siderophores by genotypic and phenotypic approaches. Methods: Whole-genome sequencing was performed, and biosynthetic gene clusters (BGCs) were predicted using antiSMASH. Antimicrobial activities were determined by agar-well diffusion assays. Siderophore and biosurfactant production were determined by Arnow’s and drop-collapse assays, respectively. The active metabolites were separated, fractionated, and analyzed by minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and LC–MS/MS. Results: Genome mining identified many BGCs associated with known secondary metabolites such as bacillibactin and bacilysin, as well as a number of unassigned clusters. The isolates exhibited distinct antimicrobial profiles, with Bacillus subtilis AD16 displaying the highest antimicrobial activity against multidrug-resistant pathogens. Biosurfactant- and siderophore-associated activities varied among the isolates. Active fractions demonstrated bactericidal activity, while LC–MS/MS analysis revealed molecular features tentatively assigned to siderophore- and lipopeptide-associated metabolite classes based on accurate mass and MS/MS fragmentation patterns. Conclusions: The combination of unassigned BGCs, antimicrobial activity, and incompletely characterized molecular features highlights unexplored biosynthetic potential in sandstorm-derived Bacillus. Further purification and structural characterization are required to establish the identities and biological functions of the active metabolites.
