Global burden of bacterial antimicrobial resistance 1990-2021: a systematic analysis with forecasts to 2050

Target-Guided Design and Synthesis of Aryl-Functionalized Promysalin Analogs

The development of new narrow-spectrum antibiotics is a promising approach to combat antibiotic resistance. Promysalin, a secondary metabolite isolated from Pseudomonas putida, exhibits potent species-specific inhibition of the pathogen P. aeruginosa (IC50 21 nM). Herein, the total synthesis and stereochemical assignment of promysalin, structure-activity relationship studies, and the identification of its molecular target, succinate dehydrogenase, are previously reported by the group. These findings enable computational studies of promysalin's interactions with succinate dehydrogenase, revealing a novel binding site region primed for π-π stacking interactions with a nearby tryptophan residue. It is hypothesized that new aromatic analogs of promysalin can target this beneficial interaction, potentially leading to more potent inhibitors of P. aeruginosa growth. Herein, the in silico design of these analogs, a scalable and general synthetic route to access them, and characterization of their activity against a panel of clinically relevant P. aeruginosa strains are reported.

Photocatalysis and Photodynamic Therapy in Diabetic Foot Ulcers (DFUs) Care: A Novel Approach to Infection Control and Tissue Regeneration

Photocatalysis and photodynamic therapy have been increasingly used in the management of diabetic foot ulcers (DFUs), and their integration into increasingly innovative treatment protocols enables effective infection control. Advanced techniques such as antibacterial photodynamic therapy (aPDT), liposomal photocatalytic carriers, nanoparticles, and nanomotors-used alone, in combination, or with the addition of antibiotics, lysozyme, or phage enzymes-offer promising solutions for wound treatment. These approaches are particularly effective even in the presence of comorbidities such as angiopathies, neuropathies, and immune system disorders, which are common among diabetic patients. Notably, the use of combination therapies holds great potential for addressing challenges within diabetic foot ulcers, including hypoxia, poor circulation, high glucose levels, increased oxidative stress, and rapid biofilm formation-factors that significantly hinder wound healing in diabetic patients. The integration of modern therapeutic strategies is essential for effective clinical practice, starting with halting infection progression, ensuring its effective eradication, and promoting proper tissue regeneration, especially considering that, according to the WHO, 830 million people worldwide suffer from diabetes.

Prospective Genomic Surveillance of Severe Febrile Illness in Tanzanian Children Identifies High Mortality and Resistance to First-Line Antibiotics in Bloodstream Infections

We evaluated the prevalence, pathogen profile, and antimicrobial resistance (AMR) patterns of bloodstream infections (BSIs) among 392 children with severe febrile illness who presented (July 26, 2022-September 20, 2023) to a referral hospital in Tanzania. We identified a causative pathogen in 9.8% (n=38) of participants. Blood culture analysis confirmed BSI in 5.2% (n=20) of participants with a case fatality rate of 45%. Whole genome sequencing (WGS) of blood culture isolates identified gram-negative bacteria ( Escherichia coli, Klebsiella pneumoniae ) as the predominant pathogens, many exhibiting extended-spectrum beta-lactamase (ESBL) resistance genes (CTX-M-15, CTX-M-27), rendering them resistant to first-line antimicrobials. We also observed probable nosocomial transmission in ventilated patients based on phylogenetic analyses of tracheal aspirate isolates. There is an urgent need for enhanced AMR surveillance, empiric antibiotic regimens tailored to local AMR patterns, culture-independent diagnostics, and robust infection control practices in resource-limited settings to mitigate BSI-related mortality and minimize nosocomial transmission risk.

Funding

NIAID K23AI144029 (TBK), NIAID K23AI185326 (VTC), Chan Zuckerberg Biohub (JLD, CRL).

Article Summary Line

Genomic surveillance of severe febrile illness in Tanzanian children reveals high mortality rates and widespread resistance to first-line antibiotics, highlighting the urgent need for tailored treatments and enhanced antimicrobial resistance monitoring.

The rise and global spread of IMP carbapenemases (1996-2023): a genomic epidemiology study

Background

IMP carbapenemases confer extensive drug resistance and are increasingly noted worldwide. Despite this, little is known regarding the global epidemiology of IMP carbapenemases.

Methods

We comprehensively identified bla IMP genes in all publicly available bacterial genomes, then systematically analysed the distribution of variants across species, lineages, plasmids and mobile elements, examining patterns over time, across geographic regions and by source. Structural analysis of IMP variants was performed.

Findings

4,556 bla IMP -containing genomes were identified from 1996-2023, including 52 bla IMP variants across 93 bacterial species. Key variants ( bla IMP-1 , bla IMP-4 , bla IMP-7 , bla IMP-8 and bla IMP-13 ) achieved global endemicity, while bla IMP-26 and bla IMP-27 were regionally endemic in Southeast Asia and North America, respectively. bla IMP dissemination was driven by horizontal gene transfer, facilitating inter-species spread. Proliferation of multidrug-resistant Enterobacter hormaechei , Pseudomonas aeruginosa and Klebsiella pneumoniae lineages led to local outbreaks. Dereplication removed 3,175/4,556 (69.9%) genomes, indicating that most bla IMP -containing genomes were highly related. bla IMP variants were associated with mobile genetic element combinations including class 1 integrons and insertion sequences (99.7%), aiding mobilisation into ≥52 plasmid clusters, predominantly IncHI2A, IncN, IncL/M and IncC. Genomes of environmental and animal origin accounted for 10.0% and 1.1% of the dataset, respectively. Evidence of cross-source transmission was limited, with most spillover occurring between genomes of human and environmental origin. Structural analysis revealed a conserved carbapenemase structure (mean lDDT 0.977), with convergent missense mutations at seven catalytically relevant sites.

Interpretation

Global analysis enabled us to historically reconstruct the emergence and variant-specific epidemiologies of bla IMP carbapenemase genes. Intersecting mobile elements enabled bla IMP genes to spread across multiple plasmids and bacterial genera, facilitating global and multi-source spread within a One Health framework. Additionally, convergent evolutionary patterns indicate that IMP variants may continue evolving, potentially evading novel beta-lactam antimicrobial agents.

Funding

NHMRC EL1 (APP1176324) to N.M.; NHMRC PF (APP1117940) to A.Y.P.; NIH/NIAID R01AI175414 to A.G-S.

Research in context panel

Evidence before this study: Despite being a major cause of carbapenem resistance in Gram negative infections, little is known about the global epidemiology of IMP carbapenemases. IMP carbapenemases are metallo-beta-lactamases that were first identified in 1991 and have evolved into 96 different IMP variants. On May 21 2025, we searched all published reports available in PubMed using the terms "'IMP' and 'carbapenemase' genomics NOT (Review[Publication Type]) NOT (Case Reports[Publication Type]) NOT PCR" with no language restrictions and no publication date restrictions. We identified 223 articles, 62 and 121 of which reported single species or a single study centre/country, respectively. Only 6 articles employed genomics to examine multi-species and multi-geographical isolates, though this was in the context of carbapenem resistance more broadly rather than IMP carbapenemases specifically. The most relevant study included 38 globally distributed genomes across four species and tracked seven blaIMP variants across mobile genetic elements.Added value of this study: To our knowledge, this global characterisation provides the most comprehensive account of bla IMP carbapenemase gene epidemiology. To analyse the global distribution and diversity of bla IMP genes, we compiled all available public genome data resulting in a dataset of 4,646 genomes. This has allowed us to identify local, regional and international spread of bla IMP variants and determine the contributions of clonal expansion, plasmid proliferation and co-localised mobile genetic elements. We demonstrated that key bla IMP variants display global (IMP-1, IMP-4, IMP-7, IMP-8 and IMP-13) and regional (IMP-26 within Southeast Asia and IMP-27 within North America) endemicity and that these patterns have been previously unacknowledged, reframing the previous understanding that IMP carbapenemases were largely confined to the Asia-Pacific region. Our observation of convergent evolutionary patterns raise concern that IMP variants may continue to evolve, potentially evading new β-lactam antimicrobials. This analysis has revealed the under-recognised contribution IMP carbapenemases make to global carbapenem resistance. Implications of all the available evidence: These findings provide the first comprehensive atlas of bla IMP carbapenemase gene dissemination and underscore the silent global spread of IMP carbapenemases. We note the critical need for enhanced surveillance systems, particularly in low- and middle-income countries, that can detect complex plasmid-mediated and mobile genetic element-associated spread, as we noted with bla IMP carbapenemase genes. Moreover, our analyses show that systematic sampling across human, animal, and environmental reservoirs is crucial to address the One Health dimensions of emerging antimicrobial resistance threats. The study provides a framework for future interventions aimed at tracking and stopping the spread of IMP carbapenemases and calls for co-ordinated, real-time public health responses to this growing challenge.

Novel Antimicrobials from Computational Modelling and Drug Repositioning: Potential In Silico Strategies to Increase Therapeutic Arsenal Against Antimicrobial Resistance

Antimicrobial resistance (AMR) is one of the most significant public health threats today. The need for new antimicrobials against multidrug-resistant infections is growing. The development of computational models capable of predicting new drug-target interactions is an interesting strategy to reposition already known drugs into potential antimicrobials. The objective of this review was to compile the latest advances in the development of computational models capable of identifying drugs already registered by the Food and Drug Administration for other indications with potential capacity to be applied as antimicrobials. We present studies that apply in silico methods such as machine learning, molecular docking, molecular dynamics and deep learning. Some of these studies have in vitro/in vivo results that demonstrate the reliability of this computational methodology in terms of the identification of effective molecules and new targets of interest in the treatment of infections. In addition, we present the methods that are under development and their future prospects in terms of the search for new antimicrobials. We highlight the need to implement these strategies in the research of effective drugs in the treatment of infectious diseases and to continue to improve the available models and approaches to gain an advantage against the rapid emergence of AMR.

C-reactive protein point-of-care testing to guide antibiotic prescribing for respiratory tract infections

INTRODUCTION

Antimicrobial resistance is strongly correlated with the volume of antibiotics used. Most antibiotics are prescribed in primary care, mostly for respiratory tract infections (RTIs), and are often unneeded.

AREAS COVERED

The current knowledge regarding the use of C-reactive protein (CRP) rapid testing in primary care is outlined. A comprehensive literature search and narrative review of the evidence on CRP rapid testing for patients presenting with symptoms of RTIs was conducted to develop a holistic perspective on the subject. Relevant studies were identified through a PubMed search up to April 2025.

EXPERT OPINION

CRP testing is an effective, cost-efficient tool to reduce unnecessary antibiotic use for lower RTIs in primary care. This test should be included in guidelines and implemented when a clinician is uncertain about the prognosis of an infection. It should complement history taking and clinical examination before deciding to prescribe antibiotics, primarily to rule out serious infections, but should never be used as a standalone test. To tackle antimicrobial resistance, the reduction of unnecessary antibiotic use in acute RTIs is optimized with clear guidance, advanced communication training for clinicians, and delayed antibiotic prescribing strategies when applicable.

Amphiphilic dendrimer-assisted delivery of antisense nucleic acid mimics against E. coli

The rise in antimicrobial resistance and the consequent ineffectiveness of conventional antibiotics emphasise the need for novel therapeutic strategies. Antisense nucleic acid mimics (NAMs) are emerging as promising precision therapeutic agents, inhibiting specific genes through hybridisation with selected nucleic acid targets. However, delivering NAMs into bacteria remains a significant challenge. This study explores the use of poly(amidoamine) (PAMAM) amphiphilic dendrimers (ADs) as delivery vehicles for NAMs targeting the essential acpP gene in Escherichia coli. Two ADs bearing primary amine or tertiary amine terminals, 1a and 1b, were tested for their ability to permeabilise the bacterial envelope, facilitate NAM internalisation, and enhance NAM-based antibacterial activity. Physicochemical characterisation studies, flow cytometry measurements, fluorescence and electron microscopy imaging, bacterial viability assays, and an in vivo toxicity assessment using a greater wax moth (Galleria mellonella) model were conducted. Both ADs acted as permeabilisers of the bacterial envelope and assisted in NAM internalisation and antibacterial activity. The most effective formulation, 1b combined with the peptide nucleic acid (PNA)-based NAM, achieved an 8 log10 reduction in viable bacteria, with sustained activity up to 24 h against E. coli. In vivo, the most promising formulations showed no toxicity, with G. mellonella larvae maintaining overall health and no significant mortality detected for up to three days. These findings demonstrate that amphiphilic dendrimers can effectively deliver PNA-based NAMs, highlighting their potential as a novel strategy against antimicrobial-resistant pathogens.

Metaproteomics in the One Health framework for unraveling microbial effectors in microbiomes

One Health seeks to integrate and balance the health of humans, animals, and environmental systems, which are intricately linked through microbiomes. These microbial communities exchange microbes and genes, influencing not only human and animal health but also key environmental, agricultural, and biotechnological processes. Preventing the emergence of pathogens as well as monitoring and controlling the composition of microbiomes through microbial effectors including virulence factors, toxins, antibiotics, non-ribosomal peptides, and viruses holds transformative potential. However, the mechanisms by which these microbial effectors shape microbiomes and their broader functional consequences for host and ecosystem health remain poorly understood. Metaproteomics offers a novel methodological framework as it provides insights into microbial dynamics by quantifying microbial biomass composition, metabolic functions, and detecting effectors like viruses, antimicrobial resistance proteins, and non-ribosomal peptides. Here, we highlight the potential of metaproteomics in elucidating microbial effectors and their impact on microbiomes and discuss their potential for modulating microbiomes to foster desired functions.

Derivatization of pBACpAK entrapment vectors for enhanced mobile genetic element transposition detection in multidrug-resistant Escherichia coli

Aim. Antimicrobial resistance poses a critical global health threat, driven by the dissemination of resistance genes via mobile genetic elements (MGEs). This study aims to enhance the detection of MGE insertions in multidrug-resistant Escherichia coli by derivatizing the pBACpAK entrapment vector. Methods and results. Three derivatives were constructed with additional nucleotides upstream of the cI repressor gene, based on conserved regions identified from GenBank sequences containing known IS26 and IS1 insertions. Using colony PCR, intracellular transposition screening was performed on 194 tetracycline-resistant colonies from four E. coli ESI123 strains carrying different pBACpAK constructs. The derivatives showed increased MGE capture rates (10.7-73.1 %) compared to the WT vector (3.75%), identifying multiple MGEs, including the novel composite transposon Tn7824. Tn7824 harbours the bla OXA-181 carbapenem resistance gene and the qnrS1 quinolone resistance gene, highlighting the clinical relevance of these findings. Long-read sequencing of transposants confirmed the accuracy of MGE identification and structural characterization, which also revealed chromosomal integration events of the pBACpAK derivatives mediated by flanking insertion sequences. Conclusions. The modifications introduced in the pBACpAK derivatives could increase the detection of transposition events by alleviating spatial constraints, allowing for more robust MGE detection.

Trends in the global, regional, and national burden of cardiovascular diseases attributed to high systolic blood pressure from 1990 to 2021 and projections to 2045: a systematic analysis based on GBD 2021 data

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide, and high systolic blood pressure (HSBP) is considered among its most critical modifiable risk factors. This study analyzed the temporal trends of the global burden of CVD attributed to HSBP from 1990 to 2021, examined its relationships with age, period, and birth cohort, and projected future trends to 2045.

METHODS

The study employed a joinpoint regression model to evaluate the temporal trends of CVD burden attributed to HSBP from 1990 to 2021 and used an Age-Period-Cohort (APC) model to analyze the effects of age, period, and cohort. Additionally, a Bayesian Age-Period-Cohort (BAPC) model was applied to project the disease burden trends up to 2045.

RESULTS

From 1990 to 2021, the absolute number of deaths and DALYs (disability-adjusted life years) of CVD attributed to HSBP increased significantly. However, the age-standardized mortality rate (ASMR) and age-standardized DALY rate (ASDR) showed a consistent declining trend. The study highlights significant regional differences, with the disease burden increasing most markedly in regions with a middle Socio-Demographic Index (SDI) and decreasing most significantly in high SDI regions. Additionally, the study revealed gender differences, with the decline in ASMR and ASDR was more pronounced in females, while males exhibited a higher overall disease burden than females. Projections from the BAPC model indicate that from 2022 to 2045, the absolute number of deaths and DALYs will continue to rise, while ASMR and ASDR will decline further.

CONCLUSIONS

This study conducted a comprehensive analysis of CVD attributed to HSBP globally, highlighting significant sex, age, and regional differences in disease burden as well as their temporal trends. The findings underscore the importance of targeted prevention strategies, particularly for high-risk populations. This study provides valuable insights for policymakers to formulate effective interventions to reduce the global disease burden.

Evolutionary accumulation modeling in AMR: machine learning to infer and predict evolutionary dynamics of multi-drug resistance

Can we understand and predict the evolutionary pathways by which bacteria acquire multi-drug resistance (MDR)? These questions have substantial potential impact in basic biology and in applied approaches to address the global health challenge of antimicrobial resistance (AMR). In this minireview, we discuss how a class of machine-learning approaches called evolutionary accumulation modeling (EvAM) may help reveal these dynamics using genetic and/or phenotypic AMR data sets, without requiring longitudinal sampling. These approaches are well-established in cancer progression and evolutionary biology but currently less used in AMR research. We discuss how EvAM can learn the evolutionary pathways by which drug resistances and other AMR features (for example, mutations driving these resistances) are acquired as pathogens evolve, predict next evolutionary steps, identify influences between AMR features, and explore differences in MDR evolution between regions, demographics, and more. We demonstrate a case study from the literature on MDR evolution in Mycobacterium tuberculosis and discuss the strengths and weaknesses of these approaches, providing links to some approaches for implementation.

Phage therapy: A novel approach to combat drug-resistant pathogens

Antibiotic-resistant infections, such as those caused by the overuse of antibiotics, have greatly strained healthcare systems. Among them, drug-resistant bacteria ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are typical and common. Enterococcus faecalis and Escherichia coli are of equal concern. These pathogens often have higher pathogenicity than the same strains, and resistance has reduced treatment options, so new treatment options are needed to address these pathogens. This review analyzes recent studies related to phage therapy for the treatment of bacterial infections in various parts of the human body (e.g., alcoholic liver disease, skin, and soft tissues, respiratory tract, gastrointestinal tract, urinary system, etc.), to better understand the potential role of phage therapy as a non-antibiotic strategy for the treatment of infections caused by drug-resistant bacteria. In addition, this review introduces a series of products related to phage therapy and points out potential research directions for phage therapy in clinical applications. This paper elucidates the basic mechanism of human infection by some drug-resistant bacteria and the therapeutic effect of phage therapy against drug-resistant bacteria. It popularizes the understanding of phage therapy and provides a reference for research on its use for drug-resistant bacterial infections.

Worldwide burden and cross-regional health inequalities of high BMI-attributable colorectal cancer by gender from 1990 to 2021, with predictions through 2041

PURPOSE

To analyze the worldwide, regional, and national burden and trends of colorectal cancer (CRC) attributable to high body mass index (BMI) by gender from 1990 to 2021 and to forecast the burden through 2041.

METHODS

Data on deaths and disability-adjusted life years (DALYs) of CRC attributable to high BMI were obtained from the Global Burden of Disease (GBD) Study 2021. Disparities and trends in CRC due to high BMI burden were analyzed globally and regionally, with stratification by gender and age subgroups. An autoregressive integrated moving average (ARIMA) model was employed to project the future burden through 2041.

RESULTS

In 2021, the global age-standardized mortality rate (ASMR) and age-standardized DALYs rate (ASDR) of CRC attributable to high BMI were estimated at 1.17 [95% uncertainty interval (UI): 0.51 to 1.87] and 27.33 (95% UI: 11.80 to 43.37) per 100,000 population, respectively. Both metrics showed a modest increase from 1990 to 2021. During this period, the population attributable fraction (PAF) of CRC deaths due to high BMI increased steadily. Similarly, the PAF of CRC DALYs caused by high BMI also showed a continuous rise. High socio-demographic index (SDI) regions, Central Europe and countries such as Hungary and Slovakia, recorded the highest ASMR and ASDR in 2021. Projections indicate that the global ASMR will decrease by 1%, while the ASDR will increase by 4.23% by 2041.

CONCLUSION

The global burden of CRC attributable to high BMI remains substantial and is projected to persist, with considerable regional and national variability. These findings emphasize the need for targeted public health interventions and policies to address this preventable risk factor.

In Vitro Immune Response of Mononuclear Cells to Multidrug-Resistant Escherichia coli

Infections caused by multidrug-resistant organisms (MDRO) are linked to poor outcomes, particularly in patients with cirrhosis. The underlying mechanisms are not fully understood and may involve a different immune response against MDRO. This study aimed to compare the in vitro immune response between multidrug-resistant (MDR) Escherichia coli and antibiotic-susceptible E. coli strains. Surface protein extract and DNA extract were obtained from MDR E. coli (n = 6) and antibiotic-susceptible E. coli (n = 6) strains isolated from infected patients with cirrhosis. The extracts were used to stimulate in vitro peripheral blood mononuclear cells from healthy donors. After 48 h, cytokine levels (IFN-γ, IL-1β, IL-10, IL-12p70, MCP-1, IL-8, IL-6, MIP-1α, and MIP-1β) were measured. We observed no significant differences in cytokine production between MDR and susceptible strains. However, we identified notable interindividual variability in cytokine production for most of the cytokines studied. Only IFN-γ and IL-6 in surface extract and MCP-1 in DNA extract showed similar levels across all donors. We conclude that the cytokine profiles induced by MDR E. coli in vitro were similar to those in susceptible strains. These findings suggest that the poor prognosis associated with MDR E. coli infections is not due to a differential immune response but rather to other factors.

Heterogeneity in recombination rates and accessory gene co-occurrence distinguish Pseudomonas aeruginosa phylogroups

Pseudomonas aeruginosa (class Gammaproteobacteria) is a ubiquitous, ecologically widespread, and metabolically versatile species. It is also an opportunistic pathogen that causes a variety of chronic and acute infections in humans. Its ability to thrive in diverse environments and exhibit a wide range of phenotypes lies in part on its large gene pool, but the processes that govern inter-strain genomic variation remain unclear. Here, we aim to characterize the recombination features and accessory genome structure of P. aeruginosa using 840 globally distributed genome sequences. The species can be subdivided into five phylogenetic sequence clusters (corresponding to known phylogroups), two of which are most prominent. Notable epidemic clones are found in the two phylogroups: ST17, ST111, ST146, ST274, and ST395 in phylogroup 1, and ST235 and ST253 in phylogroup 2. The two phylogroups differ in the frequency and characteristics of homologous recombination in their core genomes, including the specific genes that most frequently recombine and the impact of recombination on sequence diversity. Each phylogroup's accessory genome is characterized by a unique gene pool, co-occurrence networks of shared genes, and anti-phage defense systems. Different pools of antimicrobial resistance and virulence genes exist in the two phylogroups and display dissimilar patterns of co-occurrence. Altogether, our results indicate that each phylogroup displays distinct histories and patterns of acquiring exogenous DNA, which may contribute in part to their predominance in the global population. Our study has important implications for understanding the genome dynamics, within-species heterogeneity, and clinically relevant traits of P. aeruginosa.

IMPORTANCE

The consummate opportunist Pseudomonas aeruginosa inhabits many nosocomial and non-clinical environments, posing a major health burden worldwide. Our study reveals phylogroup-specific differences in recombination features and co-occurrence networks of accessory genes within the species. This genomic variation partly explains its remarkable ability to exhibit diverse ecological and phenotypic traits, and thus contribute to circumventing clinical and public health intervention strategies to contain it. Our results may help inform efforts to control and prevent P. aeruginosa diseases, including managing transmission, therapeutic efforts, and pathogen circulation in non-clinical environmental reservoirs.

A disproportionality analysis of adverse events associated with ertapenem using the FAERS database from 2004 to 2024

Through an in-depth analysis of ertapenem-associated adverse events (AEs) in the FDA Adverse Event Reporting System (FAERS) database, this study provides a reference for monitoring and safety management of ertapenem. Data from the FAERS database from Q1 2004 to Q1 2024 were analyzed via four nonproportional analysis techniques, including the reporting odds ratio (ROR). Gender, age, and sensitivity analyses were conducted for a more detailed assessment of ertapenem-associated signals. A total of 2,931 reports with ertapenem as the primary suspected drug were collected, covering 27 system organ classes (SOCs). The two SOCs with the strongest signals were nervous system disorders and psychiatric disorders, with overall stronger signals in individuals aged ≥ 65 years. The most frequently reported AEs were confusional state (n = 265) and convulsions (n = 214). Among the strongest signals were oropharyngeal edema (ROR = 191.05, 95% CI: 60.76-601.35) and granulomatous dermatitis (ROR = 150.49, 95% CI: 55.9-405.15). Eleven AEs not listed on the FDA label were identified. The top 20 AEs were predominantly associated with nervous system and psychiatric disorders, with a median time to onset ranging from 3.5 to 8.5 days. This study highlights the neuropsychiatric risks of ertapenem, providing strong evidence for its safety assessment and emphasizing the need for monitoring and individualized management in high-risk patients. Ertapenem, FAERS, Adverse events, Drug safety, Disproportionality analysis.

Carboxymethyl Chitosan Capped Bimetallic Nanoparticles Entrapped in Theranostic Nanofibers: Antimicrobial Peptide Coating, In Vitro, In Vivo Characterization for MDR Microbial Infection and Photoacoustic/Optical Imaging

Wound dressings, integrated with nanotechnology, have garnered considerable attention recently due to their ability to synergistically combine antimicrobial efficacy with wound healing properties, while also supporting adherence to standardized wound care protocols. We have developed smart theranostic wound dressings composed of carboxymethyl chitosan coated gold-silver-LL37 nanoparticles (G-S-CMC-Pep-NPs), of 155.1 ± 11.2 nm in size and a charge over the surface of +34.6 ± 3.7 mV. The optimized G-S-CMC-Pep-NPs were observed to exhibit minimal inhibitory and bactericidal concentration in the range of 0.390-0.781 μg/mL, also illustrated the maximum zone of inhibition (ZOI) of 21.61 ± 1.06 and 18.85 ± 1.22 mm, toward multidrug resistant (MDR) bacteria of P. aeruginosa and S. aureus respectively. TEM analysis of the microbial cells post-12-h treatment revealed irregularly undulating and disrupted cell walls, loss of cell wall integrity, and evidence of DNA condensation. Additionally, hemolysis assays demonstrated that G-S-CMC-Pep-NPs exhibited a nonhemolytic profile when tested on rodent blood, indicating their excellent biocompatibility. Furthermore, G-S-CMC-Pep-NPs were uniformly integrated into chitosan poly(vinyl alcohol) nanofibers (G-S-CMC-Pep-NPs-NFs) having a size ranging from 100 to 350 nm, resulting in an antimicrobial wound dressing, when applied to microbial-infected wounds in mice, achieved a 92.4% wound closure rate within 12 days of treatment. Additionally, this study is further substantiated through the analysis of wound marker protein expression levels, along with in vivo optical and ultrasound/photoacoustic imaging. The ultrasound/photoacoustic imaging offered an in-depth evaluation of the complex wound healing mechanism, enabling real-time visualization, high-resolution spatial imaging, and precise assessment of blood flow dynamics.

Antifouling Activity of Bottlebrush Network Hydrogels

Mitigating the attachment of microorganisms to polymer biomaterials is critical for preventing hospital-acquired infections. Two chemical strategies to mitigate fouling include fabricating fouling-resistant surfaces, which typically present hydrophilic polymers, such as polyethylene glycol (PEG), or creating fouling-release surfaces, which are generally hydrophobic featuring polydimethylsiloxane (PDMS). Despite the demonstrated promise of employing PEG or PDMS, amphiphilic PEG/PDMS copolymer materials remain understudied. Here, for the first time, we investigated if phase-separated amphiphilic copolymers confounded microbial adhesion. We used bottlebrush amphiphilic PEG/PDMS co-networks and homopolymer networks to study bacterial adhesion across a library of gels (ϕPEG = 0.00, 0.21, 0.40, 0.55, 0.80, and 1.00). Hydrated atomic force microscopy measurements revealed that most of the gels had low surface roughness, less than 5 nm, and an elastic modulus of ∼80 kPa. Interestingly, the surface roughness and elastic modulus of the ϕPEG = 0.40 gel were twice as high as those of the other gels due to the presence of crystalline domains, as confirmed using polarized optical microscopy on the hydrated gel. The interactions of these six well-characterized gels with bacteria were determined using Escherichia coli K12 MG1655 and Staphylococcus aureus SH1000. The attachment of both microbes decreased by at least 60% on all polymer gels versus the glass controls. S. aureus adhesion peaked on the ϕPEG = 0.40, likely due to its increased elastic modulus, consistent with previous literature demonstrating that modulus impacts microbial adhesion. These findings suggest that hydrophilic, hydrophobic, and amphiphilic biomaterials effectively resist the early attachment of Gram-negative and Gram-positive microorganisms, providing guidance for the design of next-generation antifouling surfaces.

Quinoline ATP Synthase Inhibitors with Activity Against Multidrug Resistant Acinetobacter baumannii and Pseudomonas aeruginosa

The Gram-negative, pathogenic bacteria Acinetobacter baumannii (AB) and Pseudomonas aeruginosa (PA) have been identified as a particular threat due to rising multidrug resistance, and antibiotics with novel mechanisms of action are needed. Bacterial bioenergetics is a promising but underdeveloped drug target since the complexes of oxidative phosphorylation are critical to cell survival in these organisms. Building from our previous work using quinoline derivatives to inhibit the ATP synthase of PA, we report a new set of 14 quinoline derivatives that demonstrates potent inhibition of the AB ATP synthase, with the best inhibitor having an IC50 of 230 ng/mL in vitro, expands the quinoline structure-activity relationship against the PA enzyme, and establishes molecular strategies for achieving selectivity between PA and AB. Furthermore, several compounds demonstrated potent antibacterial activity against multidrug resistant strains of AB and PA indicating ATP synthase as a promising new area for broad spectrum antibiotic development in AB.

Distribution and drug resistance analysis of pathogens in early-stage digestive tract perforation complicated with peritonitis

To investigate the distribution and drug resistance of pathogens associated with early-stage digestive tract perforation with peritonitis. A retrospective analysis was conducted on patients with digestive tract perforation and peritonitis at Huadu District People's Hospital of Guangzhou from Jan. 2020 to Aug. 2024. The selected patients were divided into two groups: the upper digestive tract (UDT) group and the lower digestive tract (LDT) group. General clinical characteristics and intraoperative secretions culture results were compared and analyzed. The study included 831 patients; 41.28% were in UDT group followed 58.72% in LDT group. 694 strains that isolated comprised 503 Gram-negative bacteria (GNB), 93 g-positive bacteria (GPB) and 98 fungi. Compared to LDT group, the UDT group had a higher positive rate of GPB and fungi but a lower positive rate of GNB. The most common pathogens among GNB were E.coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae; among GPB were Streptococcus anginosus, Enterococcus aviae, and Streptococcus constellations; among fungi were Candida albicans, Candida glabrata, and Candida Cruxalis. We further analyzed drug susceptibility results to related antibacterial drugs. The findings from this study have significant implications for guiding initial empirical antimicrobial therapy for patients with digestive tract perforation and peritonitis.

Gender differences in global antimicrobial resistance

Antimicrobial resistance is one of the leading causes of mortality globally. However, little is known about the distribution of antibiotic resistance genes (ARGs) in human gut metagenomes, collectively referred to as the resistome, across socio-demographic gradients. In particular, limited evidence exists on gender-based differences. We investigated how the resistomes differ between women and men in a global dataset of 14,641 publicly available human gut metagenomes encompassing countries with widely variable economic statuses. We observed a 9% higher total ARG load in women than in men in high-income countries. However, in low- and middle-income countries, the difference between genders was reversed in univariate models, but not significant after adjusting for covariates. Interestingly, the differences in ARG load between genders emerged in adulthood, suggesting resistomes differentiate between genders after childhood. Collectively, our data-driven analyses shed light on global, gendered antibiotic resistance patterns, which may help guide further research and targeted interventions.

Trihydroxybenzaldoximes are Redox Cycling Inhibitors of ThDP-Dependent DXP Synthase

Pathogenic bacteria must swiftly adapt to dynamic infection environments in order to survive and colonize in the host. 1-Deoxy-d-xylulose-5-phosphate synthase (DXPS) is thought to play a critical role in bacterial adaptation during infection and is a promising drug target. DXPS utilizes a thiamine diphosphate (ThDP) cofactor to catalyze the decarboxylative condensation of pyruvate and d-glyceraldehyde-3-phosphate (d-GAP) to form DXP, a precursor to isoprenoids and B vitamins. DXPS follows a ligand-gated mechanism in which pyruvate reacts with ThDP to form a long-lived lactyl-ThDP (LThDP) adduct which is coordinated by an active-site network of residues. d-GAP binding ostensibly disrupts this network to activate LThDP for decarboxylation. Our lab previously reported trihydroxybenzaldoxime inhibitors which are competitive with respect to d-GAP, and uncompetitive with respect to pyruvate, suggesting they bind after E-LThDP complex formation. Here, we conducted mechanistic studies to determine if these compounds inhibit DXPS by preventing LThDP activation or if they act as inducers of LThDP activation. We discovered that the catechol moiety of the trihydroxybenzaldoxime scaffold undergoes oxidation under alkaline aerobic conditions, and inhibitory potency is reduced under oxygen restriction. Leveraging long-range 1H-15N HSQC NMR and electrochemical measurements, we demonstrated that the oxidized form of the trihydroxybenzaldoxime induces LThDP decarboxylation and accepts electrons from the resulting carbanion, resulting in reduction to the catechol and formation of acetyl-ThDP which hydrolyzes to form acetate. Under aerobic conditions the catechol is reoxidized. Thus, these compounds act as redox cycling, substrate-wasting inhibitors of DXP formation. These findings uncover a novel activity and mechanism of DXPS inhibition which may have implications for DXPS-mediated redox activity in bacteria. Further exploration of redox active DXPS probes may provide new insights for inhibition strategies and selective probe development.

Antimicrobial Resistant Staphylococcus spp., Escherichia coli, and Salmonella spp. in Food Handlers: A Global Review of Persistence, Transmission, and Mitigation Challenges

Antimicrobial resistance in foodborne pathogens represents a critical global health challenge, with food handlers serving as key contributors in their transmission. This comprehensive review synthesizes evidence on the prevalence, transmission dynamics, and antimicrobial resistance patterns of three major pathogens, Staphylococcus spp., Escherichia coli, and Salmonella spp., among food handlers worldwide. Analysis of studies across diverse geographical regions reveals considerable variation in colonization rates, with Staphylococcus spp. prevalence ranging from 19.5% to 95.0%, Escherichia coli from 2.8% to 89.3%, and Salmonella spp. from 0.07% to 9.1%. Resistance profiles demonstrate alarming trends, including widespread β-lactam resistance and emerging resistance to last-resort antibiotics like carbapenems. Particularly concerning is the high occurrence of multidrug resistant (MDR) strains and extended spectrum β-lactamase (ESBL) producers in low- and middle-income countries. This review identified inadequate handwashing, poor hygiene infrastructure, and asymptomatic carriage as critical factors facilitating the transmission of antimicrobial resistant strains. These findings underscore the urgent need for enhanced surveillance systems, targeted decolonization strategies, improved hygiene protocols, and food handler education to mitigate the spread of resistant pathogens through the food chain.

Pioneering bactericidal efficacy with nitrogen doping and zinc oxide nanoparticle decoration on carbon nanosheets

The escalating prevalence of drug-resistant pathogens poses a significant threat to global health, contributing to elevated mortality rates and inflated healthcare expenses. To combat antibacterial resistance, carbon-based nanocomposites incorporating metal oxides have emerged as a promising solution in the development of advanced antibacterial agents. In this quest, we propose a nascent strategy to synthesize zinc oxide-decorated carbon nanosheets (ZnO@CNSn) via a co-precipitation method. The crystalline ZnO nanoparticles (ZnO-NPs) are homogeneously dispersed throughout a framework of melamine-enriched carbon nanosheets (CNSn). The presence of pyrrolic-N and pyridinic-N functionalities in ZnO@CNSn enhances the charge transfer kinetics and creates nucleation sites for uniform dispersion of ZnO-NPs, mitigating particle aggregation. Remarkably, XPS analysis reveals a distinct shift in peak intensity, characterized by a reduction in pyrrolic-N and a corresponding increase in pyridinic-N. This conversion of pyrrolic-N to pyridinic-N due to incorporation of ZnO-NPs onto CNSn plays a crucial role in improving its bactericidal effect. The antibacterial assays against Gram negative Escherichia coli, Gram positive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) confirm the bactericidal activity of ZnO@CNSn. Additionally, the SEM micrographs show altered bacterial morphology on interaction with the nanocomposites, further validating the effective bactericidal properties. Moreover, ZnO@CNSn exhibits enhanced cytocompatibility compared to CNSn. These findings underscore the promising potential of the ZnO-decorated CNSn architecture as a robust platform for advanced antibacterial applications.

Epidemiological and genomic insights of mcr-1-positive colistin-resistant Klebsiella pneumoniae species complex strains from wastewater treatment plants in Shanghai

The emergence of mcr-1-positive Klebsiella pneumoniae species complex (MP-KpSC) poses a significant threat to public health due to its resistance to last-resort antibiotics like colistin. This study aimed to investigate the prevalence, genomic characteristics, and transmission features of MP-KpSC in wastewater treatment plants (WWTPs) in Shanghai, China. A total of 13 (0.36 %) MP-KpSC isolates were identified, including 12 K. pneumoniae and 1 K. quasipneumoniae subsp. similipneumoniae (Kqps). Nine multidrug-resistant (MDR) MP-KpSC and 3 extensively drug-resistant (XDR) MP-KpSC strains were identified. Twenty-two resistance determinants were present in over 30 % of the strains, with the most prevalent being mcr-1 (100 %), floR (84.62 %), mphA (69.23 %), and tet(A) (69.23 %). MP-KpSC exhibited 11 sequence types, 4 plasmid types, 6 mcr-1-flanked regions, 4 clonal groups, and diverse serotypes. In 53.85 % of strains, transposons were identified within the mcr-1-flanked regions. One strain contained both mcr-8.2 and mcr-1 gene. Notably, the mcr-1 gene was identified for the first time in Kqps and was located on the conjugative IncP1 plasmid, with ISApl1 elements upstream of it. Worryingly, two carbapenem- and colistin-resistant XDR MP-KpSC stains, and three possible hypervirulence (hv) were found in MDR MP-KpSC strains. Moreover, multiple virulence genes and mcr-1, on the same contig with IS679 insert element. The evolutionary trajectories of these strains among WWTPs-human-animals were unveiled in Shanghai. The study reveals that WWTPs serve as critical environmental reservoirs for MP-KpSC, highlighting the potential transmission risks posed by XDR and hv strains to both humans and aquatic ecosystems. These findings advocate for the implementation of active surveillance targeting WWTPs to curb the spread of MP-KpSC.

Evaluating the impact of artificial intelligence in antimicrobial stewardship: a comparative meta-analysis with traditional risk scoring systems

OBJECTIVES

The growing challenge of antimicrobial resistance (AMR) has underscored the urgent need for robust antimicrobial stewardship programs (AMS). Artificial intelligence (AI) and machine learning (ML) have emerged as promising tools to support enhanced decision-making in AMS. This systematic review and meta-analysis aims to evaluate the impact of AI in AMS and compare its effectiveness with traditional risk systems.

METHODS

PubMed/MEDLINE, Scopus, EMBASE, and Web of Science were searched to identify studies published up to July 2024. Any studies that evaluated the use of AI/ML in AMS compared with conventional decision-making approaches were eligible. Outcomes of interested were predictive performance metrics and diagnostic accuracy. The meta-estimate was performed pooling standardized mean difference, and effect size (ES) measured as Cohen's d with a 95% confidence interval (CI). The risk of bias was assessed using the QUADAS-AI tool.

RESULTS

Out of 3,458 studies, 27 were included, demonstrating that ML models outperform traditional methods in terms of sensitivity [1.93 (0.48-3.39) p = 0.009], and negative predictive value [1.66 (0.86-2.46), p < 0.001] but not in terms of area under the curve, accuracy, specificity, positive predictive value, when random effect models were applied.

CONCLUSIONS

Our results revealed that ML tools offer promising enhancements to traditional AMS strategies. However, high heterogeneity, inconsistent results between fixed and random effect models, and limited use of external validation in retrieved studies raise concerns about the generalizability of the findings. Furthermore, the lack of representation from outpatient and pediatric settings highlights a critical equity gap in the application of these technologies.

Plasmid-bacteria associations in the clinical context

Antimicrobial resistance (AMR) is one of the most pressing global health problems, with plasmids playing a central role in its evolution and dissemination. Over the past decades, many studies have investigated the ecoevolutionary dynamics between plasmids and their bacterial hosts. However, what drives the epidemiological success of certain plasmid-bacterium associations remains unclear. In this opinion article, we review which factors influence these associations and underline that studying plasmid-host interactions of clinical relevance is critical for understanding the evolution and spread of AMR. We also highlight the increasing importance of integrating experimental research with bioinformatics and machine learning tools to study plasmid-bacteria dynamics. This combined approach will assist researchers to dissect the molecular mechanisms underlying successful plasmid-host associations and to design strategies to prevent and predict future high-risk associations.

Throwing a spotlight on genomic dark matter: the power and potential of transposon-insertion sequencing

Linking genotype to phenotype is a central goal in biology. In the microbiological field, transposon mutagenesis is a technique that has been widely used since the 1970's to facilitate this connection. The development of modern 'omics approaches and next-generation sequencing, have allowed high-throughput association between genes and their putative function. In 2009, four different variations of modern transposon-insertion sequencing (TIS) approaches were published, being referred to as transposon-directed insertion-site sequencing (TraDIS), transposon sequencing (Tn-seq), insertion sequencing (INSeq) and high-throughput insertion tracking by deep sequencing (HITS). These approaches exploit a similar concept to allow estimation of the essentiality or contribution to fitness of each gene in any bacterial genome. The main rationale is to perform a comparative analysis of the abundance of specific transposon mutants under one or more selective conditions. The approaches themselves only vary in the transposon used for mutagenesis, and in the methodology used for sequencing library preparation. In this review, we discuss how TIS approaches have been used to facilitate a major shift in our fundamental understanding of bacterial biology in a range of areas. We focus on several aspects including pathogenesis, biofilm development, polymicrobial interactions in various ecosystems, and antimicrobial resistance. These studies have provided new insight into bacterial physiology and revealed predicted functions for hundreds of genes previously representing genomic 'dark matter'. We also discuss how TIS approaches have been used to understand complex bacterial systems and interactions and how future developments of TIS could continue to accelerate and enrich our understanding of bacterial biology.

Development of a novel risk score for diagnosing urinary tract infections: Integrating Sysmex UF-5000i urine fluorescence flow cytometry with urinalysis

BACKGROUND

Urinary tract infections (UTIs) are common globally, and are developing increased antibiotic resistance. Despite being the diagnostic "gold standard," urine culture is limited by slow results and a high rate of false negative findings, leading to treatment delays, higher costs, and overuse of empirical antibiotics. Our study aims to develop a rapid and reliable model to predict clinical outcomes.

METHODS

From January 1st to October 31st, 2023, we enrolled patients with symptoms suggesting UTI from the Outpatient Department of our hospital. Inclusion criteria were patients aged ≥18, initially diagnosed with UTI, available urinalysis, flow cytometry, and urinary culture. Exclusion criteria included failed sample collection and cultures, and pregnant women. A case-control study was conducted, with UTI cases defined as ≥ 10^5 CFU/ µ L and controls as < 10^5 CFU/ µ L, matched for age and sex in a 1:1 ratio. For validation, retrospective cases from July to December 2022 were selected with matching controls. Using urine culture as the gold standard, the predictive model was developed with backward stepwise logistic regression. Model discrimination was assessed using area under the curve (AUC).

RESULTS

In our discovery cohort, we included 1,335 UTI cases and 1,282 non-UTI controls, with mean ages of 52.9 ± 17.1 years and 51.9 ± 16.4 years, and females of 76.9% and 77.7%. Using 100 cells/uL as a threshold, bacterial counts demonstrated a sensitivity of 91.0% and specificity of 45.7%. Our novel UTIRisk score, developed from urinalysis and flow cytometry parameters, showed strong discrimination for UTI, with a AUC of 0.82 (95% CI: 0.81-0.84). In the validation cohort, the AUC was 0.77 (95% CI: 0.74-0.80). The UTIRisk score exhibited excellent specificity (96.5%) and high positive predictive value (92.6%). The score performed strongly across subgroups, particularly in males and patients aged ≥65.

CONCLUSIONS

Our UTIRisk score can improve diagnosis, reduce unnecessary urine cultures, optimize antibiotic use, and help control antibiotic resistance in LMICs. Multicenter, and intervention-based studies are warranted before clinical implementation.

A critical review on In Vivo and Ex Vivo models for the investigation of Helicobacter pylori infection

Helicobacter pylori is a stomach-dwelling bacterium with a crude global prevalence of nearly 45% in adults and 35% in children and adolescents. Chronic H. pylori infection and the resulting inflammation are major causes of gastritis, peptic ulcer disease and gastric cancer. Since its discovery in 1982, various animal models have been proposed to recreate the specific pathophysiological interactions between H. pylori and the human host. These infection models have been instrumental in dissecting the key drivers of H. pylori colonization, persistence and mediators of host immune responses. However, a comprehensive understanding of the molecular triggers for malignant transformation of the gastric mucosa is still lacking. Vaccine development in this area has stalled, as promising candidates identified through animal studies have failed in advanced human clinical trials. Currently, H. pylori eradication is heavily reliant on different antimicrobial agents. As with other bacterial pathogens, the growing antimicrobial resistance in H. pylori remains a major challenge, making eradication therapy increasingly complex and prolonged, over time. Recent drug approvals have mostly been for newer combinations of conventional antibiotics and proton pump inhibitors. Thus, the development of novel treatments and innovative models are crucial for advancing the drug development pipeline. This review encompasses the development and recent advances in animal and non-animal models of H. pylori gastric infection and its applications in investigating novel therapeutics and vaccine candidates.

Comprehensive wound healing using ETN@Fe7S8 complex by positively regulating multiple programmed phases

Wound healing requires coordinated progression through multiple programmed phases including hemostasis, infection control, inflammatory resolution, proliferation, and tissue remodeling. Many nanomaterials have shown great potential to promote wound healing, however, most of them only address partial aspects of these processes, making a recovery hard with adequate effects. In this study, we prepared a complex of nano-iron sulfide integrated with erythrocyte-templated nanozyme (ETN) (ETN@Fe7S8) for comprehensive treatment of wounds. Firstly, ETN served as a mediator to confine iron sulfide to form Fe7S8 nanocomposite in a solvothermal reaction. Secondly, the ETN@Fe7S8 demonstrated bactericidal effects against methicillin-resistant Staphylococcus aureus (MRSA) by releasing ferrous iron and polysulfide to induce ferroptosis-like cell death. Thirdly, ferrous iron along with polysulfide exerted anti-inflammatory effects by inhibiting the activation of the NF-κB signaling pathway, while the polysulfide also contributed to angiogenesis by promoting the activation of vascular endothelial growth factor A (VEGFA), initiated phosphorylation-mediated activation of the PI3K/AKT signaling pathway, a master regulatory cascade governing endothelial cell survival, migration, and angiogenesis. When employed for wound, ETN@Fe7S8 showed the ability to prevent infection, reduce inflammation, promote angiogenesis, enhance cell proliferation, and remodel keratinocytes. Along with the hemostatic effect, ETN@Fe7S8 thus performed comprehensive effects for wound healing in the whole recovery stages. Therefore, our findings provide a multifunctional candidate of ETN and nano-iron sulfide complex which is capable of regulating and promoting wound healing.

Phage Therapy for Urinary Tract Infections: Progress and Challenges Ahead

INTRODUCTION AND HYPOTHESIS

Urinary tract infection (UTI) treatment is a growing public health concern owing to increasing antimicrobial resistance. Phage therapy, an alternative or adjunctive treatment to antibiotics, has the potential to address this challenge. However, clinical use of phage therapy is hindered by knowledge gaps and inconsistent reporting. The objective was to review the current state of phage therapy for UTIs and highlight research priorities that can optimize phage clinical efficacy.

METHODS

Current literature on UTI phage therapy was examined, focusing on the lack of standardized phage susceptibility testing, phage characterization, and microbiological assessments during and after treatment.

RESULTS

Critical areas requiring further investigation include appropriate phage dosing, optimal routes of administration, and the dynamics of phage-host and phage-patient interactions. The influence of the urinary microbiome, including endogenous phages, on treatment outcomes also needs to be better understood. Suggested data collection and reporting standards should be developed and implemented to improve clinical impact of studies examining phage therapy for UTI. Randomized clinical trials are needed to establish efficacy and determine the best practices for clinical use.

CONCLUSION

Phage therapy is a promising alternative to antibiotics for managing UTIs, especially in the face of rising antimicrobial resistance. To fully realize its potential, however, future research must focus on standardized protocols, dosing strategies, and the role of the urinary microbiome, with an emphasis on rigorously conducted clinical trials. These steps are essential for integrating phage therapy into mainstream UTI treatment regimens.

Chemical Innovations of Antimicrobial Polymers for Combating Antimicrobial Resistance

The global rise of antimicrobial resistance (AMR) has rendered many traditional antibiotics ineffective, leading to an urgent need for alternative therapeutic strategies. Antimicrobial polymers, with their ability to rapidly kill bacteria by disrupting or crossing membranes and/or targeting multiple microbial functions without inducing resistance, offer a promising solution. This perspective explores recent innovations in the design and synthesis of antimicrobial polymers, focusing on their chemical motifs, structural derivatives, and their applications in combating systemic and topical infections. We also highlight key challenges in translating these materials from laboratory research to clinical practice, including issues related to the high dose required, bioavailability and stability in systemic infection treatment, and ability to disperse and kill biofilms in localized infection management. By addressing these challenges, antimicrobial polymers could play a crucial role in the development of next-generation therapeutics to combat multidrug-resistant pathogens. This perspective attempts to summarize significant insights for the design and development of advanced antimicrobial polymers to overcome AMR, offering potential pathways to improve clinical outcomes in treating systemic and local infections.

Revolutionizing agroindustry: Towards the industrial application of antimicrobial peptides against pathogens and pests

Antibiotics are essential chemicals for medicine and agritech. However, all antibiotics are small molecules that pathogens evolve antimicrobial resistance (AMR). Alternatively, antimicrobial peptides (AMPs) offer potential to overcome or evade AMR. AMPs provide broad-spectrum activity, favourable biosafety profiles, and a rapid and efficient mechanism of action with low resistance incidence. These properties have driven innovative applications, positioning AMPs as promising contributors to advancements in various industrial sectors. This review evaluates the multifaceted nature of AMPs and their biotechnological applications in underexplored sectors. In the food industry, the application of AMPs helps to suppress the growth of microorganisms, thereby decreasing foodborne illnesses, minimizing food waste, and prolonging the shelf life of products. In animal husbandry and aquaculture, incorporating AMPs into the diet reduces the load of pathogenic microorganisms and enhances growth performance and survival rates. In agriculture, AMPs provide an alternative to decrease the use of chemical pesticides and antibiotics. We also review current methods for obtaining AMPs, including chemical synthesis, recombinant DNA technology, cell-free protein synthesis, and molecular farming, are also reviewed. Finally, we look to the peptide market to assess its status, progress, and transition from the discovery stage to benefits for society and high-quality products. Overall, our review exemplifies the other side of the coin of AMPs and how these molecules provide similar benefits to conventional antibiotics and pesticides in the agritech sector.

Genomic perspectives on NDM Salmonella Typhi, and a case report from India

BACKGROUND

Carbapenem resistance in Enterobacterales is a growing public health concern, primarily driven by carbapenemase enzymes such as OXA-48, VIM, NDM, and IMP. Among these, New Delhi Metallo-β-lactamase (NDM) has disseminated widely across various Enterobacterales species, including Salmonella Typhi, though reports remain rare.

CASE PRESENTATION

We report an 11-year-old boy from Bangalore with a 10-day history of high-grade fever, chills, rigors, and cough. Laboratory investigations revealed elevated CRP, normal CBC, and microcytic hypochromic anemia. A respiratory panel detected Human Rhinovirus/ Enterovirus. Blood cultures grew non-lactose fermenting gram-negative bacilli, identified as Salmonella spp. via Vitek ID/AST. The isolate exhibited resistance to ampicillin, ciprofloxacin, ceftriaxone, tetracycline, and meropenem but remained susceptible to azithromycin, chloramphenicol, and Co-trimoxazole. Serotyping confirmed the serotype as Salmonella Typhi. Whole-genome sequencing (Illumina) revealed blaNDM-5 and aac(6')-Ia, InCX3 plasmid, and the fluoroquinolone resistance-associated gyrAS83Y mutation. Phylogenetic analysis placed the isolate (IOB-SWH-01) within a cluster of recently sequenced S. Typhi strains from India belonging to the H58 haplotype.

DISCUSSION AND CONCLUSION

To date, NDM-producing S. Typhi has been reported only once, from Pakistan. This is the first documented case in India. The presence of blaNDM-5 in S. Typhi poses a serious clinical and public health threat, given its multidrug-resistant nature and potential for interspecies transmission. Continued genomic surveillance is crucial to monitor its spread and guide treatment strategies.

Drug-resistance patterns and associated mutations of Mycobacterium tuberculosis strains isolated from chronic kidney disease and diabetes mellitus patients in Ethiopia

OBJECTIVE

To assess the drug-resistance (DR) patterns, mutations, and associated factors among tuberculosis (TB) cases identified from diabetic mellitus (DM) and chronic kidney disease (CKD) patients.

METHODS

The drug-resistance patterns of 77 Mycobacterial isolates were assessed using phenotypic drug-susceptibility testing (DST), the Xpert MTB/RIF assay, the Xpert MTB/XDR assay, and line probe assays. Data were analyzed using SPSS version 27. Descriptive statistics, a chi-squared test, and logistic regression were conducted. The 95%CI was determined and a P-value <0.05 was considered as a statistically significant difference.

RESULTS

Resistance pattern was determined for 76 Mycobacterial isolates and one isolate had an invalid result. Any drug resistance and multi-drug resistance were detected among 25.0% (19), and 7.9% (6) isolates, respectively. Resistance to streptomycin (STR), isoniazid (INH), rifampicin (RIF), ethambutol, and pyrazinamide (PZA) was 11.8% (9), 13.2% (10), 10.5% (8), 6.6% (5), and 11.8%(9), respectively. Mono-drug resistance was detected for STR 3.9% (3), INH 2.6% (2), RIF 2.6% (2), and PZA 4.5% (4). One isolate was resistant to fluoroquinolones (FLQ). Phenotypic and genotypic methods had concordance results in determining RIF and FLQ resistance. The common RIF and INH-resistant conferring mutations were observed at the S531L and S315T regions, respectively. Previous TB treatment, and TB contact history were associated with DR-TB.

CONCLUSION

A quarter of TB cases identified had DR-TB with a higher risk among patients with previous TB treatment history and had contact with TB patients necessitating programmatic interventions including applying infection prevention, contact tracing, and access to DST using rapid molecular methods.

The dark matter of bacterial genomic surveillance-antimicrobial resistance plasmid transmissions in the hospital setting

Dissemination of antimicrobial resistance (AMR) is a growing global public health burden. The aim of this study was to characterize AMR plasmid transmissions within a tertiary care hospital and identify relevant AMR plasmid transmission pathways. During an 18-month observation period, 540 clinical gram-negative multidrug-resistant bacterial (MDRB) isolates were collected during routine hospital surveillance and subjected to Pacific Biosciences long-read whole genome sequencing. Potential clonal transmissions were determined based on core genome multilocus sequence typing (cgMLST), and plasmid transmissions were detected using a novel real-time applicable tool for plasmid transmission detection. Potential transmissions were validated using epidemiological data. Among the 471 eligible MDRB isolates, we detected 1,539 plasmids; 84.41% of these were circularized. We identified 38 potential clonal transmissions in 24 clusters based on cgMLST and 121 potential plasmid transmissions in 24 clusters containing genetically related AMR plasmids. Among the latter clusters, 10 contained different multilocus sequence types (involving 2-38 isolates, median: 3 isolates), and nine contained multiple species (2-18 isolates, median: 4). Epidemiological data confirmed 19 clonal transmissions (in seven clusters) and an additional 12 plasmid transmissions (within eight plasmid clusters). Among these, we identified seven cases of intra-host and five patient-to-patient plasmid transmissions. We demonstrate that intra-host and patient-to-patient transmissions of AMR plasmids can be identified by combining long-read sequencing with real-time applicable tools during routine molecular surveillance. In addition, our study highlights that more than a decade of bacterial genomic surveillance missed at least one-third of all AMR transmission events due to plasmids.

IMPORTANCE

Antimicrobial resistance (AMR) poses a significant threat to human health. Most AMR determinants are encoded extra-chromosomally on plasmids. Although current infection control strategies primarily focus on clonal transmission of multidrug-resistant bacteria, until today, AMR plasmid transmission routes are neither understood nor analyzed in the hospital setting. In our study, we simultaneously determined both clonal, that is, based on chromosomes, and AMR plasmid transmissions during routine molecular surveillance by combining long-read sequencing with a novel real-time applicable software tool and validated all potential transmission events with epidemiological data. Our analysis determined not only the yet unknown plasmid transmissions within healthcare facilities or within the community but also resulted, in addition to the clonal transmissions, in at least a third more transmissions due to AMR plasmids.

Identification of Bacterial Oligopeptidase B Inhibitors from Microbial Natural Products: Molecular Insights, Docking Studies, MD Simulations, and ADMET Predictions

Background/Objectives: The increasing threat of antibiotic resistance and the declining efficiency of traditional drug discovery pipelines highlight the urgent need for novel drug targets and effective enzyme inhibitors against infectious diseases. Oligopeptidase B (OPB), a serine protease with trypsin-like specificity that processes low-molecular-weight peptides and oligopeptides, is present in bacteria and certain parasites but absent in mammals. This unique distribution makes OPB an attractive and selective target for antimicrobial drug development. Methods: Three-dimensional models of OPB from Serratia marcescens and Stenotrophomonas maltophilia, previously identified by our research group, were constructed via homology modeling using the best available OPB template from the RCSB Protein Data Bank. The S. marcescens OPB model was subjected to high-throughput virtual screening (HTVS) against the Natural Products Atlas (npatlas) database. Top-ranking compounds were further evaluated using Glide standard precision (SP) and extra precision (XP) docking protocols. Binding affinities were refined using molecular mechanics with generalized born and surface area (MM-GBSA) calculations. Molecular dynamics (MD) simulations assessed binding stability, while absorption distribution metabolism excretion and toxicity (ADMET) profiling evaluated drug-likeness and pharmacokinetic properties. Results: Ten natural product compounds demonstrated stronger binding affinities than antipain, a well-known oligopeptide-based protease inhibitor, as indicated by their more favorable MM-GBSA scores of -60.90 kcal/mol (S. marcescens) and -27.07 kcal/mol (S. maltophilia). Among these, dichrysobactin and validamycin E consistently exhibited favorable binding profiles across both OPB models. MD simulations confirmed the stability of their interactions with OPB active sites, maintaining favorable binding conformations throughout the simulation period. ADMET analysis suggested that while both compounds show promise, lead optimization is required to enhance their drug-like characteristics. Conclusions: This study identifies dichrysobactin and validamycin E as promising OPB inhibitors with potential antimicrobial activity. These findings support their further development as selective and potent agents against bacterial pathogens, including resistant strains, and underscore the need for experimental validation to confirm their efficacy and safety.

Biofilm-disrupting DNA nanomedicines for targeted elimination of resistant wound microbiota

Biofilms are complex bacterial communities that significantly hinder the treatment of chronic and recurrent infections by enhancing bacterial virulence and conferring resistance to antimicrobial therapies. To address this challenge, an intelligent DNA nanomedicine has been engineered to dismantle biofilms and target resistant bacteria, offering an innovative solution for chronic wound infections. These nanomedicines initiate biofilm degradation through in situ generation of potent oxidative radicals, enabling deep biofilm penetration and precise bacterial targeting. Utilizing aptamers for specific bacterial identification, the nanomedicines concentrate therapeutic agents directly at infection sites. The combined effect of severe oxidative stress and sustained silver ion release ensures a continuous, focused assault on pathogens, effectively eradicating resistant bacteria. This strategy demonstrated broad-spectrum efficacy against both Gram-positive and Gram-negative bacteria, significantly enhancing wound healing in a diabetic infection model. By integrating intelligent bacterial eradication with modulation of the wound microenvironment, this approach presents a promising solution for overcoming biofilm-associated resistance and advancing chronic wound infection treatment.

Exploring Policies, Strategies, and Legislations Related to the One Health Approach to Zoonoses, Antimicrobial Stewardship, and Climate Change in Jordan: A Multimethod Study with SWOT Analysis

Background: Mapping policies, strategies, and legislations related to disease prevention in Jordan is pivotal for strengthening the country's public health infrastructure. The aims of our study were to identify, review, and map the existing national policies, strategies, and legislations related to the One Health approach to zoonoses, antimicrobial stewardship (AMS), and climate change in Jordan. Additionally, we identified the key strengths and major gaps and uncovered opportunities for enhancement. The current paper reports a part of a nationwide project which was jointly executed in 2023 by the Jordan Center for Disease Control and the Health Care Accreditation Council. Methods: A multimethod approach was employed, including a comprehensive desk review of any existing policies, strategies, and legislations, along with key informant interviews involving key stakeholders. The combination of the desk review and key informant interviews allowed for a more nuanced understanding of the gaps, strengths, and challenges in Jordan's approach to One Health, AMS, and climate change adaptation. By triangulating the findings from both methods, the study was able to cross-validate its results and ensure greater reliability and accuracy in its conclusions. Results: Our analyses revealed that Jordan has made notable progress in integrating the One Health approach within its regulatory framework, particularly in managing zoonotic diseases, AMS, and climate change. Nevertheless, there is a need for more explicit and effective intersectoral coordination. While the country's AMS initiatives are supported by a national action plan, they are limited by inadequate public awareness, veterinary regulations, and monitoring systems. Moreover, Jordan's climate change strategies, aligned with broader sustainability goals and integrated into national frameworks like the environmental protection law, are constrained by a lack of emergency preparedness and multisectoral collaboration. The SWOT analysis highlighted strengths, including robust legal structures and international collaborations, while identifying gaps in enforcement and the need for updated guidelines. Opportunities exist to enhance the reporting mechanisms, public awareness, and international partnerships. Conclusions: Jordan's integration of the One Health approach to zoonotic diseases, AMS, and climate change adaptation into its disease prevention policies is commendable and aligns with global health priorities. To further enhance these initiatives, Jordan could benefit from updating its public health law and the relevant guidelines and policies, strengthening and structuring public awareness campaigns, and developing detailed climate change adaptation strategies.

Antimicrobial Resistance (AMR) Development Map: A Conceptual Map and a Tool to Support Economic Evaluation of AMR Interventions

INTRODUCTION

Antimicrobial resistance (AMR) is a complex, inter-sectoral and international problem. Economic evaluation (EE) methods offer systematic, evidence-driven approaches to inform policy decisions about which AMR interventions to fund. EE of AMR interventions is complicated owing to diffuse effects, complex mechanics of the problem and high levels of uncertainty. Current AMR EE literature restricts the analytical scope, potentially resulting in omissions of effects that may limit the utility of EE to inform policy decisions. We aimed to systemise the key evolutionary and ecological processes of AMR to elucidate the paths through which AMR interventions impact population health and healthcare costs to support EE design and to support decision makers in understanding the limitations of EE evidence for decision-making.

METHODS

A conceptual map and a corresponding tool were developed on the basis of a literature review in consultation with experts across the relevant disciplines of molecular biology, infectious disease modelling, health economics and ecology.

RESULTS

The AMR development map: (1) distils the key AMR processes and process drivers behind AMR development and maps the available types of AMR interventions to AMR process drivers; (2) proposes a way to conceptualise the spatial scope of analysis through considering the connectivity of the wider ecosystem and (3) outlines the key dimensions that AMR burden and intervention effects could be measured across. An AMR development map tool was developed to support conceptual modelling, with the focus on the choice of scope in the EE of AMR interventions, and an illustrative case study was provided.

DISCUSSION

This work summarises the key underlying biological principles of AMR development to provide mechanistical grounding for considering the scope of effects of AMR interventions and the appropriate system of analysis to support conceptual modelling in EE of AMR interventions. In addition, this map can facilitate the identification of effects that cannot be considered or quantified, thus enabling transparency about these omissions within decision-making.

Trends and characteristics of multidrug-resistant MRSA in Norway 2008-2020

Infections caused by multidrug-resistant (MDR) bacteria are recognized as a critical One Health concern which poses a significant threat to public health, leading to increased morbidity and mortality across both high- and low-income countries. In this study, we investigated the epidemiology and molecular mechanisms of multidrug-resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) strains identified in Norway from 2008 to 2020, in order to gain a better understanding of the evolution and dissemination of multidrug resistance in S. aureus. A total of 452 MDR-MRSA strains isolated from 429 individuals were analyzed from a dataset of 23,412 MRSA strains. Methods included epidemiological characterization, antimicrobial susceptibility testing (AST), and genetic analysis of a selection of strains using nanopore sequencing to identify antimicrobial resistance (AMR) genes and mutations, as well as their location on plasmids, SCCmec and other mobile genetic elements (MGEs). The study revealed an overall increasing trend in MDR-MRSA strains, with healthcare-associated strains being more prevalent among MDR-MRSA compared to the overall MRSA population. Significant heterogeneity in spa-types and clonal complexes exhibiting multidrug resistance was observed, with high resistance rates against multiple antibiotic groups, particularly erythromycin, ciprofloxacin/norfloxacin, tetracycline, gentamicin, and clindamycin in addition to cefoxitin. The predominant MDR-MRSA clones included t1476/CC8, t127/CC1, t189/CC188, and t030, t037/CC239. Among these, MRSA t1476/CC8 showed an upward trend toward the conclusion of the study period, indicating the emergence of a MDR-MRSA clone. A broad range of AMR genes and mutations were detected, linked to a wide variety of MGEs, highlighting the complex mechanisms of resistance development and dissemination within the MRSA population. This study highlights the rising challenge posed by MDR-MRSA strains, and reveals the multifactorial nature of AMR in S. aureus, thus emphasizing the importance of continued surveillance, antibiotic stewardship and infection control measures, as well as global cooperation, in order to combat the spread of these multidrug-resistant pathogens.

Bacteriophages as Vehicles for Antibiotic Resistance Genes in the Onyar River, Spain

This study aimed to investigate the presence and abundance of antibiotic resistance genes (ARGs) in bacterial and phage DNA fractions from sediment samples collected from the Onyar River, both before and after its passage through the urban area of Girona (northeast Spain). Genes conferring resistance to β-lactams, fluoroquinolones, macrolides, sulfonamides, and tetracyclines were quantified using quantitative PCR. Our findings showed that ARGs are present in both bacterial and phage DNA fractions, with a higher abundance in the bacterial fraction. Notably, our analysis revealed an increased abundance of the sulfonamide resistance gene sulI in the phage DNA fraction when comparing samples collected before and after the river's passage through the city. Although similar trends were observed for other ARGs (e.g., qnrS and sulII), these differences were not statistically significant (p > 0.05). These findings emphasize the importance of phages as potential reservoirs or vehicles for ARGs in environmental settings. Further research is needed to elucidate the factors that influence gene transfer dynamics and the persistence of ARGs within phages.

Penfluridol synergizes with colistin to reverse colistin resistance in Gram-negative bacilli

The growing prevalence of antibiotic resistance in multidrug-resistant Gram-negative bacteria (MDR-GNB), exacerbated by the misuse of antibiotics, presents a critical global health challenge. Colistin, a last-resort antibiotic for severe MDR-GNB infections, has faced diminishing efficacy due to the emergence of colistin-resistant (COL-R) strains. This study evaluates the potential of penfluridol (PF), an antipsychotic drug with notable antibacterial and antibiofilm properties, to restore colistin activity against COL-R GNB in vitro. PF alone exhibited limited antibacterial activity against COL-R GNB; however, its combination with colistin demonstrated strong synergistic effects, significantly reducing colistin's minimum inhibitory concentrations (MICs) by 4-128 times. Time-kill assays confirmed the combination's superior bactericidal activity compared to either agent alone. Membrane permeability assays revealed that PF enhanced colistin's ability to disrupt bacterial membranes, likely by facilitating colistin binding to lipopolysaccharide. Furthermore, PF significantly inhibited the development of colistin resistance over a 30-day resistance development assay. In addition to its antibacterial effects, PF exhibited notable antibiofilm activity. The combination of PF and colistin effectively inhibited biofilm formation and eradicated mature biofilms in most of the tested COL-R GNB strains. These findings mark the first report of PF's synergistic interaction with colistin against GNB biofilms, offering a promising strategy to combat biofilm-associated infections. Overall, the colistin/PF combination holds potential as an effective therapeutic strategy to enhance colistin efficacy, delay resistance development, and manage biofilm-associated infections in MDR-GNB.

Toward Dual-Target Glycomimetics against Two Bacterial Lectins to Fight Pseudomonas aeruginosa-Burkholderia cenocepacia Infections: A Biophysical Study

Chronic lung infections caused by Pseudomonas aeruginosa and Burkholderia cenocepacia pose a severe threat to immunocompromised patients, particularly those with cystic fibrosis. These pathogens often infect the respiratory tract, and available treatments are limited due to antibiotic resistance. Targeting bacterial lectins involved in biofilm formation and host-pathogen interactions represents a promising therapeutic strategy. In this study, we evaluate the potential of synthetic fucosylamides as inhibitors of the two lectins LecB (P. aeruginosa) and BC2L-C-Nt (B. cenocepacia). Using a suite of biophysical assays, we assessed their binding affinities, identifying three β-fucosylamides as promising dual-target ligands, while crystallography studies revealed the atomic basis of these ligands to interact with both bacterial lectins. The emerged classes of compounds represent a solid starting point for the necessary hit-to-lead optimization for future dual inhibitors aiming at the treatment of coinfections with these two bacterial pathogens.

Attitudes and practices for antibiotic prescription and antimicrobial resistance among general physicians -Findings from a multi-country survey

This study aimed to assess the attitudes, and practices (AP) of general physicians (GPs) regarding antibiotic prescribing and antimicrobial resistance (AMR). A cross-sectional, descriptive AP study was conducted by surveying GPs treating community acquired respiratory tract infections (RTIs) across nine countries, including India, Pakistan, Algeria, Thailand, Vietnam, Egypt, Morocco, the United Arab Emirates, and Saudi Arabia. A 29-item, web-based questionnaire was used to collect data between October-2023 and December-2023. Overall, 9249/14207 invited GPs responded, and 1008 responses were included in the analysis after quality control (3341 terminated due to eligibility, 4764 dropped out without completion, 136 excluded for quality concern). Of the included respondents, 78.8% were male and 98% were aged ≥35 years. 41% of GPs agreed, 33% disagreed, and 27% were neutral to questions regarding whether or not antibiotics are helpful in treating infectious respiratory diseases. In total, 62% of GPs agreed that AMR is a concern in their country and 63% agreed that prescribing antibiotics in primary care results in AMR. Pregnant women and patients with comorbidities were populations for whom selecting an appropriate antibiotic was most challenging; 38% of GPs found prescribing antibiotics to children was difficult. Difficulty in correlating susceptibility data (53%), limited availability of information on antibiotics (52%), and lack of availability of appropriate antibiotics (51%) were important challenges for appropriate antibiotic selection. Overall, 94% of GPs agreed that there is a need for frequent training on antibiotic therapy, with 33% and 49% recommending quarterly and biannual trainings, respectively. This study identified current practices, and possible gaps in appropriate antibiotic prescribing for RTIs. As an outcome, specific training needs could be identified to assist GPs with appropriate antibiotic prescribing in an outpatient setting.

Synthesis and Biological Evaluation of Bicyclic Pyrazolines with Promising Antimicrobial Activities

The efficient photochemical synthesis of bicyclic pyrazolines using flow technology as well as the subsequent antimicrobial evaluation of these scaffolds is reported. Low minimal inhibitory concentration values of 0.5-4 μg mL-1 are found against a series of multidrug resistant bacterial strains including different Staphylococcus and Enterococcus genera species. The lead compound, which is decorated by a halogenated aryl ring system, appears to be bacteriostatic and shows excellent physicochemical and pharmacokinetic properties. Due to low levels of predicted toxicity combined with a high level of drug-likeness, these bicyclic pyrazolines therefore are promising candidates for further studies as antibacterial species.

Pathogen-derived glyoxylate inhibits Tet2 DNA dioxygenase to facilitate bacterial persister formation

Pathogenic bacterial persistence enables survival during antibiotic treatment, leading to treatment failure and recurrent infections, yet its underlying mechanisms remain unclear. Here, we reveal that glyoxylate, a metabolite originally evolved for alternative carbon utilization, functions as a signaling molecule to reprogram the host transcriptome and promote persister formation. Glyoxylate inhibits the DNA dioxygenase TET2, suppressing pro-inflammatory gene expression and attenuating host immune defense. Notably, stimulating TET2 activity with vitamin C or blocking glyoxylate production by Salmonella reduces bacterial antibiotic resistance and improves infection treatment outcomes. Beyond its metabolic role, glyoxylate emerges as a regulator of host-pathogen interactions, while TET2 plays a critical role in preventing bacterial persistence. Our findings suggest that targeting glyoxylate production or enhancing TET2 activity offers promising therapeutic strategies to combat bacterial persistence and enhance the efficacy of antibiotic treatments.

Dodecapeptides derived from human cathelicidin with potent activity against carbapenem-resistant Acinetobacter baumannii

The increasing infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) poses a serious threat to global public health. Antimicrobial peptides (AMPs) are alternatives to conventional antibiotics in combating superbugs. However, discovering AMPs with low synthesis costs and strong antibacterial effects against CRAB is challenging. In this study, we synthesized 28 dodecapeptides for bactericidal assessment by site mutation and all-hydrocarbon stapling on the basis of the antibacterial core of human cathelicidin. The linear derivative d12 (Q5RD9I-KR12) and the i, i + 4 stapled peptide d24, which was generated by substituting Val4 and Lys8 of d12 to staples, stood out among the candidates. These short AMPs efficiently bound to bacterial membrane and penetrated it in a lipid A-dependent manner, resulting in low minimal inhibitory concentrations to inactivate CRAB clinical isolates (2.5-20 μg/mL). The CRAB infection mouse models of irradiation-assisted local pulmonary infection and intra-abdominal sepsis revealed that treatment with d12 and d24 significantly eliminated CRAB in vivo and thereby increased mouse survival. Owing to its improved proteolytic resistance, d24 outperformed d12 in suppressing intra-abdominal CRAB infection. The excellent antibacterial effects, good biocompatibility, and facile synthesis make d12 and d24 promising candidates to curb CRAB infections in different application scenarios.

Synthesis and Antibacterial Properties of 3-Amino-β-Lactams Bearing a Heteroatom-Containing C4 Substituent

The rise of antimicrobial resistance has spurred the search for innovative antibiotics, with monocyclic 3-amino-β-lactams - aztreonam standing out as key example - showing significant potential. In particular, C4-functionalized 3-amino-β-lactams have emerged as a promising subclass that can potentially improve the activity, stability and cellular permeability of the compounds. This review outlines various synthetic methodologies available for the construction of 3-amino-β-lactams bearing a heteroatom-containing substituent at C4, with the heteroatom connected to the ring system either directly or via a methylene bridge. Special attention is devoted to 3-amino-4-hydroxymethyl-β-lactams and 3-amino-4-acetoxy-β-lactams as versatile synthetic intermediates. Moreover, the effect of these C4 substituents on the biological activity of the corresponding 3-amino-β-lactams is discussed in detail. A better understanding of synthetic protocols and antibacterial properties related to this underexplored class of monocyclic 3-amino-β-lactams might contribute to address the current antibiotics problems we are facing more efficiently.