Search Results (709)

Background/Objectives: Skin and soft tissue infections (SSTIs) represent a significant clinical challenge, largely due to the high prevalence of antibiotic-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). Treatment is further complicated by biofilm formation, which reduces antibiotic efficacy. The limitations of conventional therapies highlight the need for alternative approaches. Phage therapy has emerged as a promising biological strategy; however, its effectiveness may be constrained by factors such as phage instability and biofilm regrowth. This study aimed to enhance phage-based treatment by combining a newly isolated phage, vB_Sau-E, with lactoferrin (Lf), a multifunctional protein of the innate immune system. Methods: Phage vB_Sau-E was characterized in terms of its infection dynamics and lytic activity. Biocompatibility was further examined using human skin cell lines. The potential effect of Lf was assessed by evaluating its impact on phage infectivity and stability under a range of environmental conditions and by checkerboard assay. Results: Phage vB_Sau-E belongs to the Silviavirus genus in the Herelleviridae family. It was shown to infect 12 out of 22 tested clinical MRSA isolates, with 10 strains identified as good hosts. The phage has a ~30 min life cycle, and ~50 progeny virions are released after bacterial cell lysis. We have also observed that Lf increased plating efficiency and enhanced phage stability at a pH of 5.5 and at −20° C. It also proved to have an additive antibacterial effect, though this was observed to be strain-dependent. Conclusions: Lactoferrin functions as a stabilizing adjuvant for phage vB_Sau-E. Its additive effect supports the development of more effective, biofilm-targeting therapies for staphylococcal SSTIs. Full article

Antibiotic resistance is a growing global health threat. However, its evolution cannot be fully understood without considering antibiotic tolerance and persistence. Persister cells are phenotypic variants that survive lethal antibiotic exposure without heritable resistance, primarily through growth arrest, metabolic slowdown, and stress-adaptive states. Although persistence has been viewed as a transient survival phenomenon, increasing evidence suggests that it may also have a genetic basis by preserving populations during antibiotic-induced bottlenecks and enabling regrowth, mutation, and selection under certain conditions. This review examines the molecular mechanisms underlying persister formation, including toxin–antitoxin systems, stringent-response signaling, ATP depletion, translational arrest, and stress-response networks. We discuss how persistence contributes to antibiotic tolerance in biofilms, host environments, and recurrent infections, and how repeated antibiotic exposure may promote stepwise evolution from phenotypic survival to stable resistance in specific contexts. Evidence from experimental evolution, clinical observations, and system-level analyses supports a potential but context-dependent link between persistence and resistance. We also highlight therapeutic strategies targeting persister cells, including antipersister compounds, metabolic activation, combination therapies, bacteriophages, and alternative approaches. Finally, we outline future research directions, emphasizing single-cell technologies, systems biology, longitudinal clinical studies, and evolution-informed treatment design. A comprehensive understanding of persistence and its evolutionary implications is essential for improving treatment efficacy and limiting the emergence of long-term antibiotic resistance. Full article

Bacterial sexually transmitted and sexually associated infections remain a major global health concern, increasingly complicated by antimicrobial resistance and the limited effectiveness of existing therapies. In this context, bacteriophage-based and phage-derived approaches have re-emerged as potential alternative antibacterial strategies. This narrative review examines their applicability across key bacterial pathogens associated with sexually transmitted infections, including Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Treponema pallidum and biofilm-associated bacterial vaginosis, with a particular focus on pathogen-specific biological barriers. Available evidence indicates that the success of phage-based interventions is strongly dependent on factors such as intracellular localisation, structural characteristics of the bacterial envelope and the presence of polymicrobial biofilms. While phage-derived platforms, including endolysins, depolymerases and engineered phages, demonstrate antibacterial activity in experimental settings, their effectiveness is uneven across different pathogens. Biofilm-associated infections appear more accessible to these approaches, whereas intracellular and structurally atypical bacteria are currently considered more challenging targets based on available mechanistic and experimental evidence. These observations highlight the need for pathogen-specific engineering strategies and delivery systems. Overall, phage-based therapeutics in this field should be considered within a framework that integrates biological constraints with targeted antimicrobial design. Full article

Cystic fibrosis (CF) lung disease is characterized by chronic infection and progressive airway damage, driven by interactions between epithelial dysfunction, immune dysregulation, and microbial adaptation. Defective cystic fibrosis transmembrane conductance regulator (CFTR) function disrupts airway hydration and mucociliary clearance, creating a microenvironment that facilitates infection, particularly with Pseudomonas aeruginosa (P. aeruginosa). Within this environment, P. aeruginosa undergoes adaptive changes, including biofilm formation and metabolic reprogramming, which support long-term survival in the airway. Concurrently, host immune responses become dysregulated, with ineffective bacterial clearance and sustained neutrophil-dominated inflammation contributing to tissue injury. These processes establish a self-reinforcing cycle that drives disease progression. Importantly, early infection represents a critical therapeutic window during which bacterial populations remain more amenable to eradication before irreversible airway remodeling occurs. Delayed intervention promotes transition to a more treatment-refractory state and accelerates disease progression. Despite the clinical benefits of CFTR modulators, airway damage and established infections often remain. The relative contributions and interactions of epithelial dysfunction, immune dysregulation, and bacterial adaptation in sustaining chronic infection remain incompletely defined, representing a key knowledge gap. In this context, this review aims to integrate current evidence on host–pathogen co-adaptation in CF lung disease, with a particular focus on P. aeruginosa, and highlight emerging therapeutic strategies. Full article

To prevent the spread of antibiotic resistance, bacteriophages have gradually become the most promising alternative to antibiotics for treating bacterial infectious diseases. In this study, using E. coli DC1 as the host strain, we isolated a bacteriophage named Escherichia coli phage XJA18 from farm sewage. We conducted morphological identification, host range determination, biological characteristic analysis, genomic feature analysis, and evaluation of in vitro and in vivo antibacterial effects. Electron microscopy revealed that phage XJA18 belongs to the class Caudoviricetes, with an icosahedral head and a non-contractile long tail. Whole-genome sequencing revealed that the phage has dsDNA with a length of 50,572 bp, with a GC content of 45.33%. The genome does not contain any antibiotic resistance genes or virulence genes, indicating good safety. XJA18 showed lytic activity against 24% of clinically isolated E. coli strains. The optimal multiplicity of infection (MOI) was 0.001, with a latent period of 10 min, a burst period of 30 min, and a burst size of 2.22 × 10² PFU/cell. It remained stable at 4–50 °C and pH 4–12. In vitro antibacterial results revealed that XJA18 had the most pronounced initial bacterial growth suppression at MOI = 0.001 during the first 4 h. In vivo experiments demonstrated that both prophylactic and therapeutic administration of XJA18 could protect against E. coli infection, significantly reducing inflammatory cytokine levels and bacterial loads in the livers and spleens of mice (p < 0.001), significantly increasing body weight (p < 0.05), and reducing histopathological damage to the colon, liver, and lungs. In summary, phage XJA18 can effectively inhibit E. coli and is safe and stable. These characteristics indicate that phage XJA18 has great potential as a novel biological agent to replace antibiotics for treating bacterial infectious diarrhea in calves. Full article

Background: The emergence of multidrug-resistant (MDR) Gram-negative pathogens, namely Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Helicobacter pylori, necessitates urgent therapeutic alternatives. This scoping review aimed to summarize the current evidence on the efficacy of lytic bacteriophages against these critical MDR pathogens, and to identify existing research gaps and implementation challenges. Methods: The literature search was conducted by searching PubMed, Web of Science, and Scopus AI for studies published from 2015 to 2025. The inclusion criteria focused on experimental and human studies evaluating phage therapy against MDR, extensively drug-resistant (XDR), or pan-drug-resistant (PDR) strains in the four target species. A total of 172 articles were included. Results: A number of studies showed an increasing trend (2015–2025), focusing mainly on K. pneumoniae (n = 65), P. aeruginosa (n = 55), and A. baumannii (n = 48). No eligible studies for MDR H. pylori were found. All 172 studies confirmed lytic activity, with phage cocktails showing superior antibacterial activity than single phages in four studies. Phages also demonstrated antibiofilm activity (n = 44). Most animal studies reported successful bacterial reduction in animals treated with phages, and 87.5% of 23 human case studies reported patient improvement or infection clearance. However, heterogeneity in the types of animal models used and in dosage and administration routes in human studies was notable. Conclusions: Lytic bacteriophages exhibit strong potential as a new therapeutic option. Key challenges include the lack of data for MDR H. pylori, heterogeneity in animal models, and a paucity of large-scale human clinical trials. Future research must prioritize standardization, mechanistic studies, and conducting robust human trials to enable clinical translation and regulatory acceptance. Full article

Rising antimicrobial resistance has revived global interest in phage therapy, yet its transition to standard clinical practice remains slow. This challenge is not solely due to a lack of efficacy. Instead, we face a fundamental conceptual barrier caused by an “evaluation mismatch.” Traditional regulations treat phages as static chemical molecules—like taking a “snapshot.” However, biologically, phages are dynamic, evolving populations—more like a living “movie.” In this review, we use Schrödinger’s cat metaphor to explain this reality: phage variability is not a defect, but an essential feature. To bridge this gap, we propose a Controlled Evolutionary Platform. By distinguishing between a fixed “Safety Core” and a fluctuating “Adaptive Periphery,” we can manage viral evolution rather than trying to stop it. Ultimately, to integrate phages into modern medicine, we must redefine “consistency”: shifting our focus from preserving a fixed genetic sequence to ensuring the reliable performance of population dynamics. Full article

Antimicrobial resistance (AMR) has become a major concern in the treatment of bacterial infections, and bacteriophage therapy has emerged as a promising alternative to antibiotics. Bacteriophages are highly specific to their bacterial hosts; hence, isolating phages indigenous to a specific region offers a significant advantage against various pathogen strains. We have isolated a cocktail of bacteriophages against pathogenic E. coli from sewage water at a primary healthcare centre. Characterisation of the isolated phages demonstrated their stability across a broad pH and temperature range, strong lytic activity, and effective biofilm degradation, with no cross-reactivity with Staphylococcus aureus (S. aureus). Genomic analysis and phylogenetic studies indicated that the largest phage (by genome size) in the cocktail belongs to the genus Vequintavirus (myoviruses, rV5-like phages), and its genome sequence has been deposited in NCBI (Accession ID: PX741096). The phage genome was linear, with headful (PAC) packaging, encoded lysis proteins, and lacked antibiotic-resistant or major lysogeny-associated genes, collectively suggesting a lytic lifestyle. These findings emphasize the therapeutic potential of rV5-like phages and underscore the critical need to establish phage banks in India to improve disease management. Full article

Percutaneous cable infection of left ventricular assist device (LVAD) patients is a significant source of morbidity, often caused by biofilm-producing or multidrug-resistant bacteria. We hypothesized that bacteriophage viruses can be identified from biological samples of patients with active driveline infection. Six patients with local percutaneous lead infections were enrolled. Microbiological samples were collected from the infected wound and other skin regions. The isolated viral strains and phages from wastewater samples were then tested against the pathogen bacterial cultures in vitro. Biofilm disruption assay and genetic analysis of the strains were also performed. Bacteriophages with lytic activity could be identified from samples of two patients. One patient contained four strains showing strong efficacy against his own Staphylococcus epidermidis. Furthermore, this bacterium was susceptible to phages identified from another patient and strains from wastewater samples. Genomic analysis suggested lysogenic lifestyle of the phages. However, none of them have shown any microbiological signs of lysogeny. In conclusion, we have been able to prove in vitro lytic activity of bacteriophages originating from the same LVAD patient. We also found effective phages in biological samples of other patients and wastewater samples, suggesting that patients implanted in the same center may share bacteriophage flora. Full article

Background/Objectives: The escalating crisis of antibiotic resistance and the inherent limitations of conventional antibiotics necessitate the development of innovative therapeutic strategies. Targeted drug delivery (TDD) offers a powerful approach to enhance efficacy, minimize systemic toxicity, and circumvent bacterial resistance. This systematic review aims to evaluate the potential of unique bacterial transport systems (BTSs), surface specific receptors and intracellular enzymes as platforms for TDD via the “Trojan Horse” strategy (THS). Methods: A comprehensive literature review was conducted, focusing on studies that investigated the specificity and mechanisms of BTSs responsible for the uptake of metabolites that are essential for and unique to bacteria. This includes an analysis of transport systems for siderophores, bacteria-specific sugars, cell wall components, D-amino acids, and vitamins. We assessed preclinical and clinical examples of drug conjugates utilizing these pathways, as well as emerging platforms such as bacteriophage-derived proteins, antibody–antibiotic conjugates, and bacterial extracellular vesicles (EVs). Results: BTSs demonstrate high specificity for their cognate substrates, providing effective molecular gateways for TDD of drugs photosensitizers and diagnostic probes in form of conjugates. The siderophore–cephalosporin conjugate cefiderocol represents a clinically validated example, having received FDA approval. Preclinical studies further reveal that conjugates utilizing sugars (e.g., maltose, trehalose) and vitamins (e.g., B12) can significantly enhance antibiotic uptake and activity against both Gram-positive and Gram-negative pathogens, including drug-resistant strains. Emerging platforms like bacteriophage endolysins and engineered EVs show promise for overcoming biological barriers such as bacterial outer membranes and intracellular host niches. Conclusions: The THS leveraging BTSs represents a clinically viable and promising avenue for next-generation antibacterial therapies. Advantages of BTS include overcoming bacterial resistance, such as reduced membrane permeability and efflux pumps, enabling the “revival” of antibiotics that are poorly permeable or toxic, increasing their local concentration at the target site and reducing side effects on host cells. While significant progress has been made, a striking disconnect persists between the hundreds of conjugates demonstrating potent in vitro activity and the limited agent that has achieved clinical use. This in vitro–in vivo gap reflects, in large part, the early stage of this field rather than a fundamental failure. Further research is critically needed not only to identify novel BTSs and optimize drug-linker chemistry, but also to systematically address the translational barriers—including poor pharmacokinetics, immunogenicity, and unexpected toxicity—that have prevented most promising candidates from advancing beyond preclinical evaluation. Full article

Bacterial biofilms are structured microbial communities enclosed within a self-produced extracellular polymeric substance matrix composed of polysaccharides, proteins, extracellular DNA, and lipids. This matrix promotes adhesion, structural stability, and the development of heterogeneous microenvironments that restrict antimicrobial penetration and shield bacteria from host immune responses. As a result, biofilms are major contributors to chronic, recurrent, device-related, and difficult-to-treat infections, posing a major challenge for clinical management and antimicrobial stewardship. This review summarizes current understandings of biofilm biology, its clinical relevance, including the stages of biofilm development, the composition and protective roles of the matrix, and the physiological heterogeneity that arises during maturation. It also examines key mechanisms underlying biofilm tolerance and resistance, such as limited antibiotic diffusion, and sequestration, enzymatic inactivation, efflux pump upregulation, persister cell formation, and horizontal gene transfer. In addition, it highlights important clinical settings in which biofilms are implicated, including cystic fibrosis, chronic wounds, osteomyelitis, implant- or device-associated infections, and breast implant illness, in which persistent implant-associated biofilms and the resulting chronic inflammatory milieu have been hypothesized to contribute to local and systemic manifestations in a subset of patients. The review further discusses conventional and emerging approaches for biofilm detection alongwith real-time monitoring. Biofilm-associated infections remain difficult to eradicate because persistence is driven by multiple interconnected protective mechanisms. Effective management therefore requires integrated strategies that combine accurate detection with multifaceted therapies, including antibiotics alongside matrix-disrupting enzymes, quorum-sensing inhibitors, bacteriophages, metabolic reactivators, and nanotechnology-based delivery systems. Advances in multi-omics and system-level modeling will be essential for developing next-generation strategies to prevent, monitor, and treat biofilm-associated disease. Full article

Foodborne pathogens of Enterobacteriaceae are becoming an increasing global concern, with multidrug-resistant strains posing significant risks to food safety and public health, especially in high-risk products like dairy. This research focused on isolating, biologically characterizing, and genomically profiling new bacteriophages that target key Enterobacteriaceae members as potential biocontrol agents. Eight phages were isolated from wastewater using four bacterial hosts and analyzed through transmission electron microscopy, one-step growth analysis, adsorption kinetics, host range evaluation, whole-genome sequencing, comparative genomics, phylogenetic analysis, proteomic profiling, and virion assembly pathway characterization. All eight isolates exhibited icosahedral heads with contractile tails typical of Myoviridae morphology, demonstrated broad-spectrum lytic activity against 21 bacterial strains (infectivity: 47.6–95.2%), showed high adsorption efficiencies (84.75–99.98%), and had burst sizes ranging from 11 to 166 particles per cell. Genome sizes varied from 103 to 170 kb with coding densities between 92–96%. Importantly, none contained antimicrobial resistance genes, virulence factors, or lysogeny-associated elements, confirming their strictly lytic lifestyles and favorable biosafety profiles. Phylogenetic and comparative analyses indicated mosaic genomic structures influenced by horizontal gene transfer rather than host phylogeny. These findings provide a robust biological and genomic basis for evaluating these phages as potentially safe and effective alternatives to antibiotics in controlling foodborne Enterobacteriaceae, pending further in situ validation. Full article

Gut dysbiosis, defined as a disruption in the structure or function of the intestinal microbiota, is increasingly recognized as a key contributor to inflammatory, metabolic, and neuropsychiatric diseases. Conventional interventions such as broad-spectrum antibiotics, generic probiotics, and fecal microbiota transplantation (FMT) often show limited and inconsistent efficacy because they lack specificity, durability, and robust safety controls. In contrast, recent advances in DNA-based technologies are reshaping the therapeutic landscape by enabling targeted, programmable, and mechanistically informed modulation of the gut ecosystem. This review presents an integrated overview of three major domains driving this shift: CRISPR-based systems that selectively delete, silence, or reprogram microbial genes; synthetic biology-driven live therapeutics engineered to sense disease-associated cues and execute controlled responses; and metagenomics-informed strategies that tailor interventions to patient-specific microbial gene profiles and functional deficits. Additionally, we examine the continued evolution of FMT toward DNA-optimized workflows and defined microbial consortia that offer safer, more standardized alternatives to crude donor material. Across these domains, we discuss delivery platforms (including bacteriophages, conjugative plasmids, extracellular vesicles, and synthetic nanoparticles), and compare their efficiency, specificity, and scalability. We further highlight how DNA-guided interventions interface with host immunity—shaping Treg/Th17 balance, mucosal barrier function, and inflammatory signaling—while also analyzing ecological and evolutionary risks, biocontainment strategies, and regulatory classification gaps that will govern clinical translation. Together, these developments signal a transition from empirical microbiome manipulation to rational ecosystem engineering. DNA-guided therapies hold strong promise for precise and personalized management of gut-related diseases, but their success will depend on rigorous ecological risk assessment, long-term monitoring, and adaptive regulatory frameworks alongside continued technological innovation. Full article

Carbapenem-resistant Gram-negative infections have become one of the most formidable challenges in intensive care units (ICUs). Critically ill patients—often exposed to invasive procedures, prolonged hospitalization, and broad-spectrum antibiotics—are highly susceptible to infections by carbapenem-resistant Enterobacterales (CRE), Pseudomonas aeruginosa (CRPA), and Acinetobacter baumannii (CRAB). These pathogens are associated with mortality exceeding 40%, prolonged ICU stays, and increased healthcare costs. Therapeutic advances have reshaped management in recent years. New β-lactam/β-lactamase inhibitor combinations—ceftazidime–avibactam, meropenem–vaborbactam, imipenem–relebactam, and sulbactam–durlobactam—along with cefiderocol, have provided safer and more effective alternatives to previously used regimens. Yet, none are universally effective, particularly against carbapenemase-producing organisms, especially metallo-β-lactamase (MBL) producers, and resistance may still emerge during treatment. Rapid molecular and phenotypic diagnostics, when integrated into antimicrobial stewardship, have improved early therapy alignment and reduced unnecessary broad-spectrum use. Beyond antibiotics, colonization surveillance and infection control remain pivotal, as colonization often precedes invasive infection. Biofilm formation on devices such as endotracheal tubes and catheters further promotes persistence and relapse. Strategies targeting biofilm disruption, improved dosing guided by pharmacokinetic/pharmacodynamic optimization, and therapeutic drug monitoring are crucial in ICU practice. The future of managing these infections will depend on integrating precision tools—rapid diagnostics, mechanism-based therapy, and stewardship-guided decisions—with emerging treatments and adjunctive options such as immunomodulators, bacteriophages, and AI-driven decision support. Continued research in ICU-specific populations, especially regarding pharmacokinetics in patients on ECMO or CRRT, is urgently needed. In summary, while the therapeutic landscape for carbapenem-resistant Gram-negative infections has evolved substantially, sustained success will rely on a multifaceted strategy combining innovation, precision, and prevention to improve outcomes for the most vulnerable patients. Full article

Chryseobacterium indologenes MA9 is a causative agent of root rot disease in Panax notoginseng (P. notoginseng), with its high incidence being a major manifestation of continuous cropping barriers, severely hindering the sustainable development of the P. notoginseng industry. In this study, a novel lytic bacteriophage, MA9V-3, was isolated from wastewater, targeting C. indologenes MA9. The phage produced clear plaques, ranging from 1 to 3 mm in diameter, with a surrounding halo. Phage MA9V-3 achieved an adsorption rate of up to 80% after 30 min of contact with C. indologenes MA9, a latent period of approximately 40 min, and an average burst-size if 160 PFU/cell. Transmission electron microscopy revealed that phage MA9V-3 possesses an icosahedral head and a contractile tail, exhibiting a typical myovirus-like morphology. According to the latest ICTV taxonomy, MA9V-3 belongs to the class Caudoviricetes, and the phage’s biocontrol efficacy and inhibitory capacity were evaluated at different multiplicity of infection (MOI s). The results showed that the highest titer recorded at 1.6 × 10¹⁰ PFU/mL. Whole-genome sequencing revealed that MA9V-3 is a double-stranded circular DNA virus, with a genome length of 103,203 bp, GC content of 34.29%, and 150 open reading frames (ORFs), one of which is related to tRNA. Only 13 of these ORFs encode known functional sequences, likely due to the limited available gene data for such phages in the database, with additional details on hypothetical proteins yet to be uncovered. Comparative database analysis confirmed that the phage genome contains no antibiotic resistance or toxin-related genes. Phage therapy experiments were performed using MA9V-3 and two other phages screened in our laboratory. The experimental results showed that phage MA9V-3 may be a potential candidate for effectively controlling the infection of Panax notoginseng by C. indologenes MA9, and offering valuable insights into the potential application of phage therapy for managing bacterial plant diseases. Full article