Bacterial Biofilm Formation Research Articles

Disrupting quorum sensing by exploring conformational dynamics and active site flexibility of LasR protein in Pseudomonas aeruginosa

Quorum sensing in Pseudomonas aeruginosa, regulated by the LasR protein, controls bacterial virulence and biofilm formation. Targeting this system offers a promising strategy to combat infections. This study investigates the binding and conformational dynamics of LasR with its native ligand, N-3-oxo-dodecanoyl-L-homoserine lactone (AHL), and a natural product compound, ClaO, using molecular docking, molecular dynamics simulations, and binding free energy calculations. Docking validation confirmed AHL’s accurate re-docking (binding energy: − 8.3 kcal/mol, RMSD: 1.199 Å). ClaO exhibited a stronger binding affinity (− 8.9 kcal/mol), suggesting favorable interactions with LasR. Both ligands formed key hydrophobic and hydrophilic contacts with residues such as TRP60, TYR93, SER129, and ASP73. Molecular dynamics simulations revealed that AHL stabilized the LasR structure, while ClaO induced increased flexibility, indicating different binding mechanisms. Binding free energy analysis showed that ClaO had stronger van der Waals (− 187.6 kJ/mol) and electrostatic interactions (− 139.4 kJ/mol) than AHL (− 182.9 kJ/mol, − 131.8 kJ/mol). However, ClaO’s higher polar desolvation energy (287.2 kJ/mol) reduced its binding efficiency. AHL had a slightly more favorable binding free energy (− 76.3 kJ/mol) compared to ClaO (− 72.6 kJ/mol), suggesting a more stable interaction. These findings highlight the differential effects of AHL and ClaO on LasR stability and flexibility. While ClaO engages in stronger interactions, its desolvation penalty offsets its binding advantage. This study provides molecular insights into quorum sensing inhibition and supports the development of novel LasR-targeting therapeutics. Clinical trial number: Not applicable.Graphical

Characterization of AI-2/LuxS quorum sensing system in antibiotic resistance, pathogenicity of non carbapenemase-producing carbapenem-resistant Escherichia coli

BackgroundAs a quorum sensing system, LuxS/AI-2 is closely associated with bacterial growth, biofilm formation, and virulence. As yet, it is not known how the luxS is associated with a diverse array of physiological activities in non- carbapenemase producing carbapenem resistant Escherichia coli (non-CP-CREC). The purpose of this study is to explore the characterization of AI-2/LuxS quorum sensing system in antibiotic resistance, pathogenicity of non-CP-CREC.MethodsA total of five non-CP-CREC isolates that did not have ompC and ompF deletions were collected from various clinical samples from January 2021 to December 2023. RT-qPCR was used to detect genes expression of luxS, acrA, acrB, tolC, mdtB, mdtC, mdtE, mdtF, ompA, ompX, IL-8, IL-6, and TNF-α. Homologous recombination was used to create the luxS knockout strain. Transcriptome sequencing was utilized to analyze gene expression changes before and after the luxS knockout. Biofilm formation was detected using crystal violet staining. Antimicrobial susceptibility test was used to determine drug resistance. Bacterial growth curves were used to detect the influence of the luxS on bacterial growth. A cell infection assay was used to detect the impact of the luxS on bacterial adhesion and the inflammatory response it induces.ResultsOur results indicated that the expression of the luxS was significantly elevated in non-CP-CREC strains compared to the carbapenem antibiotics sensitive E. coli (CSEC), with CREC229 exhibiting the most pronounced difference. Consequently, CREC229 was chosen for the development of the luxS knockout strain (CREC229△luxS). The deletion of the luxS did not impact the growth of non-CP-CREC. RNA sequencing analysis revealed that 82 genes were differentially expressed, with notable alterations observed in genes associated with biofilm formation regulation and outer membrane proteins in the ΔluxS strain. Our transcriptomic results show that the expression of bssS associated with biofilm formation is significantly reduced in the ΔluxS strain, which in turn reduces its capacity for biofilm formation. In addition, the luxS deletion increased the expression of adhesion-related genes, such as ompA and ompX, enhanced HCT-8 adherence to CREC229, and promoted the secretion of the inflammatory cytokine IL-6. In terms of bacterial resistance, the deletion of luxS increased the sensitivity of non-CP-CRECs to aminoglycoside antibiotics.ConclusionsLuxS/AI-2 quorum sensing systems can alter pathogenicity and resistance in several ways.

Discovering the antibacterial activity of tryptanthrin derivatives for controlling kiwifruit canker and tobacco wilt disease.

Plant bacterial diseases have severely affected the yield and quality of agricultural products, among which kiwifruit canker and bacterial wilt disease, caused by Pseudomonas syringae pv. actinidiae (Psa) and Ralstonia solanacearum (Rs), respectively, seriously restrict the development of the related industry. However, there are few effective green agents available to target these diseases. Herein, we synthesized 41 novel derivatives of the natural product tryptanthrin, among which partial compounds showed noticeable antibacterial activity against Psa and Rs. Compounds T7NO-4 and T7NH-2 can affect bacterial biofilm formation, change the membrane permeability, and cause bacterial necrosis. Compound T7NO-4 exhibits effective control activity against kiwifruit canker disease, with protective and curative efficiency of 75.61% and 66.84%, respectively. Compound T7NH-2 exhibits good protective activity against tobacco wilt disease but poor curative activity. To improve its curative activity, considering the characteristic that bacterial wilt disease is more prone to outbreak under weakly acidic soil conditions, introducing a ZIF-8 framework to make T7NH-2@ZIF-8 nanoparticles that exhibit pH-responsive release, then making T7NH-2@ZIF-8@TA through modifying with tannic acid (TA). T7NH-2@ZIF-8@TA nanoparticles exhibit superior efficacy against tobacco wilt disease. This study demonstrates that 7-piperazine tryptanthrin derivatives exhibit good inhibitory activity against Psa and Rs and may be promising lead agents against plant bacterial diseases, with improved biological activity through being loaded into nanocarriers. © 2025 Society of Chemical Industry.

Comparative Evaluation of Bacterial Adhesion and Biofilm Formation on Contact Lenses

Comparative Evaluation of Bacterial Adhesion and Biofilm Formation on Contact Lenses

Biofilm Growth on Different Materials Used in Contemporary Femoral Head Prosthesis: An In Vitro Study.

Background/Objectives: Periprosthetic joint infection (PJI) primarily results from bacterial biofilms adhering to prosthetic surfaces, making treatment challenging without prosthesis removal. This in vitro study aims to investigate whether the materials used in contemporary femoral head prosthesis influences bacterial biofilm development. Methods: Femoral head prostheses made of three different materials-cobalt-chrome, oxinium, and ceramic-were inoculated with either Staphylococcus aureus or Pseudomonas aeruginosa in separate experiments, with each pathogen tested independently. The samples were cultured under shaking conditions at 37 °C for 96 h to promote biofilm formation. Scanning electron microscopy (SEM) was used to confirm the presence of biofilms, and adherent biofilms were quantified by counting colony-forming units (CFUs) after sonication. Additionally, crystal violet staining was performed to assess biofilm distribution on the femoral head surfaces. Statistical analyses compared CFU counts across the different materials. Results: The mean CFU counts for S. aureus were 7.6 × 105 ± 9.7 × 104 for cobalt-chrome, 6.9 × 105 ± 3.6 × 105 for oxinium, and 1.1 × 106 ± 3.0 × 105 for ceramic femoral head prostheses. For P. aeruginosa, the CFU counts were 2.3 × 106 ± 7.2 × 105, 3.7 × 106 ± 2.5 × 106, and 2.2 × 106 ± 8.9 × 105, respectively. Regardless of the bacterial strain, differences among the three materials were within one log range, and no statistical significance was observed. While biofilms were confirmed using SEM, limited adherence was observed on the bearing surface, with the biofilm predominantly localized in the taper hole. Conclusions: The findings suggest that the material used in contemporary femoral head prostheses has minimal impact on bacterial biofilm formation. Surgeons' choice of femoral head prosthesis material should base their material selection on factors other than PJI prevention.

Physical communication pathways in bacteria: an extra layer to quorum sensing

Physical communication pathways in bacteria: an extra layer to quorum sensing

Rabbit model of a biofilm-contaminated, percutaneous orthopaedic endoprosthesis.

Preclinical models of osseointegrated orthopaedic implants tend to focus on implant stability, surface modifications to enhance integration with host tissue, and reduction in iatrogenic contamination through antibiotic-eluting/bacteria-resistant coatings. While these studies are imperative to early success in osseointegration, continued success of percutaneous devices throughout the lifespan of the patient is also critically important. A perpetual challenge to the implant is formation of bacterial biofilm on the abutment. Once adhered, biofilm-based bacteria are recalcitrant and readily contaminate the subcutaneous soft tissue of the stoma. To this end, the rabbit model reported herein replicates the clinical scenario of a patient with a biofilm-contaminated abutment. This model enables preclinical testing of advanced therapeutics beyond the traditional antibiotic-based approach, potentially increasing the longevity of the device.

Proteomic profiling and pre-clinical efficacy of antimicrobial lithium complex and colistin combination against multi-drug resistant Acinetobacter baumannii.

Proteomic profiling and pre-clinical efficacy of antimicrobial lithium complex and colistin combination against multi-drug resistant Acinetobacter baumannii.

Biological studies reveal the role of trpA gene in biofilm formation, motility, hemolysis and virulence in Vibrio anguillarum.

Biological studies reveal the role of trpA gene in biofilm formation, motility, hemolysis and virulence in Vibrio anguillarum.

Application of double-sleeve endotracheal tube in infection control for icu patients: a randomized controlled trial

BackgroundPoor oral hygiene in patients with tracheal intubation will increase the occurrence of dental plaque and mucosal inflammation, resulting in oral barrier dysfunction. This study aimed to design and evaluate a novel double-lumen endotracheal tube (DETT) and explore its role in infection control, particularly its effects on the oral microenvironment and ventilator-associated pneumonia (VAP).MethodsThis was a prospective, non-blinded, randomized parallel-controlled trial conducted from July 2024 to September 2024. A total of 115 patients who had been intubated for more than 3 days in a tertiary hospital ICU were enrolled and randomly assigned to either the DETT group (n = 58) or the conventional endotracheal tube (ETT) group (n = 57). Both groups received the same oral care protocols. The DETT group was intubated with the double-lumen endotracheal tube, which included a built-in bite block, while the ETT group used a standard endotracheal tube with a bite block. The primary outcome was the incidence of VAP, while secondary outcomes included oral bacterial colony counts, biofilm formation, BOAS oral health scores, and plaque index.ResultsCompared to the ETT group, the DETT group showed a significant reduction in VAP incidence (χ²=4.382, p < 0.05). The DETT group also had significantly lower oral bacterial colony counts (Z=-7.362, P < 0.05) and biofilm formation (χ²=5.472, p < 0.05), as well as better BOAS scores (Z=-2.774, p < 0.05). However, there were no significant differences between the two groups in pathogenic bacterial presence or plaque index (p > 0.05).ConclusionsThe novel double-lumen endotracheal tube effectively reduces the total bacterial load in the oral cavity, inhibits biofilm formation, and lowers the incidence of VAP. It also improves oral function and hygiene, contributing to infection control, and holds significant clinical value.

Enhancing Bacillus thuringiensis Performance: Fertilizer-Driven Improvements in Biofilm Formation, UV Protection, and Pest Control Efficacy

This study investigated the effects of fertilizers on the biofilm formation, ultraviolet (UV) resistance, and insecticidal activity of Bacillus thuringiensis (Bt). Bacillus thuringiensis, a widely used microbial pesticide, has a minimal environmental impact and is highly effective against specific pests but is susceptible to environmental factors in field applications. Bacterial biofilms provide protection for Bt, enhancing its survival and functionality in the environment. However, the mechanisms by which fertilizers regulate the characteristics of microbial pesticides and enhance biofilm formation are not well understood. This study evaluated the effects of six fertilizers on the bacterial biofilm formation, the UV resistance, and the insecticidal activities of Bt wettable powders. The results demonstrated that fertilizers significantly enhanced the performance of three Bt preparations (Lv’an, Kang’xin, and Lu’kang). A compound fertilizer with 8.346 g/L of KCl, 2.751 g/L of ZnSO4·7H2O, and 25.681 μL/mL of humic acid was identified by response surface optimization, achieving the maximum BBF formation with OD595 value of 2.738. Furthermore, KH2PO4, HA, and ZnSO4·7H2O notably improved the survivability of Bt preparations under prolonged UV exposure, with the compound fertilizer providing the greatest protection. What’s more, fertilizers reduced the LC50 values of all Bt preparations, with the compound fertilizer decreasing the LC50 of the Lv’an Bt wettable powder to 0.139 g/L, a 3.12-fold increase in efficacy. This study demonstrated that fertilizers significantly enhance the UV resistance and insecticidal activity of Bt wettable powders by promoting bacterial biofilm formation. Herein, this study provides new strategies and theoretical support for Bt applications in modern sustainable agriculture.

Synthesis, antibacterial evaluation and preliminary mechanism study of novel isoquinoline-3-carboxylic acid derivatives containing an acylhydrazone disulfone moiety.

Limitations in the use and availability of copper-based fungicides and antibiotics has led to a scarcity of bactericidal agents. It is urgent to develop green bactericides with new modes-of-action and effective chemotypes. A bioactive substructure splicing approach was applied to optimize the structure of the natural product isoquinolin-3-carboxylic acid (IQ3CA). The structure-activity relationship analysis showed that the increase of sulfur atomic oxidation state and small groups on the sulfone will be beneficial for antibacterial activities. The difulone compound SF2 showed the most potent activity against Xanthomonas oryzae pv. oryzae (Xoo), Ralstonia solanacearum (Rs) and Acidovorax citrulli (Ac), with median lethal effective concentration values of 2.52, 2.62 and 1.12 μg mL-1, respectively, which were superior to those of IQ3CA and kasugamycin. The protective and curative effects of compound SF2 against Ac were 69.31% and 55.64%, respectively, which were better than those of thiodiazole copper (58.37% and 43.08%). Furthermore, preliminary mechanistic investigations indicated that compound SF2 could increase membrane permeability, reduce exopolysaccharide content, and inhibit both bacterial motility and biofilm formation. A series of novel isoquinoline-3-acylhydrazone derivatives incorporating thioether/disulfone moieties were synthesized, and bioassay results showed compound SF2 demonstrated remarkable antibacterial activity by disrupting bacterial membranes. © 2025 Society of Chemical Industry.

Evaluation of hydrogel loading with curcumin and silver nanoparticles: biocompatibilities and anti-biofilm activities.

Chronic wound healing is associated with prolonged elevated inflammation and high levels of oxidative stress leading to cell death. The majority of wounds are colonized with antibiotic-resistant bacterial biofilms such as Pseudomonas aeruginosa and Staphylococcus aureus. An ideal wound treatment should include agents with antioxidant, anti-inflammatory, and antibiofilm behavior. Therefore, in this study, a combination of curcumin nanoparticle (Cur-NP) and silver nanoparticle (AgNP) (Cur-NP/AgNP) loaded PVA hydrogel was used to inhibit the bacterial attachment and subsequent biofilm formation of P. aeruginosa and S. aureus. Cur was known for its antioxidant and anti-inflammatory effect while being non-toxic to cells. Meanwhile, AgNP demonstrated superior anti-bacterial and antibiofilm activities against both P. aeruginosa and S. aureus. Cur-NP/AgNP loaded PVA hydrogels completely inhibited the bacterial attachment and biofilm formation, possibly due to synergistic effect of Cur-NPs and AgNPs in killing the bacterial cells. It should be highlighted that no surviving bacterial cells were noted for Cur-NP/AgNP loaded hydrogels. On the other hand, AgNPs or Cur-NPs alone loaded hydrogels were unable to achieve complete inhibition of biofilm formation, even though significant reduction in the biofilm mass was noted compared with control samples. Cur-NP and AgNP exerted oxidative-stress induced cell death in HaCaT cells via mitochondrial dysfunction, mitochondrial membrane potential (MMP) reduction, adenosine triphosphate inhibition, and increased cytochrome C release. The toxicity of formulation followed the decreasing trend: Cur-NP/AgNP < AgNPs alone < Cur-NPs alone. Taken together, the combination of Cur-NP/AgNP completely inhibited bacterial biofilm formation through bactericidal effect on the planktonic cells while exerted the least toxic effects towards skin cells.

A Weapon Against Implant-Associated Infections: Antibacterial and Antibiofilm Potential of Biomaterials with Titanium Nitride and Titanium Nitride-Silver Nanoparticle Electrophoretic Deposition Coatings.

Implant-associated infections are a frequent complication of surgeries involving biomaterial implants. Staphylococcus and Enterococcus species are the leading causes of infections linked to bone-anchored and joint implants. To address this challenge, developing antibacterial coatings to prevent bacterial attachment and biofilm formation on biomaterials is critical. This study aimed to evaluate the antibacterial and antibiofilm properties of two biomaterial coatings: titanium nitride (TiN) and titanium nitride with silver nanoparticles (TiN/Ag). Antibacterial activity was tested against common biofilm-forming pathogens, including Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. The results demonstrated that both coatings significantly reduced bacterial cell counts, with the TiN/Ag coating showing superior performance due to the addition of silver nanoparticles. This enhancement was particularly effective in reducing biofilm formation across all the tested strains, with the most pronounced effects observed for E. faecium and E. faecalis. The silver nanoparticles synergistically improved the antibiofilm properties of the TiN coating, efficiently disrupting biofilm integrity and reducing bacterial adhesion. By reducing bacterial attachment and biofilm formation on biomaterial surfaces, TiN/Ag coatings offer a promising strategy to minimize complications associated with biomaterial implants. These findings highlight the potential of TiN and TiN/Ag coatings for medical applications.

Synergistic Potential of Curcumin-Vancomycin Therapy in Combating Methicillin-Resistant Staphylococcus aureus Infections: Exploring a Novel Approach to Address Antibiotic Resistance and Toxicity.

Methicillin-resistant Staphylococcus aureus (MRSA) infections pose serious treatment challenges, particularly in peritoneal dialysis patients due to their increased susceptibility to infections and antibiotic resistance. Vancomycin, a standard antibiotic treatment for MRSA, is currently being compromised due to the evolution of multidrug-resistant microorganisms. Therefore, there is an urgent need for alternative therapeutic strategies to obstruct the increasing antibiotic resistance and bacterial biofilm formation. The present study explores curcumin, a natural bioactive compound possessing antimicrobial and anti-inflammatory properties, as a potential therapeutic for MRSA. The standard optical density method confirmed the antibacterial activity of curcumin against Staphylococcus aureus (MTCC-3160). Furthermore, we investigated the impact of curcumin on bacterial metabolism. Metabolic analysis of S. aureus culture media over a 20-h period revealed that curcumin exerts bacteriostatic effects by inhibiting specific metabolic pathways, potentially linked to energy and sugar metabolism. Furthermore, the synergistic effect of curcumin combined with vancomycin was assessed against 20 clinical MRSA strains using the broth microdilution method. The results demonstrated that curcumin enhanced the antibacterial activity of vancomycin in 17 strains by reducing its minimum inhibitory concentration (MIC) significantly. The MIC of curcumin and vancomycin has been found to decrease significantly when used in combination, with curcumin's MIC decreased to as low as 0.5 µg/mL and vancomycin's MIC to 0.5 µg/mL for all strains. Synergistic effects were seen in 17 out of 20 strains, having fractional inhibitory concentration index values between 0.04 and 0.56. These findings suggest that curcumin-vancomycin combination therapy could offer an effective treatment strategy for MRSA infections which may combat antibiotic resistance and reduce treatment-related toxicity.

Infection-Resistant Polypropylene Hernia Mesh: Vision & Innovations.

The surgical repair of hernias, a prevalent condition affecting millions worldwide, has traditionally relied on polypropylene (PP) mesh due to its favorable mechanical properties and biocompatibility. However, postoperative infections remain a significant complication, underscoring the need for the development of infection-resistant hernia meshes. This study provides a comprehensive analysis of current advancements and innovative strategies aimed at enhancing the infection resistance of PP mesh. It presents an overview of various research efforts focused on the integration of antimicrobial agents, surface modifications, and the development of bioactive coatings to prevent bacterial colonization and biofilm formation. Additionally, the synergistic effects of novel material designs and the role of nanotechnology in optimizing the anti-infective properties of PP mesh are explored. Recent clinical outcomes and in vitro studies are critically examined, highlighting challenges and potential future directions in the development of next-generation hernia meshes. Emphasis is placed on the importance of interdisciplinary approaches in advancing surgical materials with the ultimate goal of improving patient outcomes in hernia repair.

Synthesis and Evaluation of Colchicine C-Cyclic AmineDerivatives as Potent Anti-Biofilms Agents AgainstMethicillin-Resistant Staphylococcus aureus.

The elimination of bacterial biofilm formation is an effective strategy against bacterial infections. The objective was to design 27 colchicine C-ring modified amine derivatives and evaluate their inhibitory activities against the biofilms of MRSA USA300. Design 27 colchicine C-ring modified amine derivatives. Evaluate their inhibitory activities against MRSA USA300 biofilms. Conduct antibacterial or synergistic antibacterial experiments. Research the phenotypic mechanisms related to biofilm-related genes icaA and agrA. The experiments showed that most compounds in this series exhibited varying degrees of biofilm inhibitory activity (with inhibition rates ranging from 7.72% to 40.79%). Further verification through antibacterial or synergistic antibacterial experiments revealed that the compounds with biofilm-inhibiting effects (compounds 7b-11b) generally had certain antibacterial activities (MICs = 16-32 μg/mL) or synergistic antibacterial effects (FICIs < 0.5). Furthermore, through in-depth research on their phenotypic mechanisms (i.e., research on biofilm-related mechanisms), it was found that the compounds with antibacterial or synergistic antibacterial properties could inhibit the formation of biofilms by affecting the regulation of the biofilm-related genes icaA and agrA. The designed colchicine C-ring modified amine derivatives showed potential in inhibiting MRSA biofilms, and their antibacterial or synergistic antibacterial properties are related to the regulation of biofilm-related genes icaA and agrA, demonstrating inhibitory activity against MRSA.

Degradation of polyvinyl chloride (PVC) microplastics employing the actinobacterial strain Streptomyces gobitricini.

The disposal of plastic materials has resulted in the huge increase of microplastics in the environment. One of the most hazardous plastic waste is polyvinyl chloride (PVC) due to its durability. A tool to remediate PVC microplastic polluted environment might be offered by microorganisms such as Actinobacteria, which has been proven to degrade PVC. Streptomyces gobitricini was isolated from soil polluted by heavy metals and plastic debris and used in a PVC microplastics degradation experiment. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM) were used to study the characteristics of microplastic particles. For the incubation, the optimal pH 7.5 was determined in a preliminary experiment where also pH 5.5 and pH 9.5 were included. Three PVC concentrations (200, 400, and 800mg/L) were incubated in Luria-Bertani broth with S. gobitricini for 90days. After the incubation, PVC-MP particles were recovered by filtering. The percentual weight loss of microplastics was highest (66%) in 200mg/L treatment. Relatively high reductions were observed for the higher microplastic concentrations as well (400mg/L; 65% and 800mg/L; 60%). The bacterial growth decreased in order 200mg/L (3.1 ± 0.1CFU × 105/mL), 400mg/L (3.0 ± 0.0CFU × 105/mL) and 800mg/L treatment (2.7 ± 0.0CFU × 105/mL). High hydrophobicity was observed in all treatments at the end of the incubation indicating the formation of bacterial biofilm on the surfaces of plastic particles. The highest hydrophobicity (84%) associated with the bacterial strain was observed in 200mg/L microplastics treatment. The results show that the bacterium S. gobitricini suits for further studies to reduce PVC microplastic waste in the environment.

Combating enteropathogenic and multidrug resistant Escherichia coli using the lytic bacteriophage vB_EcoM_ECO78 which disrupts bacterial biofilm formation and exhibits a remarkable environmental stability.

The current study aimed to establish a phenotypic and genotypic characterization record of a novel lytic bacteriophage (phage) against multidrug-resistant (MDR) Escherichia coli (E. coli) infections. Phenotypic characterization of the isolated phage included the assessment of phage morphology, host range, stability, and antibiofilm activity. The isolated phage vB_EcoM_ECO78 demonstrated high lytic activity against MDR E. coli and E. coli serotypes O78:K80:H12 and O26:H11. Additionally, it showed a marked antibiofilm activity and high physical stability at a wide range of temperatures and pH. Genotypic investigations identified a double-stranded DNA genome of 165 912 base pairs (bp) spanning 258 open reading frames (ORFs), out of which 149 ORFs were identified and annotated. In vivo analysis further confirmed the therapeutic potential of vB_EcoM_ECO78 which effectively increased the survival of mice infected with MDR E. coli. The isolated phage vB_EcoM_ECO78 exhibits considerable stability and antibiofilm activity against MDR E. coli isolates, supported by notable environmental fitness and in vivo antibacterial capability.

Antibiofilm Activities of Halogenated Pyrimidines Against Enterohemorrhagic Escherichia coli O157:H7.

Enterohemorrhagic Escherichia coli (EHEC) is a significant public health concern due to its ability to form biofilms, enhancing its resistance to antimicrobials and contributing to its persistence in food processing environments. Traditional antibiotics often fail to target these biofilms effectively, leading to increased bacterial resistance. This study aims to explore the efficacy of novel antibiofilm agents, specifically halogenated pyrimidine derivatives, against EHEC. We screened pyrimidine and 31 halogenated pyrimidine derivatives for their antimicrobial and antibiofilm activities against EHEC using biofilm quantification assays, SEM analysis, motility, and curli production assessments. Our findings reveal that certain halogenated pyrimidine derivatives, notably 2-amino-5-bromopyrimidine (2A5BP), 2-amino-4-chloropyrrolo[2,3-d]pyrimidine (2A4CPP), and 2,4-dichloro-5-iodo-7H-pyrrolo[2,3-d]pyrimidine (2,4DC5IPP) at 50 µg/mL, exhibited significant inhibitory effects on EHEC biofilm formation without affecting bacterial growth, suggesting a targeted antibiofilm action. These compounds effectively reduced curli production and EHEC motility, essential factors for biofilm integrity and development. qRT-PCR analysis revealed that two active compounds downregulated the expression of key curli genes (csgA and csgB), leading to reduced bacterial adhesion and biofilm formation. Additionally, in silico ADME-Tox profiles indicated that these compounds exhibit favorable drug-like properties and lower toxicity compared with traditional pyrimidine. This study highlights the potential of halogenated pyrimidine derivatives as effective antibiofilm agents against EHEC, offering a promising strategy for enhancing food safety and controlling EHEC infections. The distinct mechanisms of action of these compounds, particularly in inhibiting biofilm formation and virulence factors without promoting bacterial resistance, underscore their therapeutic potential.